Novel Pyrazole Derivatives and their Dyes; Synthesis and ...
Transcript of Novel Pyrazole Derivatives and their Dyes; Synthesis and ...
Novel Pyrazole Derivatives and their Dyes; Synthesis
and Applications
A dissertation submitted to the Institute of Chemistry,
University of the Punjab, Lahore, in fulfillment
of the requirements for the degree of
Doctor of Philosophy
in
Chemistry
by
Ghulam Hussain
Institute of Chemistry
University of the Punjab
Lahore
2017
i
ACKNOWLEDGEMENT
All praises for the most merciful Almighty ALLAH, Who enabled me with the blessings of His
Prophet Hazrat Muhammad (PBUH),Whose teachings inspired me to wider my thoughts and
deliberate the things deeply and to complete this dissertation.
I am obliged to pay my heartiest thanks and gratitude to my learned Supervisors Prof. Dr.
Muhammad Makshoof Athar, Director Institute of Chemistry, University of the Punjab Lahore
and Dr Misbahul Ain Khan, Professor Emeritus Islamia University Bahawalpur for their
enthusiastic guidance and inspiration for the submition of this dissertation.
I feel it a great pleasure to express my thanks to all of the respected teachers of the Institute of
Chemistry, University of the Punjab, Lahore for their cooperation and continuous moral support
during my research.
From the core of my heart I am thankful to Prof. Dr. Aamir Saeed, Department of Chemistry,
Quid-e-Azam University Islamabad and Dr. Ghulam Shabir Assistant Professor of Chemistry,
Govt. Gorden College, Rawalpindi for their help in my publications and the completion of my
thesis.
I am very great full to Mr. Abrar Ahmad Chief Executive Officer SRC Pvt. Ltd. and Mr.
Muhammad Faheem Chief of Operations SRC Pvt. Ltd., Lahore Pakistan for providing me
financial and technical assistance for the evaluation of my novel Dyes. I am also very thankful to
all the technical Staff of SRC Pvt. Ltd. especially Mr. Mohammad Naveed Ashraf and Dr.
Rashid Saleem, Managers R&D for their thorough help in the completion of my task.
It is also my fortune to pay my thanks to all my friends especially Prof. Dr. Tahir Nawaz, Prof.
Dr. Zafar Iqbal, University of Sargodha and Dr. Hazoor Ahmad Shad Associate Professor of
Chemistry, Govt. College Jhang for their technical assistance to achieve my this goal.
At the last but not the least, I am thankful to all my family members for their cooperation and
prayers to complete my dissertation.
GHULAM HUSSAIN
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List of Figures
S.No. Figure Captions Page No.
Figure 1.1 Tautomeric forms of hydroxypyrazoles (1-3) 1
Figure 1.2 Phenazone (2,3-dimethyl-1-phenyl-5-pyrazolone) as Antipyretic and
Analgesic 1
Figure 1.3 Pyrimidon, 4-Dimethylamino-1,5-dimethyl-2-phenylpyrazol-3-one 2
Figure 1.4 Pyrazole derivative, Butazolidin 4-butyl-1,2-diphenyl-pyrazolidine-3,5-
dione as rheumatoid arthritis 2
Figure 1.5 Sodium1-phenyl-2,3-dimethyl-5-pyrazolone-4-methylamino-
methylsulfonate 2
Figure 1.6 Pyrazolone derivatives as anti-inflammetry drugs 3
Figure 1.7 pyrazole C-glycoside pyrazofurin; 4-hydroxy-3-β-D-ribofuranosyl 1H-
pyrazole-5-carboxamide 3
Figure 1.8 Thiadiazole substituted pyrazole -5-one as anti-cancer drug 4
Figure 1.9 Pyrazole derivative, 4,4-dichloro-1-(2,4dichlorophenyl)-3methyl-5-one
as anti-cancer drug 4
Figure 1.10 Tartarzine, pyrazolone based dye 5
Figure 1.11 sheet diagram for classification of dyes based on their Application 6
Figure 1.12 Flow sheet diagram for classification of dyes based on their Application 6
Figure 1.13 Acidic Metal complex 7
Figure 1.14 Basic Yellow 2, a diarylmethane dye 7
Figure 1.15 C.I. Direct Black 78 8
Figure 1.16 Anthraquinone dye; C.I. Disperse Blue 19 8
Figure 1.17 Fluorescent Brighteners. imidazoline derivative 9
Figure 1.18 C.I. Food Red 3 9
Figure 1.19 C.I. Mordant Red 7 9
Figure 1.20 Oxidation base, Indamine Blue Hair Dye 10
Figure 1.21 H-acid base Reactive Dye 10
Figure 1.22 Anthraquinone type Solvent dye 10
Figure 1.23 Anthraquinone type Vat dye 11
Figure 1.24 Pyrazole based Acid Dye 11
Figure 1.25 Pyrazole based Disperse Dye 12
Figure 1.26 Pyrazole based Mordant Dye 12
Figure 1.27 Pyrazolone based Reactive Dye 13
Figure 1.28 Pyrazolone based Metal Complex Dye 13
Figure 1.29 Pyrazole based Vat Dyes 13
Figure 1.30 Pyrazolone based cationic dyes used for polyamide fibers 14
Figure 1.31 Oxanol and oxanol derivatized dyes used in Photography 15
Figure 1.32 Pyrazolone and Triazole based Dyes 16
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Figure 1.33 Pyrazole based Hair Dyes 16
Figure 1.34 Neutral Fluorescence Whitening Agents 17
Figure 1.35 Anionic Fluorescence Whitening Agents 17
Figure 1.36 Cationic Fluorescence Whitening Agents 17
Figure 2.1 Different Tautomeric forms of Pyrazolones 23
Figure 2.2 Four Tautomeric forms of substituted Pyrazolones 24
Figure 2.3 Antidepressant pyrazoles 35
Figure 2.4 Antidepressant and antituberclosis pyrazoles 35
Figure 2.5 Antimicrobial pyrazole derivatives 35
Figure 2.6 Antiamoebic pyrazole derivatives 36
Figure 2.7 Antioxidant pyrazole derivatives 36
Figure 2.8 Cholesterol inhibiting pyrazole derivative 37
Figure 2.9 Insecticidal pyrazole derivative 37
Figure 2.10 Antibacterial pyrazole derivative 38
Figure 2.11 Antitubercular pyrazole derivative 38
Figure 2.12 Anticancer pyrazole derivative 38
Figure 2.13 Amine oxidase inhibitor pyrazole derivative 39
Figure 2.14 Antihypertensive pyrazole derivative 39
Figure 2.15 Metal complexes of 1-phenyl-3-methyl-4-benzoyl pyrazole-5-ones 41
Figure 2.16 Pyrazole cyanine dye 41
Figure 2.17 Pyrazole based Disperse Dyes 42
Figure 2.18 Disazo disperse dyes based on 3(2-hydroxyphenyl) 2-pyrazolin-5-ones 42
Figure 2.19 4-arylhydrazono-3(2-hydroxyphenyl) 2-pyrazolin-5-ones based
disperse dyes 43
Figure 2.20 Pyrazoline based tetrakisazo Calix-[4] resorcinarene dyes 44
Figure 2.21 pyrazole and thiadiazole based heterocyclic dyes 44
Figure 2.22 Copper complexes of pyrazole derivatives
44
Figure2.23 Pyrazole based dyes 44
Figure 2.24 Pyrazoles based disperse dyes 45
Figure 2.25 Pyrazoles based Tetrakisazo dyes 45
Figure 2.26 Pyrazoles based Pigments Orange13 (157),
Orange 34 (158) and Red
38(159). 46
Figure 2.27 Pyranopyrazoles based dyes 46
Figure 2.28 Disazo pyrazolo[1,5-a] pyrimidine reactive dyes 47
Figure 2.29 Bifunctional pyrazolo[1,5-a]pyrimidine reactive dyes 47
Figure 4.1 ORTEP diagram of SPMP diazonium Salt 78
Figure 4.2 Crystal packing with hydrogen bonding pattern as dotted lines. H-atoms
not involved are omitted 79
Figure 4.3 FTIR spectrum of 4-sulphophenyl-3-methyl-5-pyrazolone 82
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Figure 4.4 FTIR spectrum of oxime of 4-sulphophenyl-3-methyl-5-pyrazolone. 82
Figure 4.5 FTIR spectrum of diazo-4-sulphophenyl-3-methyl-5-pyrazolone 83
Figure 4.6 UV-Visible Spectra-1 of dyes 201-204 87
Figure 4.7 UV-Visible Spectra-2 of dyes 205-208 89
Figure 4.8 UV-Visible Spectra-3 of dyes 209-212 91
Figure 4.9 UV-Visible Spectra-4 of dyes 213-216
93
Figure 4.10 UV-Visible Spectra-5 of dyes 217-220 95
Figure4.11 UV-Visible Spectra-6 of dyes 221-224 97
Figure 4.12 UV-Visible Spectra-7 of dyes 225-228 99
Figure 4.13 1H-NMR Spectrum of Acid Dye 3c 101
Figure 4.14 13
C-NMR Spectrum of Acid Dye 3c 102
Figure 4.15 UV-Visible Spectra-8 of dyes 229-232 114
Figure 4.16 UV-Visible Spectra-9 of dyes 233-236 116
Figure 4.17 UV-Visible Spectra of dyes 237-240 118
Figure 4.18 UV-Visible Spectra-11 of dyes 241-244 120
Figure 4.19 UV-Visible Spectra-12 of dyes 245-248 122
Figure 4.20 UV-Visible Spectra-13 of dyes 249-252 124
Figure 4.21 UV-Visible Spectra-14 of dyes 253-256 126
Figure 4.22 FTIR Spectrum of Pyrazolone Acid Dye 8g 127
Figure 4.23 FTIR Spectrum Cu (II) complex (7g) of pyrazolone acid dye 8g 127
Figure 4.24 1H-NMR Spectrum of Pyrazolone Acid Dye 8g 129
Figure 4.25 13
C-NMR Spectrum of Pyrazolone Acid Dye 8g 130
Figure 4.26 UV-Visible Spectra-15 of dyes 257-260 141
Figure 4.27 UV-Visible Spectra-16 of dyes 261-264 143
Figure 4.28 UV-Visible Spectra-17 of dyes 265-268 145
Figure 4.29 UV-Visible Spectra-18 of dyes 269-272 147
Figure 4.30 UV-Visible Spectra-19 of dyes 273-276 149
Figure 4.31 FTIR spectrum of Iron complex of dye 18b 161
Figure 4.32 1H-NMR spectrum of ligand acid dye 18b 162
Figure 4.33 13
C-NMR spectrum of ligand acid dye 18b 162
Figure 4.34 UV-Visible Spectra-20 of dyes 277-280 164
Figure 4.35 UV-Visible Spectra-21 of dyes 281-284 166
Figure 4.36 UV-Visible Spectra-22 of dyes 285-288 168
Figure 4.37 UV-Visible Spectra-23 of dyes 289-292 170
Figure 4.38 UV-Visible Spectra-24 of dyes 293-296 172
Figure 4.39 UV-Visible Spectra-25 of dyes 297-300 181
Figure 4.40 UV-Visible Spectra-26 of dyes 301-304 183
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List of Schemes
S.No. Title of Scheme Page No.
Scheme 2.1 Synthesis of 1-Phenyl-3-methyl-2-pyrazoline-5-one from Phenyl
hydrazine and acetoacetic ester 18
Scheme 2.2 Synthesis of 2-pyrazolin-5-ones from substituted hydrazine and β-
ketoester 20
Scheme 2.3 Synthesis of 3-pyrazolin-5-ones from substituted Acetyl phenyl
hydrazine also reacts with β-ketoester and β-ketoester
20
Scheme 2.4
Alkylation of 2-pyrazolin-5-ones with methyl iodide Similarly
symmetrical hydrazines produce 1,2-disubstitued 3-pyrazolin-5-
ones77
21
Scheme 2.5 Synthesis of pyrazolidinones from hydrazines, and ɑ, β-unsaturated
carboxylic acids, esters and amides 21
Scheme 2.6 Synthesis of 5-pyrazolidinediones from hydrazines, and malonic ester
or its acid chlorides 21
Scheme 2.7 Synthesis of pyrazolones from hydrazines, and acetoacetic ester or its
amides 22
Scheme 2.8 Synthesis of pyrazolones from diethyl oxalacetate
90 and aryl
hydrazines 22
Scheme 2.9 Synthesis pyrazolone from acetyl succinic acid or its esters with aryl
diazonium chloride 23
Scheme 2.10 Reaction between Pyrazolones and Ketones 24
Scheme 2.11 Reaction between Pyrazolones and activated aldehyde 25
Scheme 2.12 Reaction between Pyrazolones and Aldehyde 25
Scheme 2.13 Bispyrazolones formation from aryl aldehydes condensation with 1-
phenyl-3-methyl-2-pyrazolin-5-one 26
Scheme 2.14 Aldol condensation reaction of Pyrazolenes with Aldehydes 26
Scheme2.15 C-4 Alkylation of Pyrazolones with Methyl Iodide 27
Scheme2.16 C-4 Alkylation of Pyrazolones with triaryl carbinols 27
Scheme2.17 Synthesis of merocyanine from C-4 Alkylation of Pyrazolones 28
Scheme2.18 C-4 Alkylation of Pyrazolones with acrylonitrile 28
Scheme2.19 N-2 Cyanoethylation of Pyrazolones with Methyl Iodide 29
Scheme2.20 C-4 Acylation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Acetyl
chloride 29
Scheme2.21 C-4 Acylation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Phthalic
anhydride 30
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Scheme2.22 O-Acylation of -pyrazolin-5-ones with benzoyl chloride 30
Scheme2.23 Condensation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with primary
amines 31
Scheme2.24 C-4 nitration of 1-Aryl-3-methyl-2-pyrazolin-5-ones 31
Scheme2.25 C-4 Dinitration of 1-Aryl-3-methyl-2-pyrazolin-5-ones with
Conc.HNO3 32
Scheme2.26 C-4 Sulphonation of 1-Aryl-3-methyl-2-pyrazolin-5-ones 32
Scheme2.27 C-4 Diclorination of 1-Aryl-3-methyl-2-pyrazolin-5-ones 33
Scheme2.28 C-4 Dibromination of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Br2
and NBS 33
Scheme2.29 C-4 nitrosation of 1-Aryl-3-methyl-2-pyrazolin-5-ones 34
Scheme2.30 Oxidative coupling of 3-methyl-1-phenyl-2-pyrazolin-5-one 40
Scheme 2.31 Synthesis of pyrazolone derivative dye, Tartrazine 40
G.Scheme-1 General Scheme-1 for the synthesis of naphthol-AS series of dyes 50
G.Scheme-2 General Scheme-2 for the synthesis of pyrazolone series of dyes 57
G.Scheme-3 General Scheme-3 for the synthesis of naphthol series of dyes 64
G.Scheme-
4a
General Scheme-4a the synthesis of p-subsrtituted Phenol, Resorcinol
and Bisphenol series of dyes(Iron and Copper complexes)
69
G.Scheme-
4b
General Scheme-4b the synthesis of p-subsrtituted Phenol,
Resorcinol and Bisphenol series of dyes(Chromium complexes)
70
Scheme4.1 Synthesis of 4-amino-p-sulphophenyl-3-methyl-5-pyrazolone and its
diazonium salt 77
Scheme 4.2 Synthesis of acid dyes 3a-g and their Fe (II, 5a-g), Cu (II, 6a-g) and
Cr (III, 7a-g) complexes (201-228). 84
Scheme 4.3 Synthesis of acid dyes 8a-g and their Fe (II, 9a-f) and Cu (II, 10a-f)
(229-256). 111
Scheme 4.4 Synthesis of pyrazolone acid dyes 8a-g and their Cr (III, 7a-f)
complex Dyes (229-254). 139
Scheme 4.5 Synthesis of pyrazolone acid dyes 3a-g and their Fe (II, 6a-g), Cu (II,
7a-g) complexes 257-276 159
Scheme 4.6 Synthesis of ligand acid dyes 18a-g and their Fe (II) and Cu (II)
complexes (19a-n, 277-304) 158
Scheme 4.7 Synthesis of ligand acid dyes 18a-g and their Cr (III) complexes
(19o-u, 277-302) 159
G. Scheme General Synthetic Scheme for the synthesis of all dyes
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List of Tables
S.No. Title of Tables Page No.
Table-4.1 X-Ray Crystallographic data of SPMP diazonium Salt Table-4.1 80
Table-4.2 geometric parameters (A
o) of 1-(p-sulphophenyl)-3-methyl-4-
azo-5- pyrazoleoxide 81
Table-4.3 Physical properties of dyes 201-204 86
Table-4.4 Physical properties of dyes 205-208 88
Table-4.5 Physical properties of dyes 209-212 90
Table-4.6 Physical properties of dyes 213-216 92
Table-4.7 Physical properties of dyes 217-220 94
Table-4.8 Physical properties of dyes 221-224 96
Table-4.9 Physical properties of dyes 225-228 98
Table-4.10 Dyeing properties of naphthol-AS series 103
Table-4.11 Physical properties of dyes 229-232 113
Table-4.12 Physical properties of dyes 233-236 115
Table-4.13 Physical properties of dyes 237-240 117
Table-4.14 Physical properties of dyes 241-244 119
Table-4.15 Physical properties of dyes 245-248 121
Table-4.16 Physical properties of dyes 249-252 123
Table-4.17 Physical properties of dyes 253-256 125
Table-4.18 Dyeing properties of pyrazolone dye 131
Table-4.19 Physical properties of dyes 257-260 140
Table-4.20 Physical properties of dyes 261-264 142
Table-4.21 Physical properties of dyes 265-268 144
Table-4.22 Physical properties of dyes 269-272 146
Table-4.23 Physical properties of dyes 273-276 148
Table-4.24 Dyeing properties of naphthol series 150
Table-4.25 Physical properties of dyes 277-280 163
Table-4.26 Physical properties of dyes 281-284 165
Table-4.27 Physical properties of dyes 285-288 167
Table-4.28 Physical properties of dyes 289-292 169
Table-4.29 Physical properties of dyes 293-296 171
Table-4.30 Dyeing properties of p-substituted phenols and resorcinol dyes 173
Table-4.31 Physical properties of dyes 297-300 180
Table-4.32 Physical properties of dyes 301-304 182
Table-4.33 Dyeing properties of bis-phenols dyes 184
Table-4.34 Comparison of the naphthol-AS dye shades with PMS numbers 188
Table-4.35 Comparison of the pyrazolone-pyrazolone dye shades with PMS
number 189
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Table-4.36 Comparison of the naphthol dye shades with PMS numbers. 189
Table-4.37 Comparison of thep-substituted phenol & resorcinol dye shades
with PMS numbers 190
Table-4.38 Comparison of the Bisphenol dye shades with PMS numbers. 190
Table-4.39 Comparison of the dyes with well known National &
International leather dyes. 192
Table-4.40 Comparison of my dyes with well known National &
International leather dyes 193
List of Shade Cards
Shade Card-1 part-a Naphthol-AS Dyes 104
Shade Card-1 part-b Naphthol-AS Dyes 105
Shade Card-2 part-a Pyrazolone dyes 132
Shade Card-2 part-b Pyrazolone dyes 133
Shade Card-3 part-a Naphthol-AS Dyes 151
Shade Card-3 part-b Naphthol-AS Dyes 152
Shade Card-4 part-a p-Substituted Phenol and Resorcinol Dyes 174
Shade Card-4 part-b p-Substituted Phenol and Resorcinol Dyes 175
Shade Card-5 Bis-Phenol Dyes 185
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List of Abbreviations
Abbreviation IUPAC Name
PTMP 3-methyl-1-(4-methylphenyl)-1H-pyrazol-5-ol
PMP 3-methyl-1-(phenyl)-1H-pyrazol-5-ol
Naphthol-ASE 3-hydroxy-N(4-chlorophenyl) naphthalene-2-carboxamide
Naphthol-ASLC 3-hydroxy-N-(4-chloro-2,5-dimethoxyphenyl) naphthalene-
2-carboxamide
H-Acid 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid
Bisphenol-S 4,4'-sulfonyldiphenol
β-Naphthol naphthalen-2-ol
Resorcinol benzene-1,3-diol
SPCP 5-hydroxy-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid
4-nap 2-amino-4-nitrophenol
SPMP 4-(5-hydroxy-3-methyl-1H-pyrazol-1-yl)benzenesulfonic
acid
2,5-diClSPMP 2,5-dichloro-4-(5-hydroxy-3-methyl-1H-pyrazol-1-
yl)benzenesulfonic acid
Naphthol-ASA 3-hydroxy-N-phenylnaphthalene-2-carboxamide
Naphthol-ASD 3-hydroxy-N(2-methylphenyl) naphthalene-2-carboxamide
4-cap 2-amino-4-chlorophenol
4-sap 3-amino-4-hydroxybenzenesulfonic acid
BPA 4,4'-propane-2,2-diyldiphenol
Naphthol-ASPH 3-hydroxy-N(2-ethoxyphenyl) naphthalene-2-carboxamide
Naphthol-ASBS 3-hydroxy-N-(3-nitrophenyl) naphthalene-2-carboxamide
6-napsa 3-amino-4-hydroxy-5-nitrobenzenesulfonic acid
NPJ 4-hydroxy-7-(phenylamino) naphthalene-2-sulfonic acid
PMS Pantone Matching System numbers
Calc. Calculated
C.I. Color Index
CHN Anal. Carbon, Hydrogen and Nitrogen analysis
umd unmetallized dye
Ph Phenyl
Ar Aryl
Conc. concentrated
x
List of Contents
Chapter 1 INTRODUCTION
1.0 Pyrazoles 1
1.1 Applications of Pyrazoles 1
1.1.1 Pharmaceutical Uses 1
1.1.1a Antipyretic and Analgesic 1
1.1.1b Anti-inflammatory action 3
1.1.1C Antimicrobial and Antitubercular Drugs 3
1.1.1d Pyrazole Based Anticancer Agents 4
1.1.1e Antioxidant Drugs 4
1.1.2 Application as Dyes and Pigments 4
1.1.3 Classification of dyes 5
1.1.3a- Classification of dyes by application method 5
1.1.3b Chemical nature based classification of dyes 6
1.1.4 Important classes of dyes based on chemical composition and applications 7
1.1.4a Acid Dyes 7
1.1.4b Azoic Components and compositions 7
1.1.4c- Basic Dyes 7
1.1.4d- Direct Dyes 8
1.1.4e -Disperse Dyes 8
1.1.4f- Fluorescent Brighteners. 8
1.1.4g- Food, Drugs or Cosmetic Dyes. 9
1.1.4h Mordant Dyes 9
1.1.4i Oxidation Bases 10
1.1.4j- Reactive Dyes 10
1.1.4k- Solvent Dyes 10
1.1.4l- Sulfur Dyes 11
1.1.4m- Vat Dyes 11
1.1.5 Pyrazolone Based dyes 11
1.1.5a Pyrazole acid dyes 11
1.1.5b Pyazole disperse dyes 12
1.1.5c Pyrazole Mordant dyes 12
1.1.5d Pyrazole Reactive dyes 12
1.1.5e Pyrazole Metal complex dyes 13
1.1.5f Pyrazole Vat dyes 13
1.1.5g Cationic pyrazole dyes for polyamide fibers 13
1.1.5h Pyrazole dyes used in Color Photography 14
1.1.5j Pyrazole OBAs/FWAs 16
1.1.5i Pyrazole hair dyes 16
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1.1.5j Pyrazole OBAs/FWAs 16
i) Neutral pyrazole OBAs/FWAs 17
ii) Anionic pyrazole OBAs/FWAs 17
iii) Cationic pyrazole OBAs/FWAs 17
Objective of Research 18
Chapter 2 LITERATURE REVIEW
2 Synthesis of pyrazoles 19
2.1 Pyrazoles from hydrazines. 19
2.2 Synthesis of 2-pyrazolin-5-ones. 19
2.3 Synthesis of 3-pyrazolin-5-ones. 20
2.4 Synthesis of pyrazolidinones. 21
2.5 Synthesis of 3, 5-pyrazolidinediones. 21
2.6 Industrial and recent methods of pyrazolones synthesis. 21
2.7 Aryl-3-methyl-2-pyrazolin-5-one. 21
2.8 Aryl-3-corboxy-2-pyrazolin-5-one. 22
2.9 Structure and reactivity of pyrazolones. 23
2.9.1 Tautomerim studies. 23
2.9.2 Condensation reaction of 2-pyrazolin-5-ones. 24
2.9.3 Alkylation reactions of 1-aryl-2-pyrazolin-5-ones. 26
I- Alkylation at C-4. 26
II- Alkylation at N-2 28
2.9.4 Acylation of 1-aryl-2-pyrazoli-5-ones 29
2.9.4a C-4 Acylation. 29
2.9.4b O-Acylation. 30
2.10 Reactions of 2-pyrazolin-5-ones with amines. 30
2.11 Nitration of 1-aryl-2-pyrazolin-5-ones. 31
2.12 Sulphonation of 1-aryl-2-pyrazolin-5–ones. 32
2.13 Halogenation of 1-aryl-2-pyrazolin-5–ones. 33
2.14 Nitrosation of 1-aryl-2-pyrazolin-5–ones. 34
2.15 Synthesis of Pharmacologically active pyrazole derivatives. 34
2.15a Antidepressant Activity. 34
2.15b Antimicrobial pyrazole derivatives. 35
2.15c Antiamoebic pyrazoles. 36
2.15d Antioxidant pyrazole derivatives. 36
2.15e Cholesterol inhibiting pyrazoles. 36
2.15f Insecticidal pyrazole compouds. 37
2.15g Antibacterial pyrazoles. 37
2.15h Antitubercular pyrazole derivatives. 38
2.15i Anticancer pyrazole compounds. 38
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2.15j Amine Oxidase Inhibiting pyrazoles. 39
2.15k Antihypertensive pyrazole derivatives. 39
2.15l Oxidation of pyrazoles. 39
2.16 Synthesis of 1-aryl-2-pyrazolin-5–ones dyes. 40
2.17 Synthesis of 1-aryl-2-pyrazolin-5–one Pigments. 45
2.18 Condensed pyrazoles with other heterocyclics and their dyes. 46
2.18a Pyranopyrazoles and their dyes. 46
2.18b Pyrazolopyrimidines and their dyes. 47
Chapter 3 EXPERIMENTAL
3.1 Equipment used: 48
3.2 Instruments used: 48
3.3 Synthesis of diazonium compound of SPMP 49
3.3.1 Nitrosation of SPMP 49
3.3.2 Reduction of Nitroso derivative to amine 49
3.3.3 Diazotization 49
3.4 General Scheme-1 for the Synthesis of naphthol-AS series of dyes 50
3.4.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP) 50
3.4.2 Diazotization and Coupling with Naphthol AS Couplers 51
3.4.3 Metallization of naphthol-AS Acid Dyes 51
3.5 General Scheme-2 for the Synthesis of pyrazolone series of dyes 57
3.5.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP) 57
3.5.2 Diazotization and Coupling with Pyrazolones: 57
3.5.3 Metallization of Pyrazolone Acid Dyes 58
3.6 General Scheme-3 for the Synthesis of Naphthol series of dyes 63
3.6.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP) 64
3.6.2 Reduction 64
3.6.3 Diazotization 64
3.6.4 Coupling 65
3.6.5 Metallization of naphthol acid dyes 65
3.7 General Scheme-4 for the Synthesis of p-substituted-Phenol, Resorcinol
and Bisphenol Dyes. 69
3.7.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP) 70
3.7.2 Diazotization and Coupling with Phenol Derivatives 71
3.7.3 Metallization of phenolic Acid Dyes. 71
Chapter 4 RESULTS AND DISCUSSION
4.1 Synthesis of 4-amino-1-(p-Sulphophenyl)-3-methyl-5-pyrazolone and its
diazonium Salt 77
4.2 Nitrosation, Reduction and Diazotization of SPMP 77
4.3 Synthesis of Naphthol-AS Series of Dyes 83
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4.3.1 Naphthol-ASA dyes 85
4.3.2 Naphthol-ASBS dyes. 87
4.3.3 Naphthol-ASD Dyes. 89
4.3.4 Naphthol-ASE Dyes. 91
4.3.5 Naphthol-ASLC Dyes 93
4.3.6 Naphthol-ASOL Dyes. 95
4.3.7 Naphthol-ASPH dyes. 97
4.4 Spectral properties of Naphthol-AS dyes 99
4.5. Dyeing properties of Naphthol-AS dyes. 102
4.6 Synthesis of Pyrazolone series of dyes. 110
4.6.1 SPMP dyes. 112
4.6.2 SPCP Dyes. 114
4.6.3 PMP Dyes. 116
4.6.4 4.5.4 PTMP dyes. 118
4.6.5 3-SPMP dyes. 120
4.6.6 3-ClPMP Dyes. 122
4.6.7 2,5-diClSPMP Dyes 124
4.7 Spectral Properties of Pyrazolone Dyes 126
4.8 The Dyeing Properties of Pyrazolone Dyes. 130
4.9 Synthesis of Naphthol Series of Dyes. 138
4.9.1 β-Naphthol dyes. 139
4.9.2 Schaeffer’s acid Dyes. 141
4.9.3 R-Acid dyes. 143
4.9.4 H-Acid Dye. 145
4.9.5 N-Phenyl J. Acid dyes. 147
4.10 The Dyeing Properties of Naphthol Dyes 149
4.11 Synthesis of p- Substituted-Phenols, Resorcinol and Bis-Phenol series of
dyes. 157
4.11.1 p-Chlorophenol dyes. 162
4.11.2 p-Nitrophenol dyes. 164
4.11.3 Phenol-4-sulphonic acid dyes. 166
4.11.4 2-Nitro-4-sulphophenol dyes. 168
4.11.5 Disazo Resorcinol Dyes. 170
4.12 The Dyeing Properties of p-Substituted Phenols and Resorcinol Dyes 172
4.13 Synthesis of Bisphenol Dyes. 179
4.13.1 Bisphenol-S Dyes. 180
4.13.2 Bisphenol-A Dyes. 182
4.14 The Dyeing Properties of Bis-Phenol Dyes 183
xiv
4.15 Comparison of Shades of Present Work Dyes With National and
International Standards. 188
4.15A- Comparison with Pantone Matching System. 188
4.15B- Comparison with well known Leather Dyes. 190
SUMMARY 194
i- naphthol-AS series 194
ii- pyrazolone series 194
iii- naphthol series 194
iv- p-substituted phenol series 195
v- bisphenol series(BPS-dye shown, where Ar- is( p-sulfophenyl group) 195
FUTURE PROSPECTS. 198
1
Chapter 1 INTRODUCTION
1. Pyrazoles
Among heterocyclic compounds pyrazole and its derivatives have a unique part of utilization.
Their applications revolve around their consumption in Pharmaceutical, Agricultural, Dyes and
Pigments, Photography, Analytical Chemistry and even personal care utilities also contain some
sort of pyrazole based additives. Pyrazolones, the hydroxypyrazoles are of three major classes,
each having several Tautomeric forms: 3-pyrazolin-5-one (1); 2-pyrazolin-5-one (2); and. 4-
pyrazolone, also called 2-pyrazolin-4-one (3) Within each class of pyrazolones many tautomers
are possible; for simplicity only one form is shown below.
Figure 1.1; Tautomeric forms of hydroxypyrazoles (1-3)
1.1 Applications of Pyrazoles
1.1.1 Pharmaceutical Uses
Pyrazoles and their derivatives have eminent position regarding pharmaceutical applications
including their usage as antipyretics, analgesics, anti-inflammatory, antifungal, anticancer,
antibacterial and anti-tubercular drugs which are discussed as
1.1.1a Antipyretic and Analgesic
Several compounds with these activities are known. A few are mentioned here with their
Chemical, Medicinal name (Trade name) and structures. Antipyrin (Phenazone) 2, 3-dimethyl-
1-phenyl-5-pyrazolone (Figure1.2), has both Antipyretic and Analgesic activities
1,2.
Figure 1.2; Phenazone; an Antipyretic and Analgesic.
2
Another Antipyrin analogue known as Aminopyrin (Pyrimidon), 4-Dimethylamino-1,5-
dimethyl-2-phenylpyrazol-3-one (Figure 1.3) has been found to be more active than the parent
compound.3
Figure 1.3; Pyrimidon, 4-Dimethylamino-1,5-dimethyl-2-phenylpyrazol-3-one.
The activity of Aminopyrin in Rheumatic fever has been found to be equal to
Salicylates4.Similarly among pyrazole derivatives, Butazolidin (Phenylbutazone) 4-butyl-1,2-
diphenyl-pyrazolidine-3,5-dione2 (Figure 1.4)
has been extensively used as for a long time to
cure various rheumatoid arthritis conditions and in this regards Hemming and Kuzell5 have
published a review.
Figure 1.4; Pyrazole derivative, Butazolidin, used to cure rheumatoid arthritis.
Recently Tulunay et al6., have studied the Efficacy and Safety of Dipyrone
and found to be very
effective in migraine treatment. Dipyrone (Novalgin), which is, Sodium 1-phenyl-2,3-dimethyl-
5-pyrazolone-4-methylamino-methylsulfonate (Figure 1.5).
Figure 1.5; Sodium 1-phenyl-2,3-dimethyl-5-pyrazolone-4-methylamino-methylsulfonate.
3
1.1.1b Anti-inflammatory action
A large literature exists about Anti-inflammatory activity of various pyrazolones, however ,
Amir and Kumar 8 have synthesized different pyrazoles for anti-inflammatory and other
biological activities. Moreover Samir et al.9 have recently reported synthesis of 4-[5-(4-
methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene sulfonamide (4) and 4-[5-(4-
bromophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene sulfonamide (5) as potential anti-
inflammatory agents (Figure 1.6).
Figure 1.6; Pyrazolone derivatives used as anti-inflammetry drugs.
1.1.1d Antimicrobial and Antitubercular Drugs
Several pyrazole derivatives have been found to possess antimicrobial and antitubecular activity
(Figure 1.7). A vast literature exists, however, work by Shelke et al10
., Joshi et.al11
and
Sammaiah et al12
is of particular interest.
O
N NH
OH
OH
OHNH3
+
O
O
CF3
-O
Figure 1.7; Pyrazole C-glycoside pyrazofurin; 4-hydroxy-3-β-D-ribofuranosyl 1H-pyrazole-5-
carboxamide.
4
1.1.1d Pyrazole Based Anticancer Agents
Many pyrazole derivatives, especially pyrazole 5-ones derivatives have found utilization as
Cancer controlling agents and possess anti-tumor activity for example, thiadiazole substituted
pyrazole -5-one (Figure1.8)13
.
Figure 1.8; Thiadiazole substituted pyrazole -5-one as anti-cancer drug.
Similarly another pyrazole derivative, 4,4-dichloro-1-(2,4dichlorophenyl)-3methyl-5-one
(Figure 1.9)14
and many other have been found to be a very effective Cancer treatment
agent15-16
.
Figure 1.9; Pyrazole derivative, 4,4-dichloro-1-(2,4dichlorophenyl)-3methyl-5-one an anti-
cancer drug.
1.1.1e Antioxidant Drugs
Several pyrazole derivatives have been found to be good antioxidants. Umesha et al.17
have
synthesized and characterized many pyrazole compounds for their antioxidant and antimicrobial
activity.
1.1.2 Application as Dyes and Pigments
A large number of pyrazole derivatives are utilized as Dye Intermediates for the synthesis of
several types of Dyes and Pigments; hence it will be better to discuss in detail.
Dyes are intensely colored materials used for coloration of substrates like cotton, paper, nylon,
leather, plastics, hair, foods and many other human utilities. In fact a dye is a colour that
5
distributes itself up to molecular level in its substrate. These may be retained in the substrate by
various phenomena like adsorption, salt formation and metal complex formation or even
sometimes by covalent bond formation.
A dye usually consists of two types of groups which are chromophores (– NO, -NO2, -N=N, -
C=C-, -C=O) and auxochromes (-OH, -SO3H, -NH2, -NHR, -NR2. –SO2NH2, -CO-CH3, -CH=O)
The most comprehensive information source about dyes is Color Index18
, which is a joint
venture of American Association of Textile Chemists and Colorists (AATCC) and Society of
Dyers and Colorists (SDC) UK. Color index is a 10 volume monograph published annually with
several supplement volumes published periodically. As an example of information from this
source, Tartrazine (Figure 1.10)19
is presented which is a pyrazolone dye.
Figure 1.10; Tartrazine, pyrazolone based dye.
1.1.3 Classification of dyes
Dyes are classified in two ways depending upon their application method and chemical
composition (Constitution).
1.1.3a- Classification of Dyes by Application Method
This type of classification of dyes is favorite for end users and includes the dyes which are
represented in Figure 1.11.
6
Figure 1.11; Flow sheet diagram for classification of dyes based on their Application.
1.1.3b-Chemical Nature Based Classification of Dyes
This classification system is favourite for dye manufacturers and scientist21
. According to the
chemical nature/chemical structure dyes are;
Dyes Chemical Constitution
Nitroso Dyes
Nitro Dyes
Azo Dyes
Azoic Dyes
Stilbene Dyes
Diphenyl methane Dyes
Triaryl methane Dyes
Xanthene Dyes
Acridine Dyes
Quinoline Dyes
Methine Dyes
Thaizole Dyes
Indaine Dyes
Azine Dyes
Oxazine Dyes
Thaizine Dyes
Anthraquinone DyesIndigo Dyes
PhthalocyanineAminoketone Dyes
Figure 1.12; Flow sheet diagram for classification of dyes based on their constitution.
7
1.1.4 Important Classes of Dyes Based on Chemical Composition and Applications
1.1.4a-Acid Dyes
Acid dyes are mainly used for nylon, wool, silk, paper, inks and leather. They are usually applied
from neutral to acidic bath. These may be azo, azometal complex, anthraquinone, nitro & nitroso
etc. An example of acid dye of nitroso type is C. I. Acid Green 1(Figure1.13)22
.
Figure 1.13; Acid Metal complex
1.1.4b-Azoic Components and compositions
The word Azoic is derived from [Azo + ice], as these dyes are formed inside the substrate on
molecular level. Substrates are cotton, rayon, cellulose acetate and polyester. Fiber is
impregnated with a coupler and later on treated with a solution of stabilized diazonium salt to
develop color.
1.1.4c-Basic Dyes
Basic dyes find their application in paper, polyacrylic, polyacrylonitrile, polyester and inks
etc.They are applied from acidic dye bath. Chemically these may be cyanine, diarylmethane, azo,
azine, acridine, oxazine and anthraquinone etc. These are also called cationic dyes for example
C.I. Basic Yellow 2 (Figure1.14)23
, a diarylmethane type dye.
Figure 1.14; Basic Yellow 2, a diarylmethane dye.
8
1.1.4d-Direct Dyes
As the name indicates these dyes are applied to substrates directly from their bath. The most
common substrates are cotton, paper, leather and nylon etc. Chemically these may be Azo,
phthalocyanine, Stilbene and oxazine etc. An example of this type is C.I. Direct Black 78
(Figure 1.15)24
, a trisazo dye.
Figure 1.15; C.I. Direct Black 78
1.1.4e-Disperse Dyes
These dyes are applied as fine aqueous dispersions from their bath at an elevated temperature or
at a lower temperature with the help of carriers. The usual substrates are polyester, polyamide,
acrylics, acetate and plastic. Chemically these may be azo, anthraquinone, nitro, styril etc. C.I.
Disperse Blue 19 (Figure 1.16)25
is an example of Anthraquinone dyes.
Figure 1.16; Anthraquinone dye; C.I. Disperse Blue 19
1.1.4f- Fluorescent Brighteners.
These are also called Fluorescent Whitening Agents (FWA’s), Optical Brightening Agents
(OBA’s) and find their application in a variety of substrates like oils, paints, plastics, soaps,
detergents and all fibers. They are applied from their solutions, dispersions or suspentions in a
process. Chemically they may be stilbene, pyrazolones, coumarins, naphthalimides and
imidazoline etc. Brightener Ultraphore WT (Figure 1.17)26
is an example of imidazoline
derivative.
9
Figure 1.17; Fluorescent Brighteners imidazoline derivative.
1.1.4g- Food, Drugs or Cosmetic Dyes.
As the name indicates, these dyes are produced under very strict vigilance and control.
Chemically these may be azo, anthraquinone, carotenoids, and triaryl methane type. C.I. Food
Red 3 (Figure 1.18)27
is an example of azo dye.
Na+
N NS
O
O
-O
OH
SO3
- Na
+
Figure 1.18; C.I. Food Red 3.
1.1.4h-Mordant Dyes
These dyes are applied to wool, leather and anodized aluminum with the help of a mordant like
Al, Cr Salts. Chemically they may be azo and anthraquinone type. C.I. Mordant Red 7
(Figure1.19)28
is an example of azo dye obtained by after chroming process.
N
N
OH
N N SO3
- Na
+
OH
CH3
Figure 1.19; C.I. Mordant Red 7.
1.1.4i-Oxidation Bases
These find application on hair, fur and cotton. The process consists of oxidation of aromatic
amine and phenols on the substrate. Chemically these may be anilines, phenylenediamines,
10
amino phenols reacted (oxidized) with primary intermediate to impart color. Following reaction
is an example of Oxidation base, Indamine Blue (8) 29
dye (Figure 1.20).
Figure 1.20; Oxidation base, Indamine Blue Hair Dye
1.1.4j-Reactive Dyes
These dyes are applied to cotton, wool, silk and nylon. They react with functional group
substrate to form covalent bond. The process requires higher pH (8.5-9.5) and heat (temperature
65-125°C). Chemically these may be azo, anthraquinone, phthallocyanine, formazan, basic and
oxazine. Color Index Reactive Red 130
is an example of azo reactive dye (Figure1.21).
Figure 1.21; H-acid based Reactive Dye.
1.1.4k-Solvent Dyes
Solvent dyes find their application in plastics, gasoline, varnishes, lacquers, inks, fat oils and
waxes. They form solution in the substrate. Chemically they may be azo, triphenylmethane,
anthraquinone and phthalocyanine C.I. Solvent Violet 1331
is an example of anthraquinone type
solvent dye (Figure 1.22).
Figure 1.22; Anthraquinone type Solvent dye.
11
1.1.4l-Sulfur Dyes
These are the derivative of sulfur applied to cotton and rayon. They are usually produced on the
substrate by padding with aromatic components and sodium sulfide, oxidation of the padded
substrate result into color formation. However due to environmental problem the sulfur dyes are
being obsolete.
1.1.4m-Vat Dyes
As the name indicates, these dyes are produced in vats and applied to cotton, wool and rayon.
These are water insoluble and are reduced to soluble Leuco vats with sodium sulfite and oxidized
to original color by oxidation. Chemically these may be anthraquinone and indigoids. C. I. Vat
Orange 332
is an example of Anthraquinone type dye (Figure1.23).
Figure 1.23; Anthraquinone type Vat dye
1.1.5 Pyrazolone Based dyes
Pyrazolone dyes are of great industrial importance. A vast literature exists however a few are
exemplified as under.
1.1.5a Pyrazole acid dyes
As an example of Prazolone acid dyes, C.I. Acid yellow 2733
(Constitution #19130) is shown
in Figure 1.24.
Figure 1.24; Pyrazole based Acid Dye.
12
1.1.5b Pyazole disperse dyes
Out of Prazolone disperse dyes, Disperse Yellow 60 (10)34
(Constitution #12714) is shown
below. Among Food Dyes pyrazolone yellow are well known. As an example Food Yellow
4(11)35
(constitution #19140) is presented in figure 1.25.
Figure 1.25; Pyrazole based Disperse Dye.
1.1.5c Pyrazole Mordant dyes
Pyrazolones also find their application in Mordant dye preparation. C. I. Mordant Orange 3736
(constitution #18730) is an example of pyrazole based mordant dyes (Figure 1.26)
Figure 1.26; Pyrazole based Mordant Dye.
1.1.5d Pyrazole Reactive dyes
Many pyrazolone reactive dyes are being used industrially. Most of these are patented. Reactive
Yellow 237
(constitution #18972) is an example of this type (Figure 1.27)
Figure 1.27; Pyrazolone based Reactive Dye.
N
N
COO- Na
+
OH
N N SO3
- Na
+
-O3SNa
+
N
N
OH
N N
O
O
CH3CH3
10 11
13
1.1.5e Pyrazole Metal complex dyes
Among the pyrazolone dyes perhaps metal complex dyes are of the most interest due to their
light fastness and levelness. C.I. Acid Orange 9238
(constitution #12714) being a 2:1 chromium
complex is presented as an example of this type dye (Figure 1.28).
Figure 1.28; Pyrazolone based Metal Complex Dye.
1.1.5f Pyrazole Vat dyes
Pyrazole has found utilization in vat dyes as well. C. I. Vat Blue 25 (constitution # 70500)
(12)38
is an example of a vat dye derived from 3-pyrazoloanthronylbenzanthrone. Similarly
C.I.Vat Red 13 (constitution#70320) (13)39
is another example of a Vat dye obtained from
anthrapyrazole (Figure 1.29).
N
O
N
O CH3CH3
NNH
O
N
O
NH
1312
Figure 1.29; Pyrazole based Vat Dyes.
1.1.5g Cationic pyrazole dyes for polyamide fibers
Several cationic pyrazole dyes are commercially important. The major use of these is in acrylic
fibers, leather and paper as well. Dye (14)40
is applied to leather and paper to get a clear orange
shade. Similarly brilliant and clear yellow shade are obtained with Cationic dye (15)41
when
applied to leather and paper. Still another interesting light fast blue shade is obtained on
14
Acrylonitrile with Cationic Dye (16)42
and clear Reddish Orange shade is obtained by Cationic
Dye (17)43
on the same substrate (Figure 1.30).
Figure 1.30; Pyrazolone based cationic dyes used for polyamide fibers.
1.1.5h Pyrazole dyes used in Color Photography
Perhaps the latest and most frequent use of pyrazole dyes is in Color photography. In this field
pyrazole dyes are used in several ways including filters, photo sensitizers and photodvelopers or
simply as couplers. Dye (18)44
is an example of a photo sensitizer and chemically it is an Oxanol
type of a pyrazole dye. Similarly a combination of Oxanol type dye (19)45
and (20)45
is used as a
filter that absorbs the visible light completely (Figure 1.31).
15
Figure 1.31; Oxanol and oxanol derivatized dyes used in Photography.
Another achievement was made by the synthesis of 1-Aryl-5-pyrazolone Magenta couplers
having a special Photographically Useful Leaving Groups (PULG) at the coupling position of
pyrazolone as shown below (21)46
. Later on many modifications have been done in this field
having pyrazole moiety for example 1-H (3, 2-C)1,2,4-triazole Couplers as shown below
(22) 47-51
(Figure 1.32).
16
Figure 1.32; Pyrazolone and Triazole based dyes with PULG.
1.1.5i Pyrazole hair dyes
For the preparation of hair dyes many pyrazole derivatives have been frequently used. Among
these 4,5-diamino-1-methyl pyrazole (23) is the most commonly used as an Oxidation Base with
various Couplers (24-26) to produce different colours as shown below52-54
(Figure 1.33)
Figure 1.33; Pyrazole based Hair Dyes.
1.1.5j pyrazole OBAs/FWAs
Pyrazole based Optical Brightening Agents (OBAs) and Fluorescent Whitening Agents (FWAs)
are materials of special interest for Industrial use. Depending upon their ionic character these are
classified into neutral, anionic and cationic types.
17
i) Neutral pyrazole OBAs/FWAs
These OBAs are commonly used for brightening Polyamide fibers and have very high brilliancy;
however these have moderate light and Bleach fastness properties. Fluorescent Whitening Agent
121 (27)55
and Fluorescent Whitening Agent 51 (28)56
are presented as examples of neutral
pyrazoline OBAs/ FWAs (Figure 1.34).
Figure 1.34; Neutral Fluorescence Whitening Agents.
ii) Anionic pyrazole OBAs/FWAs
These OBAs can be used for whitening of cellulosic and polyamide materials .Fluorescent
Whitening Agent 52 (29)57
and Fluorescent Whitening Agent 53 (30)58
are examples of Anionic
Pyrazoline OBAs/FWAs (Figure 1.35).
Figure 1.35; Anionic Fluorescence Whitening Agents.
iii) Cationic pyrazole OBAs/FWAs
Like neutral and anionic pyrazole OBAs, cationic OBAs are also frequently used for
Polyacrylonitrile and cellulose acetate. These OBAs are very bright with moderate light fastness.
Fluorescent Whitening Agent 56 (31)59
and Fluorescent Whitening Agent 5 (32)60
are shown as
examples here (Figure 1.36)..
Figure 1.36; Cationic Fluorescence Whitening Agents.
18
Objectives of Research
It is well known fact that dyes have very economical and commercial importance. Dyes
manufacturing industries are not well developed in our country due to the fact, most of the
industrial products are concealed and patented. The purpose of this research work is to
synthesize new derivatives of pyrazole and their dyes, having a commercial importance. This
illustrative work will be beneficial for the development of new industrial products and this will
help in import substitution and save foreign exchange. This indigenous development of new
pyrazole based dyes will also open a new era of research work for the growth of countries
economy and industrialization. Keeping in view the importance of dyes our objectives include
The synthesis of a series of new pyrazole derivatives capable of forming dyes including
amine components (active components) as well as new coupling components.
Application of dyes on suitable substrates and evaluation of their substantive properties.
Comparative study of dyes with existing standards of unknown chemistry.
Study of new pyrazole dyes for their chemical structures and stability against the
environmental factors.
19
Chapter 2 LITERATURE REVIEW
Pyrazole was synthesized by Knorr61
in 1833 by the reaction of acetoacetic ester (33) and
phenylhydrazine (34) although at that time the correct structure was not known. The exact
structure was also determined by Knorr62
in 1887 and the name ―Pyrazole‖ was suggested by
Ruhemann63
. Actually this product was 1-Phenyl-3-methyl-2-pyrazoline-5-one (35) as shown
below (Scheme 2.1).
Scheme 2.1; Synthesis of 1-Phenyl-3-methyl-2-pyrazoline-5-one from Phenyl hydrazine and
acetoacetic ester
2 Synthesis of pyrazoles
The synthesis of pyrazole and its derivatives is a very vast field. The details can be found in
literature64
.A few methods showing the synthesis of various pyrazoles, are presented here.
2.1 Pyrazoles from hydrazines.
This is the most primitive method of pyrazoles synthesis and is still being used by many
scientists. The nature of hydrazine and 2nd
component to be used depends on the nature of the
product needed. Hence the methods given here are based on the nature of pyrazole needed as the
product.
2.2 Synthesis of 2-pyrazolin-5-ones.
These have been synthesized by the reaction of appropriate hydrazines with β-ketoester65-68
or
amides 69-71
to give 2-pyrazolin-5-ones as shown by following general reaction Scheme 2.2.
20
Scheme 2.2; Synthesis of 2-pyrazolin-5-ones from substituted hydrazine and β-ketoester.
2.3 Synthesis of 3-pyrazolin-5-ones.
Acetyl phenyl hydrazine also reacts with β-ketoester72-74
to form 3-pyrazolin-5-ones by the loss
of acetyl group as shown below (Scheme 2.3).
Scheme 2.3; Synthesis of 3-pyrazolin-5-ones from substituted Acetyl phenyl hydrazine also
reacts with β-ketoester and β-ketoester.
Similarly 3-pyrazolin-5-ones have been made by Alkylation of 2-pyrazolin-5-ones using methyl
iodide75
or dimethylsulfate76
as an alkylating agent especially to produce Antipyrine as shown
below (Scheme 2.4).
Antipyrine
N
NCH3
O
+ CH3 I N
NCH3
O
CH3
Scheme 2.4; Alkylation of 2-pyrazolin-5-ones with methyl iodide.
Similarly symmetrical hydrazines produce 1, 2-disubstitued 3-pyrazolin-5-ones77
.
21
2.4 Synthesis of pyrazolidinones.
Hydrazines have been also used to produce pyrazolidinones from a number of reactants like
α, β-unsaturated carboxylic acids78
, esters79-80
and amides81
to get the requisite products as shown
below (Scheme 2.5).
R1
R2
R3
O
NH
R4 +NH
R5NH2 NNH
R5
R1
R2 R3
O
43
3744
Scheme 2.5; Synthesis of pyrazolidinones from hydrazines, and α,β-unsaturated carboxylic
acids, esters and amides.
2.5 Synthesis of 3, 5-pyrazolidinediones.
Reactions of malonic ester or its acid chlorides82-84
with hydrazines were used to synthesize 3,5-
pyrazolidinediones shown as under (Scheme 2.6).
O
X
R1
O
X+ NH
R3NHR2
NN
R3
R1
O
O
R2
45
46
47
Scheme 2.6; Synthesis of 5-pyrazolidinediones from hydrazines, and malonic ester or its acid
chlorides.
2.6 Industrial and recent methods of pyrazolones synthesis.
Several pyrazolones have been synthesized industrially. Synthesis of a few is discussed as under
2.7 Aryl-3-methyl-2-pyrazolin-5-one.
In industrial processes these pyrazolones are being synthesized by the reaction of aryl hydrazines
and acetoacetic ester or its amides in solvents like acetic acid85-87
, glycerin88
or even ehtanol89
22
has been used as shown below (Scheme 2.7).
X
O
CH3
O
+ NH
NH2Ar-H2O, -HX
H
NN
OH
Ar
CH3
Where X= OR, NH2
48 49
50
Scheme 2.7; Synthesis of pyrazolones from hydrazines, and acetoacetic ester or its amides.
2.8 Aryl-3-corboxy-2-pyrazolin-5-one.
Recently these pyrazolones are being manufactured by the reaction of diethyl oxalacetate90
and
aryl hydrazines, indicated as under (Scheme 2.8).
H5C2OOC2H5
O
O O
+ NH2
NH
Ar N
N
HOOC
O
Ar
After hydrolysis
49
51 52
Scheme 2.8; Synthesis of pyrazolones from diethyl oxalacetate90
and aryl hydrazines.
Similarly another route of this synthesis is the use of acetyl succinic acid91
or its esters with aryl
diazonium chloride as shown below (Scheme 2.9).
OHOC2H5
O
OCH3 O
+ NN+
Ar NN
HOOC
O
Ar
Cl-
NaOH
5253
54
Scheme 2.9; Synthesis of pyrazolone from acetyl succinic acid or its esters with aryl diazonium
chloride.
23
2.9 Structure and reactivity of pyrazolones.
It has been found since long that pyrazolones are very reactive64
.This is mainly due to the
presence of two hydrogens at C-4 position. Manny studies have been conducted on pyrazolones
especially on 1-aryl-2-pyrazolin-5-ones; a brief review is given here.
2.9.1 Tautomerism studies.
Tautomerism of pyrazolones is a very interesting and challenging aspect of pyrazolone
structure. Several scientists have worked to reveal the tautomeric structures by the application of
latest instrumental techniques. This interesting structural field was even elaborated by Knorr
himself and he synthesized three types of tautomeric pyrazolones as early as 189592
. These are
enol-form (OH form), keto-hydrazone (CH form) and Keto-hydrazine (NH form) as depicted
below (Figure 2.1).
NN
OH
R
X Y
NN
O
R
X Y
NHN
O
R
X Y
Enol form(OH form) Ketohydrazone form(CH form) Ketohydrazine form(NH form)
55 56 57
Figure 2.1; Different Tautomeric forms of Pyrazolones.
Later on extensive studies were conducted by Katritzky93-96
and Elguero97-100
using U.V, I.R.
and NMR spectroscopic techniques to determine tautomerism of pyrazolones. Similarly Hawkes
et al101
. and Elguero et al102
have also studied pyrazolone tautomerism using13
C and 15
N for
NMR Spectroscopy. Among tautomeric forms of pyrazolones, 4-arylazo dyes and pigments
(Figure 2.2) offer the most interesting 4- tautomeric forms 58A-D. Among these, B and C forms
have been found to be the dominant ones as investigated by several scientists103-111
.
24
N
NPh
R
N
N Ar
O H
N
N
O
Ph
R
NH
N Ar
H
H
NN
O
Ph R
N
N
Ar
H
H
58 - B 58 - C 58 - D
----- ----
58 - A
N
N Ar
N
N
O
Ph
R
Figure 2.2; Four Tautomeric forms of substituted Pyrazolones.
2.9.2 Condensation reaction of 2-pyrazolin-5-ones.
This molecule readily reacts by its hydrogen at C4 with several reactants especially aldehydes
and ketones113
. As a result of this condensation a mixture of mono and bis-pyrazolone products
were found to be formed as studied by a number of scientists114-119
and is illustrated below
(Scheme 2.10).
NN
O
R2
R1
R3
R4
O
NN
O
R2
R1
R3
R4N
N
O
R2
R1R3
R4
N
N
O
R2
R1
+ +
59 60 6162
Scheme 2.10; Reaction between Pyrazolones and Ketones.
Many scientists have found that very reactive aldehydes like formaldehyde120
and chloral121-122
on condensation with pyrazolones do not afford dehydration products but only methylols are
formed as shown in Scheme 2.11.
25
NN O
R1
OHR2
NN
O
R1
R2
+H
H
O
NN
O
R1
R2
+OCl
Cl
ClH
NN O
R1
R2
OH
Cl
Cl
Cl
59
59
6364
65 66
Scheme 2.11; Reaction between Pyrazolones and activated aldehyde.
Similarly initially it had been found that aryl aldehydes did not give bispyrazolone as a
condensation product123
but this is contrary to the recent research. Several scientists have found
Knoevengel type condensation of aryl aldehydes with 1-phenyl-3-methyl-2-pyrazolin-5-one,
using MgO124
, LiBr125
and triethanolamine126
in ethanol as a catalyst as shown below (Scheme
2.12).
NN
Ph
CH3
O + Ar
O
H
NN
Ph
CH3
O
H
ArCatalyst
6768
35
Scheme 2.12; Reaction between Pyrazolones and Aldehyde.
Another approach for above reaction was the use of microwave irradiation by Li et al127
., and
Dandia et al128
.
In a more recent research by a number of scientists non catalytic129-133
long time and catalytic
experiments134-139
have supported the primitive idea of bispyrazolones formationas a result of
aryl aldehydes with 1-phenyl-3-methyl-2-pyrazolin-5-one as expressed below (Scheme 2.13).
26
NN
Ph
CH3
O + Ar
O
H
N
NPh
CH3
O
Ar
H
N
NPh
CH3
O
No Catalyst, 27 - 36 h
35
67
69
Catalyst, 2 - 3 h
Scheme 2.13; Bispyrazolones formation from aryl aldehydes condensation with 1-phenyl-3-
methyl-2-pyrazolin-5-one.
Another interesting reaction of 1-aryl-2-pyrazolin-5-ones is condensation with amides especially
Formamide140-142
at C-4 position. This is an aldol condensation followed by dehydration step as
well. The reaction proceeds at an elevated temperature143
as shown below (Scheme 2.14).
NN
R2
O
R1
H
NH
O
R3
+160 - 220 oC
NN
R2
O
R1
NHR3
59
70
71
Scheme 2.14; Aldol condensation reaction of Pyrazolines with Aldehydes.
2.9.3 Alkylation reactions of 1-aryl-2-pyrazolin-5-ones.
Alkylation reactions of 1-aryl-2-pyrazoli-5-ones take place easily at C-4 and N-2 as well with
various alkylating agents like alkyl halides. These alkylation reactions also proved its tautomeric
strucres indicating two types of tautomerism.
I- Alkylation at C-4 indicates CH form.
II- Alkylation at N-2 indicates NH form.
I- Alkylation at C-4.
C-4 Alkylation of pyrazolones depends on the nature of alkylating agent and the reaction
conditions as well, as indicated by 3-methyl-1-phenyl-2-pyrazolin-5-one. Knorr62
found the
27
formation of dialkyl derivative proceeding through a mono substituent as indicated below. This
is alkoxide dependant, hence called Alkoxide effect62
(Scheme 2.15).
CH3I
NaOCH3
CH3I
NaOCH3
NN
CH3
O
Ph
NN
CH3
O
CH3
Ph
NN
CH3
O
CH3
CH3
Ph
35 72 73
Scheme 2.15; C-4 Alkylation of Pyrazolones with Methyl Iodide.
It has been found that many triaryl carbinols and ethers of these carbinols react with 3-methyl-1-
phenyl-2-pyrazolin-5-one to give C-4 alkylation145-146
products. More over orthoesters147-148
also
furnish the same derivatives as shown below (Scheme 2.16).
NN
CH3
O
Ph
+ R1C(OR2)3 NN
CH3
O
Ph
R1
OR2
35
74
75
Scheme 2.16; C-4 Alkylation of Pyrazolones with triaryl carbinols.
The most important feature of C-4 alkylation is the synthesis of countless number of
merocyanine149-151
dyes. Dyes 77 and 79 are two examples of such dyes formed by two different
condensing agents with 3-methyl-1-phenyl-2-pyrazolin-5-one as shown in Scheme 2.17.
28
NN
CH3
O
Ph
+S
N+
S
Ph
C2H5
X-
N
N
O
PhN
S
CH3
C2H5
77
NN
CH3
O
Ph
+S
N+
R1
S
R2
X-
79
35
35
76
78
N
N
O
Ph
R2
S
N
R1
CH3
Scheme 2.17; Synthesis of merocyanine from C-4 Alkylation of Pyrazolones.
In the same way 3-methyl-1-phenyl-2-pyrazolin-5-one undergoes cyanoethylaion at C-4 by the
reaction of acrylonitrile152
as shown below (Scheme 2.18).
NN
CH3
O
Ph
+CH2
CN
N
N
O
Ph
CH3
CN
CN
2
35
80
81
Scheme 2.18; C-4 Alkylation of Pyrazolones with acrylonitrile.
II- Alkylation at N-2
In the absence of NaOCH3, alkylation of 3-methyl-1-phenyl-2-pyrazolin-5-one with R-I results
in the formation of N-2 alkylation product as pointed out by Knorr75
especially with CH3I in
methanol at 100-130 ºC as shown in the reaction below (Scheme 2.19).
29
NN
CH3
O
Ph
+ NN
O
Ph
CH3
CH3
CH3 I + NN
O
Ph
CH3
CH3
CH3CH3100 -130 oC
CH3OH
82435
42
Scheme 2.19; N-2 Cyanoethylation of Pyrazolones with Methyl Iodide.
The product 4 being the major one while 82 is the minor.
2.9.4 Acylation of 1-aryl-2-pyrazoli-5-ones
Acylation reactions of 2-pyrazolin-5-ones are mainly of two types.
I- C-4 Acylation.
II- O-Acylation.
2.9.4a C-4 Acylation.
1-Aryl-3-methyl-2-pyrazolin-5-ones react with various acylating agents to form C-4 acylation
products in good yield. Acylating agents like acid halides153-154
, esters155
and anhydrides156
can
be used easily as was worked initially by many scientists. The reaction with acetyl chloride is
shown below (Scheme 2.20).
NN
CH3
O
Ph
+ CH3 Cl
O
NN O
Ph
CH3
O
CH3
35
83
84
Scheme 2.20; C-4 Acylation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Acetyl chloride.
C-4 acylation reaction of 1-phenyl-3-methyl-2-pyrazolin-5-one with phthalic anhydride is of
special interest. Phthalic anhydride (85) react with two mole of pyrazolone to produce a
substituted methylidene bis (3-methyl-1-phenyl-5-pyrazlone (86)157-158
(Scheme 2.21).
30
NN
CH3
O
Ph
+ O
O
O N
N
N
N PhPh
OO
COOH
CH3 CH3
86
2
3585
Scheme 2.21; C-4 Acylation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Phthalic anhydride.
2.9.4b O-Acylation.
O-acylation of 2-pyrazolin-5-ones can be carried out with benzoyl chloride159
in CHCl3 using
triethylamine as an acid binding agent as given in the reaction below (Scheme 2.22).
NN
O
CH3
Ph
+O
Cl
CHCl3
TriethylamineN
NO
CH3
Ph
O
Ph
88
87
35
Scheme 2.22; O-Acylation of -pyrazolin-5-ones with benzoyl chloride.
Similarly O-acylation products of 1-phenyl-3-methyl-2-pyrazolin-5-one have also been obtained
by Bai et al160
using micro wave irradiation.
2.10 Reactions of 2-pyrazolin-5-ones with amines.
It has been found that 2-pyrazolin-5-ones readily react with several aromatic amines to form
imino derivatives under oxidizing catalytic conditions. The most favorite catalyst for this
reaction is Ag2O. Reaction of N, N-diethyl-3-methyl benzene-1,4-diamine161-162
is presented here
(Scheme 2.23).
31
NN O
CH3
Ph
+
NH2
N
CH3
CH3 CH3
Ag2O
NN
CH3
Ph
O
N N
CH3
CH3CH3
8990
35
Scheme 2.23; Condensation of 1-Aryl-3-methyl-2-pyrazolin-5-ones with primary amines.
2.11 Nitration of 1-aryl-2-pyrazolin-5-ones.
Nitration of 1-aryl-2-pyrazolin-5-ones is of special interest. It has been found to depend on the
nature of nitrating agent, its concentration and temperature as well. Dilute HNO3 on reaction
with1-aryl-2-pyrazolin-5-ones gave 4-nitro product75
.This have also been produced by the
oxidation of 4-oximino derivative163
, shown as under (Scheme 2.24).
NN
O
CH3
Ph
NN
O
CH3
Ph
N+
O-
O
NN
O
CH3
Ph
N OH
O3
91 9235
dil. HNO3
Scheme 2.24; C-4 nitration of 1-Aryl-3-methyl-2-pyrazolin-5-ones.
Similarly nitration of 1-phenyl-3-methyl-2-pyrazolin-5-one with concentrated HNO3 resulted
into the formation of 4,4-dinitro derivative(93).This dinitro derivative may even be further
nitrated on phenyl ring to produce (94) and (95) as was found by Bergman et al.164
presented as
under (Scheme 2.25).
32
NN
O
CH3
NN O
CH3O2N
NO2
Conc.HNO3 Conc.HNO3
NN
O
CH3O2N
NO2
O2N
N
N
O
CH3
O2N
NO2
NO2
NO2Nitrating mixture excess
Nitrating mixture excess
95
9493
35
Scheme 2.25; C-4 Dinitration of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Conc.HNO3.
Recently many nitro and pyrazolone derivatives have synthesized by Ruoqun et al165
by
microwave irradiation.
2.12 Sulphonation of 1-aryl-2-pyrazolin-5–ones.
Sulphonation of 1-aryl-2-pyrazolin-5–ones with H2SO4 gave 4-suphonated product as was
investigated by Kufmann166
. Similarly 1-phenyl-3-methyl-2-pyrazolin-5-one afforded the same
product by the use of 20% oleum at 15-20 ºC as found by Ioffe and Khavin167
(Scheme 2.26).
NN
Ph
O
CH3
NN
Ph
O
CH3 SO3H
9635
H2SO4 or
20% Oleum ,15 -20 oC
Scheme 2.26; C-4 Sulphonation of 1-Aryl-3-methyl-2-pyrazolin-5-ones.
33
2.13 Halogenation of 1-aryl-2-pyrazolin-5–ones.
Almost all pyrazolones especially 1-phenyl-3-methyl-2-pyrazolin-5-one (35), are very easily
halogenated at C-4 position. Thus perching Cl2 gas in a solution of (35) in CHCl3 results in the
formation of 4,4-dichloroderivative (97)75,163
as presented below. The same product is obtained
by the reaction of 1-phenyl-3-methyl-5-pyrazolone with phosphorous pentachloride163,168
(Scheme 2.27)
NN
O
CH3
Ph
NN
O
CH3
Ph
ClCl
NN
O
CH3
Ph
3597
PCl5
35
+Cl2 in Chloroform
Scheme 2.27; C-4 Diclorination of 1-Aryl-3-methyl-2-pyrazolin-5-ones.
Bromination of 35 gave monobromo75
(98) and then dibromo derivatives75,163,168
(99) if excess of
bromine was used. Similarly N-bromobenzamide in THF at room temperature gave only
dibromo62,85
product (99) as indicated below (Scheme 2.28).
NN
O
CH3
Ph
NN
O
CH3
Ph
Br
NN
O
CH3
Ph
BrBr
3598
99
Br2 excess
N-bromobenzamide
Br2 equimolar
THF, room temperature
Scheme 2.28; C-4 Dibromination of 1-Aryl-3-methyl-2-pyrazolin-5-ones with Br2 and NBS.
Iodo derivatives of 1-phenyl-3-methyl-2-pyrazolin-5-one have been obtained by reacting the
pyrazolone with KI in KOH. However the product being unstable were difficult yo get in pure
form169
.
34
2.14 Nitrosation of 1-aryl-2-pyrazolin-5–ones.
1-Aryl-3-methyl-2-pyrazolin-5-ones are very easily nitrosated at C-4 position as have been
studied by many scientists62,163,168
. The nitroso derivatives have been found to exist mainly as an
oxime tautomer (93) shown as under (Scheme 2.29).
NN
O
CH3
Ph
NN
O
CH3
Ph
N OH
NaNO2 +HCl
0 - 5 oC
9335
Scheme 2.29; C-4 nitrosation of 1-Aryl-3-methyl-2-pyrazolin-5-ones.
Metwally et al170
have prepared several nitroso derivatives of 2-pyrazolin5-ones and studied their
condensation reactions with active methylene compounds. These condensation products were
evaluated for their pharmaceutical activities. Bilmar et al171
have also prepared nitroso
derivatives of 1-phenyl-2-pyrazolin-5-ones and studied their tautomerism. Similarly 1-phenyl-2-
pyrazolin-5-ones have also been nitrosated at C-4 by Seo et al172
to get oximo derivative of
biological activity. Recently Samir et al173
have synthesized various 4-nitroso derivatives of 1-
phenyl-2-pyrazolin-5-ones and also studied their Physico-Chemical characteristics.
2.15 Synthesis of Pharmacologically active pyrazole derivatives.
Numerous pyrazole derivatives possess many pharmacological activities. Their synthesis and
study is of special interest. A few modern synthetic approaches of pyrazole derivatives with
pharmacological activities are discussed here.
2.15a Antidepressant Activity.
Several scientists have worked in this field recently. Palaskaa et al174
., have synthesized and
evaluated anti-depressant activity of about ten pyrazole derivatives like compound 100-102
shown as under (Figure 2.3).
35
100
O
H3C NNH
O CH3
O CH3
Cl
NNH
OCH3
OCH3Cl 101
102
H3CO
NNH
OCH3
OCH3
Cl
Figure 2.3; Antidepressant pyrazoles.
Kelekci et al175
., have also worked a lot in this field. Similarly Jayaprakash et al176
., have
synthesized several antidepressant and antituberclosis pyrazole derivatives like 103 (Figure 2.4).
103
NN
OH
OH
OH NH S
Figure 2.4; Antidepressant and antituberclosis pyrazoles.
2.15b Antimicrobial pyrazole derivatives.
Many antimicrobial pyrazole derivatives have been synthesized by different scientists. Ozdemir
et al177
., and Abdelwahab et al178
., have recently synthesized pyrazole antimicrobial compounds
like 104 and 105 respectively (Figure 2.5).
104 105
N
S
R
NN
Ar
S
O
NN N
S
Ar
Ar1
Figure 2.5; Antimicrobial pyrazole derivatives.
36
2.15c Antiamoebic pyrazoles.
Several pyrazole compounds have been found to show antiamoebic properties. Budakoti et al179
synthesized many bromo/chloro pyrazole derivatives of such activity. Compound 106 is a
selected example from their work.
Similarly Abid et al180
., have also worked in this field and synthesized several compounds,out of
these compound 107 had a marked antiamoebic properties (Figure 2.6).
106
Br
Cl
NN
S
N
N
N
Where X= Cl/Br
107
XN
N
S
HN
Figure 2.6; Antiamoebic pyrazole derivatives (106 and107).
2.15d Antioxidant pyrazole derivatives.
Recently Babu et al181
., have worked to produce several pyrazole antioxidants. Compound 108
and 109 have been selected as examples from their work (Figure 2.7).
108
NN
SO2NH2
F3C
NH
109
CH3
N N
O
O
O O
OH
Figure 2.7; Antioxidant pyrazole derivatives.
37
2.15e Cholesterol inhibiting pyrazoles.
Jeong et al182
., have prepared pyrazole compounds having Cholesterol inhibiting characteristics.
Compound 110 is an example from this work (Figure 2.8).
110
OCH3
N
N
S
NH OCH3
OH
Figure 2.8; Cholesterol inhibiting pyrazole derivative
2.15f Insecticidal pyrazole compouds.
Several pyrazole derivatives with insecticidal properties have been synthesized by Silver et al183
.
The mechanism of this activity was also studied by these scientists. Compound 111 has been
selected as an example from this work (Figure 2.9).
111
Cl
Cl
NN
NH O
Figure 2.9; Insecticidal pyrazole derivative
2.15g Antibacterial pyrazoles.
A large number of antibacterial pyrazole derivatives have been synthesized by different
scientists. The work of Chimneti et al184
and Vijavergiya et al185
in this field is of special
interest. Compounds 112 and 113 are the examples of their respective work (Figure 2.10).
38
NN
CH3O
OCH3
NN
CH3O
CH3
ClClH3CO
112 113
Figure 2.10; Antibacterial pyrazole derivative.
2.15h Antitubercular pyrazole derivatives.
Pyrazoles with antitubercular activity have been synthesized by many scientists. The work of
Kini et al186
and Ali et al187
is of special appreciation. Compound 114 and 115 are selected
examples from their respective work (Figure 2.11).
N NN
O
O
114 115
CH3
H3CO
Cl
Cl
NH
NN
S
Figure 2.11; Antitubercular pyrazole derivative.
2.15i Anticancer pyrazole compounds.
Several pyrazole derivatives with anticancer properties have been synthesized by many
scientists. Havrylyuk et al188
., have made a very good attempt in this field. Compound 116 is an
example selected from their work. Similar synthetic work has been done by Bhat et al189
.Compound 117 has been shown as an example from this work (Figure 2.12).
116
HO
H3CO
H3CO
NN
HO
NS
O 117
H3CO
OCH3
H3CO
H3CO
N NH
F
`
Figure 2.12; Anticancer pyrazole derivative
39
2.15j Amine Oxidase Inhibiting pyrazoles.
A large number of pyrazole derivatives have Amine Oxidase inhibition properties. Manna et al190
have synthesized several such compounds. Compound 118 is an example from their valuable
work (Figure 2.13).
118
OH
OH
N N
O
CH3
CH3
Figure 2.13; Amine oxidase inhibitor pyrazole derivative.
2.15k Antihypertensive pyrazole derivatives.
Manny pyrazole derivatives have been found to be antihypertensive. Compound 119 is one of the
several compounds of this category synthesized by Turan-Zatouni et al191
(Figure 2.14).
119
H3CO
OH
NN
NS
OCH3
Figure 2.14; Antihypertensive pyrazole derivative.
2.15l Oxidation of pyrazoles.
Pyrazole are very sensitive to Oxidation depending on the nature of oxidizing agent. Mild
oxidizing agents like Nitrous acid62
, phenylhydrazine192-193
and even ferric chloride194
in small
amounts convert 3-methyl-1-phenyl-2-pyrazolin-5-one to a 4,4'-bipyrazole derivative (120)
shown as under (Scheme 2.30).
40
N
N
CH3
O
N
N
CH3
OH
N
N
CH3
OHNitrous acid
Ferric Chloride
Phenylhydrazine
2
12035
Scheme 2.30; Oxidative coupling of 3-methyl-1-phenyl-2-pyrazolin-5-one.
However strong oxidizing agents like KMnO4 completely destroy the whole ring system forming
water, nitrogen, CO2 and pyruvic acid194-195
etc.
2.16 Synthesis of 1-aryl-2-pyrazolin-5-one dyes.
Perhaps the most important and wide use of the pyrazolones especially 2-pyrazolin-5-ones, is
their use as couplers for dyes synthesis. The synthetic history of pyrzole dyes is as old as the
discovery of pyrazole itself. Tartarzine was the Ist dye to be synthesized by Zeigler and
Locher174a
in 1884. The coupling takes place at C-4 in 2-pyrazolin-5-ones producing a monoazo
dye as indicated below for the synthesis of Tartrazine (Scheme 2.31).
Tartrazine
Na+
Na+
Na+ -OOC
NN
O
SO3
-
+
SO3
-
N+
N
0 - 5 oC
Na2CO3
Na+
121
122
Na+ -OOC
NN OH
SO3
-
N N
SO3
-
Scheme 2.31; Synthesis of pyrazolone derivative dye, Tartrazine.
41
Liu and Jia196
have prepared many Transition metal complexes of 1-phenyl-3-methyl-4-benzoyl
pyrazole-5-ones after forming the semicarbazones of pyrazole shown as below for dye (123)
(Figure 2.15).
Where M+ is a transition metal with i t's positive charge.
123
NN
CH3
O
N
N
NH2
O
NN
CH3
O
N
N
NH2
O
M+
Ph
Ph
Figure 2.15; Metal complexes of 1-phenyl-3-methyl-4-benzoyl pyrazole-5-ones.
Shindy et al197
., have prepared several pyrazole based cyanine dyes and have also done the
spectral studies of their dyes. Dye (124) as shown below is a selected example of this research
work (Figure 2.16).
I-
I-
124
N+
CH3
O
NH
NH
O
N
N
N
N
O
O
CH3
CH3
N+
CH3
Figure 2.16; Pyrazole cyanine dye.
Similarly Rizk et al198
have synthesized many new dyes of pyrazole origin. These scientists also
studied the fastness properties of their dyes after application on wool, polyester and blends of
polyester. Most of their dyes were of disperse type. Dyes 125 and 126 are selected examples
from this work (Figure 2.17).
42
N N
NN
NH2
COOHN N
NN
NH2
OCH3
Cl
125 126
Figure 2.17; Pyrazole based Disperse Dyes.
In the same way Mohamed et al199
., have synthesized three new series of pyrazole based
bifuncntioal reactive dyes. Several properties of these dyes like color strength, light fastness,
Molar Extinction Coefficient and washing fastness etc. were studied after the application of these
dyes on cotton and wool.
Abdou et al200
., have also synthesized many new disazo disperse dyes based on
3(2-hydroxyphenyl) 2-pyrazolin-5-ones. These disperse dyes were applied to polyester. The
fastness properties of the dyes were evaluated along with the position of color in CIE LAB
coordinates. The possible tautomeric structures were also screened using proton NMR and FTIR
spectroscopy. Dye 127 is an example selected from this work (Figure 2.18).
127
N+
O-
O
OH
N N
NN
OHNN
Figure 2.18; Disazo disperse dyes based on 3(2-hydroxyphenyl) 2-pyrazolin-5-ones.
43
Metwally et al201
have also synthesized novel 4-arylhydrazono-3(2-hydroxyphenyl) 2-pyrazolin-
5-ones and applied these as disperse dyes for dying polyester. The fastness properties of these
dyes were also studied in detail. Dye 128 is a representative example of this work (Figure 2.19).
128
OH
NN O
N N
H
Figure 2.19; 4-arylhydrazono-3(2-hydroxyphenyl) 2-pyrazolin-5-ones based disperse dyes.
Recently Şener and Şarkaya202
have synthesized 2-pyrazoline based tetrakisazo Calix-[4]
resorcinarene dyes. The dyes were evaluated for their tautomerism by proton NMR& FT-IR.
Moreover the chromophoric shifts depending on pH were also determined. Dye 129 has been
selected as a representative example of this work (Figure 2.20).
129
N N
NNH
CH3
NN
NH
NCH3
NN
NH
N
N N
CH3
OH
OH
OH
OH
N N
CH3
N NCH3
CH3
CH3
OH
OH
OH
OH
N N
NH
N
N N
CH3
Figure 2.20; Pyrazoline based tetrakisazo Calix-[4] resorcinarene dyes.
Similarly Otutu203
has also synthesized pyrazole and thiadiazole based dyes for polyester. The
dyes were evaluated by spectroscopic techniques like 1HNMR,
13CNMR and FTIR. These dyes
showed very good fastness properties. Moreover these dyes were also found to be good
photoconductors as well. Dye 130 and 131 are the selected examples from this work (Figure
2.21).
44
N N
NNH
NH2
NN
S
SH
N N
NNH
NH2
CH3N
N
S
SH
130 131
Figure 2.21; pyrazole and thiadiazole based heterocyclic dyes.
Jiang et al204
have prepared ten Copper complexes of pyrazole derivatives and elucidated their
structures by FTIR, 1HNMR and MS spectroscopic techniques. These complexes were found to
be active catalysts in the degradation of Methyl Orange and Methylene Blue. Complex 132 is a
selected example from this work (Figure 2.22).
OH2
Cl
N NN+
O-
O
S
NHCu
132
Figure 2.22; Copper complexes of pyrazole derivatives.
Similarly Abdelgawad et al205
., have prepared numerous pyrazole dyes of amino sites and linked
these with benzimidazole, benzoxazole and benzothiazole . These derivatives were tested for
anticancer activities. Compound 133 is a selected example from this research work (Figure
2.23).
133
N
N
NH2
NH2
N N
NH
NH
Figure 2.23.; Pyrazole based dye with anticancer activity.
45
Recently Elmaaty et al206
have also synthesized pyrazole disperse dyes and applied these to
ultrasound treated PET fabric. The color strength was measured in Absorbance and CIELAB
coordinates. Dye properties like washing, rubbing and light fastness were evaluated. Moreover
Antibacterial properties of these dyes were also determined. Dye 134 and 135 are two selected
examples (Figure 2.24).
N
N
NH2
NH2
N
N N+
O-
O
N
N
NH2
NH2
N
N Cl
134135
Figure 2.24; Pyrazoles based disperse dyes.
In the same way Şener and Aydin207
have synthesized nine novel tetrakisazo dyes of pyrazole
origin. The dyes were characterized by FTIR, 1HNMR and MS techniques. The synthetic scheme
consisted of tetrazotization of Benzedine, coupling with 5-amino-pyrazoles, then diazotizing the
amine and re-coupling with new couplers. Dye 136 is a representative example of this research
scheme (Figure 2.25).
OH
NNH
NN
N
N
N
NNH
N
NN
HO
CH3H3C
136
Figure 2.25; Pyrazoles based Tetrakisazo dyes.
2.17 Synthesis of 1-aryl-2-pyrazolin-5-one Pigments.
Several pyrazole pigments have been synthesized by many research scientists. Among these
pigments the most favorite and widely used are Pigment Orange13 (137)208
Pigment Orange 34
(138)208
and Pigment Red 38(139)209
(Figure 2.26).
46
NN
NN N N
NN
OH HO
H3C CH3
ClCl
137
NN
NN N N
NN
OH HO
H3C CH3
ClCl
CH3 CH3
138
139
NN
NN N N
NN
OH HO
C2H5OOC COOC2H5
ClCl
Figure 2.26; Pyrazoles based Pigments Orange13 (137), Orange 34 (138) and Red 38(139).
2.18 Condensed pyrazoles with other heterocyclics and their dyes.
This is another vast field of research. Pyrazole have been condensed with several other
heterocyclics like pyrazole itself, pyridine, pyrimidines and pyranes etc. Several condensation
schemes are possible with the same heterocyclic including 1,2-a, 1,2-b, 1,2-c, 1,2-d, 2,3-a 2, 3-b,
2,3-c, 2,3-d etc. Syntheses of a few condensed systems are presented here.
2.18a Pyranopyrazoles and their dyes.
There are several types of pyranopyrazole condensation products. Khan and Cosenza210
have
synthesized and evaluated the reactivity of several pyranopyrazoles. Moreover the structures of
the synthesized compounds were elucidated using IR and NMR spectroscopy. Recently Al-
Amiery et al211
have synthesized series of novel pyranopyrazoles and their dyes as well. These
have been characterized by UV-VIS., FT-IR, 1HNMR and
13CNMR.Moreover theoretical studies
based on ―Density Function Theory‖ were also carried out by these scientists. Dye 140 is
presented as an example from this work (Figure 2.27).
N N
N
NH
CH3
O O
CH3 O
OC2H5
140
Figure 2.27; Pyranopyrazoles based dyes.
47
2.18b Pyrazolopyrimidines and their dyes.
Pyrazolopyrimidines are also of a large variety regarding the condensation schemes. Recently
Youssef et al212
have synthesized disazo pyrazolo[1,5-a] pyrimidine reactive dyes. The dyes were
applied on cotton, wool and silk and evaluated for the dyeing properties. Most of these dyes had
very good light fastness, washing fastness rubbing fastness and perspiration fastness. Dye 141 is
a selected example from this work (Figure 2.28).
141N
N
N
OH OH
NNN N
HO3S
S
O
O
O
SO
OOH
CH3
Figure 2.28; Disazo pyrazolo [1,5-a] pyrimidine reactive dyes.
Similarly Kamel et al213
., have also synthesized bifunctional pyrazolo[1,5-a]pyrimidine reactive
dyes. These dyes were applied to cotton, wool and silk. The fastness properties like light
fastness, washing fastness, rubbing fastness and perspiration fastness were found to be very
good. Dyes 142 and 143 are two selected examples from this work (Figure 2.29).
142N
N
N
OH OH
NNN N S
O
O
O
SO3
- Na
+
NH2
H
Na+ -O3S
.
2
143
2
Na+ -O3S
.
H
NN
Na+ -O3S
N
N
N
OH OH
N N
NH2
NH
N
N
N
Cl
Na+ -O3S NH
Figure 2.29; Bifunctional pyrazolo [1, 5-a] pyrimidine reactive dyes.
48
Chapter 3 EXPERIMENTAL
The present thesis deals with pyrazole derivatives and dyes: synthesis and their applications.
Hence for this purpose various pyrazole dyes were prepared. The main reactions were conducted
by the use of different raw materials like pyrazolones, phenols, naphthols, resorcinol,
aminonaphthols, naphthol-sulphonic acids and bis-phenols etc. Almost all of the chemicals used
were of laboratory grade and used as such. However a few of these were purified by the common
methods given in the literature. The equipment and instruments used were as under.
3.1 Equipment used:
Various types of equipments used were:
i - Melting Point apparatus, Gallenkamp, UK.
ii - Oven, Model # UN75, Memmert, GmbH, Germany.
iii - Multiple Mixer (Falcon Faisalabad Pak.)
iv - Leather Dying Drum Machine = Jiangsu Lianyungang Leather Machinery Factory China,
Model # R-350-6
v- Light Fastness by Xenon Fad-o-meter Model# XF-15N,Shimudzu Corporation Kyoto Japan.
vi- pH Meter = Model = Eutech pH 5+, Eutech Instruments ,USA.
3.2 Instruments used:
i - FTIR, Agilent Cary 630, Agilent Technologies USA.
ii - NMR Bruker DPX 400-Operating at 300/75-13
C M Hz.
iii - Single Crystal X-Ray Machine = Bruker AXS Smart APEX II Single Crystal Diffractometer,
Bruker, USA.
iv - UV-Visible Spectrophotometer = Spectra Flash SF 550,Datacolor Inc.,USA.
49
v - CHN-analyzer = Flash EA 1112 elemental analyzer, Thermo-Fisher Inc. Walthman,
Massachusetts, USA.
3.3 SYNTHESIS OF DIAZONIUM COMPOUND OF SPMP.
This research work consisted of steps like nitrosation of SPMP [1(4-sulphophenyl) 3-methyl-2-
pyrazolin-5-one], reduction of nitroso derivative, diazotization and isolation of diazonium
compound.
3.3.1 Nitrosation of SPMP
In this step SPMP was nitrosated at 0-5ºC using NaNO2 and HCl as described by Knorr1.For this
purpose 25.4g(0.1mole)SPMP was dissolved in 250mL water containing 5.0g(0.125mole)
NaOH. Then 50mL HCl (32%) was added to precipitate SPMP as a very fine paste. The beaker
was jacketed and 100g ice was also added in the paste. A solution of 7.2g (0.104mole) Sodium
nitrite was added drop wise in a period of one hour .The nitrosation was conducted for further
one hour at 0-5ºC.The nitrosated product was a clear solution. The nitroso compound was
filtered to remove some terry material. The clarified nitroso derivative was isolated by salting out
at 15% salt concentration .The nitrosated product yield was 26.0g = 92.1%.
3.3.2 Reduction of Nitroso derivative to amine
In this process reduction of nitroso derivative of SPMP was carried at 100-105ºC using Zinc and
HCl. A mixture of 400mL water and HCl (3:1) was heated to boiling. Then 32.6g (0.1molee
nitroso containing 15% salt) nitroso derivative of SPMP and 30g zinc metal were added
alternatively in small portions at boil. The reduction was completed as the solution became
colorless. A small amount of additional zinc was added and the resultant Amine hydrochloride
was quenched to -7ºC. The excess un-reacted zinc was removed by filtration. The amine being
unstable, cannot be isolated, hence next step diazotization was carried out.
3.3.3 Diazotization
In this step, the amine hydrochloride of SPMP was diazotized using an aqueous solution of
NaNO2 (6.9g dissolved in 250mL of solution) at -5 to -2ºC.The diazotization was completed in
about 3.30hours. It was almost a clear solution with some flocculants which were removed by
50
filtration. The diazonium compound was isolated by the addition of common salt @28% and
keeping the same for 18-20h at 0-5ºC. Filteration afforded yellow diazonium compound. This
was crystallized from rectified sprit to get yellow needles of diazonium compound which was
dried to give the desired product.
Yield: 29.5g (87%)
3.4 General Scheme-1 for the Synthesis of Naphthol-AS Series of Dyes
Dyes = 3a-g
N
N
CH3
O
N
N
O
NHO R1
R2
R3R4
HO3S
N
N
CH3
O
N
N
O
NH OR1
R2
R3 R4
SO3HCr
-
OH2OH2
OH2
N
N
CH3
O
N
N
O
NHO R1
R2
R3R4
M
HO3S
65 -75 oC
Cr(CH3COO-)3
100 - 105 oC
2a R1 =R2= R3 =R4=H
2c R2= R3 =R4=H,R4=CH32b R1 = R3 =R4=H,R2=NO22d R1= R2 =R4=H,R3=Cl
2e R1= R4 = OCH3,R2=H,R3=Cl 2f R1= OCH3,R2=R3,R4=H 2g R1= OC2H5,R2=R3,R4=H
3a-g Dyes = 201,205,209,213,217,221,225
5a-g Dyes = 203,207,211,215,219,223,227
6a-g Dyes = 204,208,212,216,220,224,228
7a-g Dyes = 202,206,210,214,218,222,2267a-g Dyes
5a-g,6a-g Dyes
Metal Salts 4a-b
4a= FeSO4 .7H2O
4b= CuSO4 .5H2O
N
N
CH3
OH
HO3S
N
N
O
NHOH R1
R2
R3R4
3.4.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP)
1-(p-sulphophenyl)-3-methyl-5-pyrazolone (144) (25.4 g, 0.1 mol) was suspended in H2O (250
mL). Hydrochloric acid (45 mL) was added to this well stirred suspension. The reaction mixture
was cooled to 0-5°C in an ice bath. A solution of NaNO2 (6.9 g, 0.1 mol) in H2O (25 mL)
previously cooled to 0°C, was then added over a period of 35 minutes with stirring. The stirring
was continued for an hour maintaining the same temperature, with a positive test for nitrous acid.
Later on the excess of nitrous acid was destroyed with required amount of sulphamic acid. The
Nitroso (Oxime) was filtered after salting out. The nitroso was reduced by stirring in 200mL
water containing 85mL HCl and 23g Zinc metal(added in small portions) at boil for 4 hours to
complete the reduction (reaction contents became colorless).
51
3.4.2 Diazotization and Coupling with Naphthol AS Couplers
To the well stirred ice jacketed aqueous suspention (2.69 g) of 1( p-sulphophenyl)-3-methyl-4-
amino pyrazolone at 0-5 oC was added sodium nitrite solution (0.7 g) and to it 3.5 mL conc. HCl
was added. The reaction mixture was vigorously stirred for 3h at the above low temperature to
achieve the diazonium salt of 1-(p-sulphophenyl)-3-methyl-4-amino pyrazolone. After the
synthesis of diazonium compound, it was coupled with 0.010 mol (2.780 g) coupler Naphthol-
ASA (2a) dissolved in 200 mL water containing 0.45 g NaOH. The coupling was facilitated
using sodium carbonate as acid binding agent. The reaction mixture was given 4.50 h to
complete the coupling at 0-5 oC. The dye was brought to room temperature; pH was reduced
upto 4.5 by HCl, filtered and dried in oven at 70-75 oC till constant weight was obtained with
percentage yield of 85%. By adopting the same procedure other dyes 3b-g were prepared from
couplers 2b-g (General Scheme-1).
3.4.3 Metallization of Acid Dyes
For the synthesis of metal complexes (Iron complex), pH of 25mL of dye 3a (0.005M) was
reduced to 6.5 with HCl. Then it was heated to 70oC and to it 5 mL (0.005mol Fe
+2) solution of
ferrous sulfate (FeSO4.7H2O) was added drop wise. Mixing and heating at this temperature was
continued for further 1.0 hours till the metallization was completed as shown by the comparative
TLC. The dye was cooled to room temperature; its pH was reduced to 1.0 with conc. HCl. The
dye was salted out with sodium chloride, which was subsequently filtered and dried in oven at
80oC till constant weight.
Similarly Chromium (III) and Copper (II) complexes of dye 3a were prepared by treating dye
with Cr (CH3COO-)3 and CuSO4.5H2O at 100-105
oC and 65-70
oC for chromium and copper
respectively. In this way complexes 5a-g, 6a-g and 7a-g were synthesized from respective dye
ligands.
201 (C27H21N5O6S)
Orange, (76.11%) λmax in nm (log ε): 614 (3.54), 396 (3.82), 355 (3.54). FTIR (KBr, cm-1
) νmax:
3298 (NH, str), 3050 (C=C-H), 2924(CH2)1675 (C=O), 1619, 1559 (C=C aromatic), DMSO-
d61448 (N=N, str), 1343(CH2), 1209 (S=O, str), 1174(C-O), 872 (Ar-H). 1H NMR (300 MHz,) δ:
12.03 (1H, s, O-H), 9.98 (1H, s, N-H), 8.36 (1H, d), 8.14 (2H, d), 7.89 (1H, s), 7.84 (1H, s,
52
SO3H), 7.77 (2H, d), 7.75 (1H, d), 7.61 (1H, t), 7.40 (2H, d), 7.32 (2H, t), 7.29 (1H, t), 7.08(1H,
t), 4.81 (1H,s), 2.47(3H, s).13
C NMR (75 MHz, DMSO-d6) δ: 167.91, 165.19, 160.80, 159.86,
140.53, 137.94, 136.68, 135.45, 131.75, 130.73, 129.03, 129.03, 128.86, 128.49, 128.21, 126.58,
126.58, 126.33, 124.91, 123.89, 122.49, 122.49, 120.14, 118.16, 70.40, 13.12. Anal. Calcd. For
C27H21N5O6S: C, 59.66; H, 3.89; N, 12.88; S, 5.90; Found: 59.66; H, 3.89; N, 12.88; S, 5.90.
205 (C27H20N6O8S)
Brown, (75.65%) λmax in nm (log ε): 608 (3.67), 396 (3.49), 355 (3.48). FTIR (KBr, cm-1
) νmax:
3293 (NH, str), 3065 (C=C-H), 2924 (C-H, str), 1670 (C=O), 1620, 1526 (C=C aromatic), 1445
(N=N, str), 1317(CH2), 1209 (S=O, str), 1050 (C-O), 875 (Ar-H). 1HNMR (300 MHz, DMSO-
d6) δ: 10.03 (1H, s, N-H), 8.56 (1H, s), 8.33 (1H, s), 8.19 (1H, d), 8.16 (2H, d), 8.02 (1H, d), 7.87
(1H, s, SO3H), 7.83 (2H, d), 7.78 -7.59 (3H, m), 7.41-7.24 (2H, m), 6.35(1H, s, O-H), 4.84 (1H,
s), 2.44 (3H, s).13
C-NMR (75 MHz DMSO-d6) δ (ppm) : 167.91, 165.19, 160.80, 159.86, 148.41,
140.53, 138.96, 137.94, 135.45, 131.75, 130.73, 128.67, 128.49, 128.21, 127.81, 126.58, 126.33,
123.89, 120.85, 120.14, 118.16, 116.67, 68.95, 13.12. Anal. Calcd. For C27H20N6O8S: C, 55.10;
H, 3.43; N, 14.28; S, 5.45, Found: C, 55.10; H, 3.43; N, 14.28; S, 5.45.
209 (C28H23N5O6S)
Tan, (81.15%) λmax in nm (log ε): 643 (3.65), 396 (3.60), 355 (3.44). FTIR (KBr, cm-1
) νmax:
3315 (NH, str), 3049 (C=C-H), 2920 (CH2), 1675 (C=O), 1623, 1545 (C=C aromatic), 1459
(N=N), 1343(C-H, bend), 1159 (S=O), 883 (Ar-H). 1H-NMR (300 MHz, DMSO-d6) δ: 9.78
(1H, s, N-H), 8.32 (1H, s), 8.17 (2H, d), 7.83 (2H, d), 7.81 (1H, s, SO3H), 7.80 (1H, d), 7.54 (1H,
d), 7.52-7.38 (2H, m), 7.27-7.03 (4H, m), 4.89 (1H, s), 2.41 (3H, s), 2.32 (3H, s). 13
C-NMR (75
MHz, DMSO-d6) δ (ppm): 166.74, 165.19, 160.80, 159.86, 140.53, 137.94, 136.28, 135.45,
131.75, 131.42, 130.73, 129.83, 128.86, 128.49, 128.21, 127.66, 126.58, 126.33, 126.22, 123.89,
123.36, 120.14, 118.16, 118.16, 69.90, 17.35, 13.12. Anal. Calcd. For C28H23N5O6S: C, 60.32;
H, 4.16; N, 12.56; S, 5.75; Found: C, 60.32; H, 4.16; N, 12.56; S, 5.75.
213 (C27H20ClN5O6S)
Tan, (80.72%).λmax (nm) (log ε): 635 (3.72), 455 (3.61), 396 (3.60), 355 (3.52). FTIR (KBr, cm-
1) νmax: 3448 (OH, NH), 3054 (C-H, str), 2920 (C-H. aliphatic), 1680 (C=O, str), 1660, 1597,
1539 (C=C aromatic), 1489 (N=N, str), 1325(C-H, bend), 1159 (S=O str), 1070, C-O), 827
(C=C, bend). 1HNMR (300 MHz, DMSO-d6) δ: 10.16 (1H, s, N-H), 8.31(1H,s), 8.17(2H, d),
7.95 (1H, s, SO3H), 7.83(1H, d), 7.52- 7.38(2H, m), 7.41(2H, d), 7.35 (2H, d), 7.27(1H, t), 4.89
53
(1H, s), 2.41(3H, s). 13
CNMR (75 MHz, DMSO-d6) δ (ppm) : 167.91, 165.19, 160.80, 159.86,
140.53, 137.94, 136.21, 135.45, 131.75, 130.73, 129.97, 128.99, 128.86, 128.49, 128.21, 126.58,
126.33, 123.89, 123.04, 120.14, 118.16, 70.54, 13.12. Anal. Calcd. For C27H20ClN5O6S: C,
56.11; H, 3.49; N, 12.12; O, 16.61; S, 5.55; Found: C, 56.11; H, 3.49; N, 12.12; S, 5.55.
217 (C28H23N5O7S)
Orange, (80.72%). λmax in nm (log ε): 635 (3.72), 455 (3.61), 396 (3.60), 355 (3.52). FTIR (KBr,
cm-1
) νmax: 3305 (NH, s), 3054 (C-H, str), 2925 (C-H. aliphatic), 1673 (C=O, str), 1635, 1560
(C=C aromatic), 1453 (N=N, str), 1320 (C-H, bend), 1240 (S=O str), 1056, C-O), 880 (C=C,
bend). 1HNMR (300 MHz, DMSO-d6) δ: 12.65 (1H, s, O-H), 10.32 (1H, s, N-H), 8.15 (2H, d),
7.85 (2H, d), 7.80 (1H, s, SO3H), 7.73(1H, s), 7.83-7.75 (2H, m), 7.71 (1H, d), 7.65 (1H, d),
7.05- 6.72 (4H, m), 4.81(1H, s), 3.82 (3H, s), 2.34 (3H, s). 13
C-NMR (75 MHz, DMSO-d6) δ
(ppm) : 166.74, 165.19, 160.80, 159.86, 149.93, 140.53, 137.94, 135.45, 131.75, 130.73, 128.86,
128.49, 128.26, 128.21, 126.58, 126.33, 126.07, 123.89, 122.81, 121.32, 120.14, 118.16, 112.38,
69.52, 56.79, 13.12. Anal. Calcd. For C28H23N5O7S: C, 58.63; H, 4.04; N, 12.21; S, 5.59; Found:
C, 58.63; H, 4.04; N, 12.21; S, 5.59.
225 (C29H24Cl N5O8S)
Bordeaux, (83.22%). λmax in nm (log ε): 609 (3.49), 455 (3.72), 396 (3.67), 355 (3.47). FTIR
(KBr, cm-1
) νmax: 3311 (NH, s), 3050 (C-H, str), 2924 (C-H. aliphatic), 1685 (C=O, str), 1654,
1541 (C=C aromatic), 1451 (N=N, str), 1332(C-H, bend), 1260 (S=O str), 1030, C-O), 850
(C=C, bend). 1H-NMR (300 MHz, DMSO) δ: 9.14 (1H, s, N-H), 8.34 (1H, d), 8.30 (1H, s), 8.15
(2H,d), 7.96 (1H, s, SO3H), 7.82 (2H,d), 7.80-7.70 (m, 2H), 6.75 (2H, s), 6.45(1H, s, O-H),
4.26(1H, s), 3.82(6H, s), 2.43(3H, s).13
C-NMR (75 MHz, DMSO-d6) δ (ppm) : 165.65, 165.19,
160.80, 159.86, 154.30, 154.30, 140.53, 137.94, 135.45, 131.88, 131.75, 130.73, 128.86, 128.49,
128.21, 126.58, 126.33, 126.07, 123.89, 120.14, 118.16, 105.57, 68.78, 56.79, 56.79, 13.12.
Anal. Calcd. For C29H24Cl N5O8S: C, 54.59; H, 3.79; N, 10.98; O, S, 5.02; Found: C, 54.59; H,
3.79; N, 10.98; S, 5.02.
203 C27H25FeN5O9S
Brown, λmax in nm (log ε): 480, 3274.5 (NH, str), 3021(C=C-H), 2922(CH2), 2851, 1593, 1541,
1489 (C=C aromatic), 1438 (N=N), 1382 (C-H, bend), 1309 (S=O), 1151 (C-O), 915(C=C-H,
bend), 590 (Fe-N, str). Anal. Calcd. For C27H25FeN5O9S; C, 49.78; H, 3.87; N, 10.75; S, 4.92.
Found: C, 49.67; H, 3.93; N, 10.70; S, 4.98
54
207 C27H24FeN6O11S
Dark Brown, λmax in nm (log ε): 475, 3274(NH, str), 3021(C=C-H), 2922(CH2), 2851, 1593,
1541, 1489 (C=C aromatic), 1436(N=N), 1382 (C-H, bend), 1151 (C-O), 827 (C=C-H, bend),
743(C=C-H, bend), 585 (Fe-N, str). Anal. Calcd. For C27H24FeN6O11S; C, 46.57; H, 3.47; Fe,
8.02; N, 12.07; S, 4.60. Found: C, 46.51; H, 3.50; N, 12.00; S, 4.68.
211 C27H24ClFeN5O9S
Dark Brown, λmax in nm (log ε): 493, 3289 (NH, str), 3050(C=C-H), 1689 (C=O), 1559(C=C
aromatic), 1448(N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 887, 870, 708 (C=C-H, bend), 589
(Fe-N, str). Anal. Calcd. For C27H24ClFeN5O9S; C, 47.28; H, 3.53; Fe, 8.14; N, 10.21; S, 4.67. ;
Found: C, 47.36; H, 3.59; Fe, 8.10; N, 10.16; S, 4.70.
215 C28H27FeN5O9S
Brown, λmax in nm (log ε): 480, 3296(NH, str), 3050(C=C-H), 1593, 1559(C=C aromatic),
1448(N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 870, 708, 687 (C=C-H, bend), 578 (Fe-N,
str). Anal. Calcd. For C28H27FeN5O9S; C, 50.54; H, 4.09; N, 10.52; S, 4.82; Found: C, 50.50; H,
4.19; Fe, 8.30; N, 10.43; S, 4.86.
219 C29H29FeN5O10S
Brown, λmax in nm (log ε): 479, 3296 (N-H, str), 3052(C=C-H), 1619, 1559 (C=C aromatic),
1448 (N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 870,739,708,687(C=C-H, bend), 583 (Fe-N,
str). Anal. Calcd. For C29H29FeN5O10S ; C, 50.08; H, 4.20; N, 10.07; S, 4.61; Found: C, 50.00;
H, 4.28; N, 10.00; S, 4.67
227 C29H28 ClFeN5O11S
Grey, λmax in nm (log ε): 482, 3276 (NH, str), 3170 (C=C-H), 3054 (C=C-H), 2950 (CH2), 2853
(C-H), 1595, 1541(C=C, Aromatic), 1489(N=N), 1330 (C-H, bend), 1157(C-O), 827 (C=C-H,
bend), 586 (Fe-N, str). Anal. Calcd. For C29H28 ClFeN5O11S; C, 46.70; H, 3.78; N, 9.39; S, 4.30;
Found: C, 46.61; H, 3.84; N, 9.30; S, 4.37.
204 C27H25CuN5O9S
Tan, λmax in nm (log ε): 509, 3315 (NH, str), 3127(C=C-H), 1623, 1587, 1541(C=C, Aromatic),
1459 (N=N), 1343 (C-H), 1200 (S=O),1174 (C-O), 884(C=C-H, bend), 530 (Cu-N). Anal. Calcd.
For C27H25CuN5O9S; C, 49.20; H, 3.82; N, 10.63; S, 4.86; Found: C, 49.11; H, 3.86; N, 10.54;
S, 4.89.
55
208 C27H24CuN6O11S
Violet, λmax in nm (log ε): 525, 3315(NH, str), 3123(C=C-H), 1541, 1489 (C=C, Aromatic),
1457(N=N), 1340 (C-H, bend), 1202 (S=O),1159 (C-O), 918,827,741 (C=C-H, bend), 536 (Cu-
N). Anal. Calcd. For C27H24CuN6O11S; C, 46.06; H, 3.44; N, 11.94; S, 4.55; Found: C, 45.90;
H, 3.50; N, 11.81; S, 4.65.
212 C27H24ClCuN5O9S
Violet, λmax in nm (log ε): 524, 3313(NH, str), 3052(C=C-H), 2927 (C-H, str), 1654, 1555, 1541
(C=C, Aromatic), 1449 (N=N), 1332(C-H, bend), 1118(C-O), 997,834,732 (C=C-H, bend), 529
(Cu-N). Anal. Calcd. For C27H24ClCuN5O9S; C, 46.76; H, 3.49; N, 10.10; S, 4.62; Found: C,
46.65; H, 3.54; N, 10.01; S, 4.68.
216 C28H27CuN5O9S
Dark Brown, λmax in nm (log ε): 525, 3380 (NH, str), 2924(C-H, str), 1597, 1526(C=C), 1425
(N=N), 1340(C-H, bend), 1157(C-O), 1120(C-O), 834,788,741(C=C-H, bend), 526 (Cu-N).
Anal. Calcd. For C28H27CuN5O9S; C, 49.96; H, 4.04; N, 10.40; S, 4.76; Found: C, 49.88; H,
4.09; N, 10.32; S, 4.85.
220 C29H29CuN5O10S
Tan, λmax in nm (log ε): 510, 3423 (OH, str), 3315 (N-H), 3054 (C=C-H), 2981 (C-H), 1533,
1490 (C=C, Aromatic), 1431(N=N), 1338 (C-H, bend),1157 (C-O) , 833, 788, 730 (C=C-H,
bend), 533 (Cu-N). Anal. Calcd. For C29H29CuN5O10S; C, 49.53; H, 4.16; N, 9.96; S, 4.56.
Found: C, 49.47; H, 4.22; N, 9.81; S, 4.61.
228 C29H28 ClCuN5O11S
Dark Brown, λmax in nm (log ε): 509, 3319 (N-H), 3087(C=C-H), 1597, 1522 (C=C, Aromatic),
1429 (N=N), 1340 (C-H, bend), 1157(C-O), 889,734 (C=C-H, bend), 525 (Cu-N). Anal. Calcd.
For C, 46.22; H, 3.75; N, 9.29; S, 4.25; Found: C, 46.10; H, 3.78; N, 9.20; S, 4.30.
202 C54H38CrN10O12S2
Pink, λmax in nm (log ε): 511, 3311(N-H), 3088 (C=C-H), 1595, 1524 (C=C, Aromatic), 1423
(N=N), 1317 (C-H, bend), 1209 (S=O), 1148 (C-O), 998, 732 (C=C-H, bend), 618 (Cr-N). Anal.
Calcd. For C54H38CrN10O12S2; C, 57.14; H, 3.37; N, 12.34; S, 5.65; Found: C, 57.10; H, 3.40;
N, 12.26; S, 5.71.
56
206 C54H36CrN12O16S2
Violet Brown, λmax in nm (log ε): 522, 3305 (N-H), 3084(C=C-H), 2955 (C-H), 1599, 1522
(C=C, Aromatic), 1429 (N=N), 1340 (C-H, bend), 1123(C-O), 831,734 (C=C-H, bend), 629 (Cr-
N). Anal. Calcd. For C54H36CrN12O16S2; C, 52.94; H, 2.96; N, 13.72; O, 20.90; S, 5.23; Found:
C, 52.83; H, 3.04; N, 13.60; S, 5.26.
210 C54H36 Cl2CrN10O12S2
Violet, λmax in nm (log ε): 524, 3309(N-H), 3087 (C=C-H), 1593, 1527 (C=C, Aromatic), 1434
(N=N), 1345 (C-H, bend), 1152 (C-O), 889, 734 (C=C-H, bend), 626 (Cr-N). Anal. Calcd. For
C54H36 Cl2CrN10O12S2; C, 53.87; H, 3.01; N, 11.63; S, 5.33; Found: C, 53.80; H, 3.14; N, 11.40;
S, 5.41.
214 C56H42CrN10O12S2
Dark Brown, λmax in nm (log ε): 522, 3313 (NH, str), 3047 (C=C-H), 2931 (C-H, str), 1650,
1565, 1544 (C=C, Aromatic), 1443 (N=N), 1332 (C-H, bend), 1118(C-O), 997, 834, 732 (C=C-
H, bend), 631(Cr-N). Anal. Calcd. For C56H42CrN10O12S2; C, 57.83; H, 3.64; N, 12.04; S, 5.51;
Found: C, 57.65; H, 3.76; N, 11.93; S, 5.56.
218 C58H46CrN10O14S2
Light pink, λmax in nm (log ε): 510, 3293 (NH, str), 3168 (C=C-H), 3051 (C=C-H), 2954 (CH2),
2863 (C-H), 1590, 1531(C=C, Aromatic), 1439 (N=N), 1337 (C-H, bend), 1148 (C-O), 828
(C=C-H, bend), 621(Cr-N). Anal. Calcd. For C58H46CrN10O14S2; C, 56.95; H, 3.79; N, 11.45; S,
5.24; Found: C, 56.80; H, 3.85; N, 11.10; S, 5.35.
226 C58H44Cl2CrN10O16S2
Dark Brown, λmax in nm (log ε): 510, 3299(NH, str), 3058(C=C-H), 1590, 1547 (C=C aromatic),
1444(N=N), 1340 (C-H), 1220 (S=O), 1162 (C-O), 868, 708, 683 (C=C-H, bend), 616(Cr-N).
Anal. Calcd. For C58H44Cl2CrN10O16S2; C, 52.61; H, 3.35; N, 10.58; S, 4.84; Found: C, 52.30; H,
3.41; N, 10.18; S, 4.88.
57
3.5 General Scheme-2 for the Synthesis of Pyrazolone Series of Dyes
3.5.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP)
1-(p-sulphophenyl-3-methyl-5-pyrazolone (1) (25.4 g, 0.1 mol) was suspended in H2O (250 mL).
Hydrochloric acid (45 mL) was added to this well stirred suspension. The reaction mixture was
cooled to 0-5°C in an ice bath. A solution of NaNO2 (6.9 g, 0.1 mol) in H2O (25 mL) previously
cooled to 0°C, was then added over a period of 35 minutes with stirring. The stirring was
continued for an hour maintaining the same temperature, with a positive test for nitrous acid.
Later on the excess of nitrous acid was destroyed with required amount of sulphamic acid. The
Nitroso (Oxime) was filtered after salting out. The nitroso was reduced by stirring in 200mL
water containing 85mL HCl and 23g Zinc metal at boil for 4h. At the completion of reaction, pH
of the reaction was reduced to zero with conc.HCl, and precipitated the 1(p-sulphophenyl) -3-
methyl-4-amino pyrazolone was processed further for diazotization.
3.5.2 Diazotization and Coupling with Pyrazolones:
To a well stirred ice jacketed aqueous suspention of 3.05g 1-(p-sulfophenyl)-3-methyl-4-amino -
5-pyrazolone hydrochloride at 0-5 oC, was added 0.7g sodium nitrite and 3.5 mL Conc.HCl. The
reaction mixture was vigorously stirred for 4h at the above temperature to achieve the requisite
diazonium salt.
For the synthesis of dye from diazonium compound of 1-(p-sulfophenyl)-3-methyl-4-amino-5-
pyrazolones, it was coupled at 15-25 oC with 0.010 mol (1.74g) 1-phenyl-3-methyl-5-
pyrazolone (2a) aqueous solution (200mL) containing 0.45g NaOH. The coupling was facilitated
using sodium carbonate as acid binding agent. The reaction mixture was given 4.5h to complete
the coupling at 0-5o
C. The dye was brought to room temperature; pH was reduced upto 4.5 by
HCl, filtered and dried in oven at 70-75o
C till constant weight was obtained with percentage
yield of 87%. By adopting the same procedure other dyes 3b-g were prepared from couplers 2b-g
(scheme 1, scheme 2).
58
3.5.3 Metallization of Pyrazolone Acid Dyes
For the synthesis of metal complex (Chromium complex), pH of 12.5mL of dye 3a was reduced
to 6.5 with HCl. Then it was heated to 100oC and to it 2.5mL solution of Chromium triacetate
containing 0.00125mol Cr+3
was added drop wise. Mixing and heating at this temperature was
continued for further 1.0 hour till the metallization was completed as shown by the comparative
TLC. The dye was cooled to room temperature; its pH was reduced to 1.0 with conc. HCl. The
dye was salted out with sodium chloride which was subsequently filtered and dried in oven at 80
oC till constant weight.
Similarly Iron (II) and Copper (II) complexes of dye 3a were prepared by treating them with
FeSO4.7H2O and CuSO4.5H2O at temperature 55-70 oC with mole ratio 1:1 (Iron and Copper
complexes). In this way complexes 5a-g, 6a-g and 7a-g were synthesized from respective dye
ligands.
229 (C20H18N6O8S2)
Orange, (82%). λmax in nm (log ε): 450. FTIR (KBr, cm-1
) νmax: 3473 (OH, NH), 3060 (C-H, str),
2932 (C-H. aliphatic), 1665, 1591, 1535 (C=C aromatic), 1469 (N=N, str), 1325(C-H, bend),
1159 (S=O str), 1070, C-O), 827 (C=C, bend). 1H-NMR (300 MHz, DMSO-d6) δ: 10.00 (s, 1H,
OH), 9.13 (s, 1H), 8.67 (s, 1H, OH), 7.98 (d, 1H), 7.90 (t, 1H), 7.84 (d, 2H), 7.73 (s, 1H, SO3H),
7.59 (d, 1H), 7.45 (s, 1H), 7.23 (d, 2H), 6.60 (s, 1H, SO3H), 2.64 (s, 3H), 2.60 (s, 3H). 13
C-NMR
(75 MHz, DMSO-d6) δ (ppm): 153.01, 145.60, 145.60, 142.86, 141.25, 137.98, 137.10, 130.32,
129.26, 128.55, 125.56, 119.29, 118.70, 118.34, 13.59. Anal. Calcd. For C28H23N5O6S: C, 44.94;
H, 3.39; N, 15.72; S, 12.00; Found: C, 44.86; H, 3.45; N, 15.47; S, 12.06.
233 C21H20N6O5S
Orange, (93%) λmax in nm (log ε): 450. FTIR (KBr, cm-1
) νmax: 3464 (OH, str), 3062 (C=C-H),
2924 (C-H, str, aliphatic), 1632, 1546 (C=C aromatic), 1447 (N=N, str), 1317 (C-H, bending),
1209 (S=O, str), 1050 (C-O), 875 (Ar-H). 1H-NMR (300 MHz, DMSO-d6 ) δ: 9.75 (s, 1H, OH),
9.66 (s, 1H, OH), 8.08 (d, 2H), 7.98 (d, 2H), 7.71 (d, 1H), 7.58 (s, 1H), 7.24 (t, 1H), 7.00 (d,
1H), 6.68 (s, 1H, SO3H), 2.65 (s, 6H), 2.35 (s, 3H). 13
C-NMR (75 MHz, DMSO-d6) δ (ppm):
153.01, 145.60, 145.60, 141.25, 139.18, 138.29, 137.10, 129.82, 128.63, 125.56, 120.90, 119.17,
118.63, 118.24, 21.21, 13.47. Anal. Calcd. For C21H20N6O5S: C, 53.84; H, 4.30; N, 17.94; O,
17.08; S, 6.84, Found: C, 53.55; H, 4.38; N, 17.70.
59
237 C20H18N6O5S
Reddish Orange, (87%) λmax in nm (log ε): 438. FTIR (KBr, cm-1
) νmax: 3460 (OH, str), 3055
(C=C-H), 2924 (CH2), 1619, 1559 (C=C aromatic), 1448 (N=N, str), 1343(CH2), 1209 (S=O,
str), 1174(C-O), 872 (Ar-H). 1H NMR (300 MHz, DMSO-d6) δ: 9.70 (s, 1H, OH), 8.60 (s, 1H,
OH), 8.01 (d, 2H), 7.60 (d, 2H), 7.33 – 7.28 (m, 5H), 7.17 (s, 1H), 6.67 (s, 1H, SO3H), 2.60 (s,
6H).13
C NMR (75 MHz, DMSO-d6) δ: 153.01, 145.60, 141.25, 138.12, 137.10, 131.28, 129.55,
126.41, 125.56, 122.03, 118.34, 13.19. Anal. Calcd. For C20H18N6O5S: C, 52.86; H, 3.99; N,
18.49; O, 17.60; S, 7.05, Found: C, 52.42; H, 3.95; N, 18.30; S, 7.100.
241 (C20H18N6O8S2)
Tan, (93%) λmax in nm (log ε): 454. FTIR (KBr, cm-1
) νmax: 3468 (OH, str), 3055 (C=C-H), 2926
(C-H, aliphatic), 1629, 1543 (C=C aromatic), 1465 (N=N), 1343(C-H, bend), 1159 (S=O), 883
(Ar-H). 1H-NMR (300 MHz, DMSO-d6) δ: 9.70(s, 2H, OH), 7.90 (d, 4H), 7.65 (d, 4H), 6.69 (s,
1H, SO3H), 2.68 (s, 6H). 13
C-NMR (75 MHz, DMSO-d6) δ (ppm): δ 153.01, 153.01, 145.60,
145.60, 141.25, 137.10, 125.56, 118.81, 118.22, 13.65. Anal. Calcd. For C20H18N6O8S2: C,
44.94; H, 3.39; N, 15.72; S, 12.00, Found: C, 44.85; H, 3.43; N, 15.45; S, 12.09.
245 (C20H17ClN6O5S)
Reddish Orange, (83%). λmax in nm (log ε): 434. FTIR (KBr, cm-1
) νmax: 3476 (OH, str), 3059 (C-
H, str), 2936 (C-H. aliphatic), 1642, 1563 (C=C aromatic), 1441 (N=N, str), 1328 (C-H, bend),
1265 (S=O str), 1050 (C-O), 880 (C=C, bend), 780 (C-Cl). 1H-NMR (300 MHz, DMSO-d6) δ:
9.66 (s, 2H), 9.60 (s, 1H, OH), 8.08 (d, 2H), 7.93 (d, 2H), 7.78 (d, 2H), 7.37 (d, 2H), 6.65 (s, 1H,
SO3H), 2.61 (s, 6H). 13
C-NMR (75 MHz, DMSO-d6) δ (ppm): 153.01, 145.60, 141.25, 137.10,
136.87, 132.39, 129.30, 125.56, 123.55, 118.76, 118.10, 13.67. Anal. Calcd. For
C20H17ClN6O5S: C, 49.13; H, 3.50; Cl, 7.25; N, 17.19; S, 6.56; Found: C, 48.95; H, 3.42; Cl,
7.16; N, 17.10; S, 6.67;
249 (C20H16Cl2N6O8S2)
Orange, (81%). λmax in nm (log ε): 446. FTIR (KBr, cm-1
) νmax: 3474 (OH, str), 3050 (C-H, str),
2924 (C-H. aliphatic), 1660, 1538 (C=C aromatic), 1445 (N=N, str), 1328 (C-H, bend), 1272
(S=O str), 1040 (C-O), 865 (C=C, bend), 783 (C-Cl). 1H-NMR (300 MHz, DMSO-d6) δ: 9.72 (s,
1H, OH), 9.57 (s, 1H, OH), 8.17 (d, 2H), 8.15 (d, 2H), 7.81 (d, 1H), 7.68 (s, 1H, SO3H), 7.35 (d,
1H), 6.69 (s, 1H, SO3H), 2.60 (m, 6H). 13C-NMR (75 MHz, DMSO-d6) δ (ppm): δ 153.01,
150.76, 145.60, 143.96, 141.25, 138.89, 138.10, 137.10, 134.81, 130.76, 129.92, 125.56, 121.76,
60
119.10, 118.45, 118.15, 13.53. Anal. Calcd. For C20H16Cl2N6O8S2: C, 39.81; H, 2.67; Cl, 11.75;
N, 13.93; S, 10.63; Found: C, 39.70 H, 2.63; Cl, 11.68; N, 13.75; S, 10.72.
253 (C20H16N6O10S2)
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3565, 3485 (COOH, OH, str),
3058 (C-H, str), 2930 (C-H, aliphatic), 1657, 1547 (C=C aromatic), 1447 (N=N, str), 1325(C-H,
bend), 1264 (S=O str), 1035 (C-O), 853 (C=C, bend). 1H-NMR (300 MHz, DMSO-d6) δ: 12.18
(s, 1H, COOH), 10.30 (s, 1H, OH), 7.89 (d, 2H), 7.71-7.76 (m, 4H), 7.68 (d, 1H), 5.95 (s, 1H),
2.29 (s, 3H).13
C-NMR (75 MHz, DMSO-d6) δ (ppm) : 163.73, 163.36, 154.02, 146.80, 144.76,
143.54, 138.65, 126.88, 126.78, 122.42, 121.55, 121.48, 117.06, 89.85, 12.25. Anal. Calcd. For
C20H16N6O10S2: C, 42.55; H, 2.86; N, 14.89; S, 11.36; Found: C, 42.30; H, 2.80; N, 14.73; S,
11.43.
231- C20H22FeN6O11S2
Brown, λmax in nm (log ε): 480, 3274.5 (NH, str), 3021(C=C-H), 2922(CH2), 2851, 1593, 1541,
1489 (C=C aromatic), 1438 (N=N), 1382 (C-H, bend), 1309 (S=O), 1151 (C-O), 915(C=C-H,
bend), 590 (Fe-N, str). Anal. Calcd. For C20H22FeN6O11S2; C, 49.78; H, 3.87; N, 10.75; S, 4.92.
Found: C, 49.67; H, 3.93; N, 10.70; S, 4.98
235- C20H20FeN6O13S2
Dark Brown, λmax in nm (log ε): 475, 3274(NH, str), 3021(C=C-H), 2922(CH2), 2851, 1593,
1541, 1489 (C=C aromatic), 1436(N=N), 1382 (C-H, bend), 1151 (C-O), 827 (C=C-H, bend),
743(C=C-H, bend), 585 (Fe-N, str). Anal. Calcd. For C27H24FeN6O11S; C, 46.57; H, 3.47; Fe,
8.02; N, 12.07; S, 4.60. Found: C, 46.51; H, 3.50; N, 12.00; S, 4.68.
239 C20H22FeN6O8S
Dark Brown, λmax in nm (log ε): 493, 3289 (NH, str), 3050(C=C-H), 1689 (C=O), 1559(C=C
aromatic), 1448(N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 887, 870, 708 (C=C-H, bend), 589
(Fe-N, str). Anal. Calcd. For C20H22FeN6O8S; C, 47.28; H, 3.53; Fe, 8.14; N, 10.21; S, 4.67. ;
Found: C, 47.36; H, 3.59; Fe, 8.10; N, 10.16; S, 4.70.
243 C21H24FeN6O8S
Brown, λmax in nm (log ε): 480, 3296(NH, str), 3050(C=C-H), 1593, 1559(C=C aromatic),
1448(N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 870, 708, 687 (C=C-H, bend), 578 (Fe-N,
str). Anal. Calcd. For C21H24FeN6O8S; C, 50.54; H, 4.09; N, 10.52; S, 4.82; Found: C, 50.50; H,
4.19; Fe, 8.30; N, 10.43; S, 4.86.
61
247 C20H22FeN6O11S2
Brown, λmax in nm (log ε): 479, 3296 (N-H, str), 3052(C=C-H), 1619, 1559 (C=C aromatic),
1448 (N=N), 1343 (C-H), 1209 (S=O), 1174 (C-O), 870,739,708,687(C=C-H, bend), 583 (Fe-N,
str). Anal. Calcd. For C20H22FeN6O11S2 ; C, 50.08; H, 4.20; N, 10.07; S, 4.61; Found: C, 50.00;
H, 4.28; N, 10.00; S, 4.67
251 C20H21ClFeN6O8S
Grey, λmax in nm (log ε): 482, 3276 (NH, str), 3170 (C=C-H), 3054 (C=C-H), 2950 (CH2), 2853
(C-H), 1595, 1541(C=C, Aromatic), 1489 (N=N), 1330 (C-H, bend), 1157(C-O), 827 (C=C-H,
bend), 586 (Fe-N, str). Anal. Calcd. For C20H21ClFeN6O8S; C, 46.70; H, 3.78; N, 9.39; S, 4.30;
Found: C, 46.61; H, 3.84; N, 9.30; S, 4.37.
232 C20H18CuN6O9S2
Tan, λmax in nm (log ε): 509, 3315 (NH, str), 3127(C=C-H), 1623, 1587, 1541(C=C, Aromatic),
1459 (N=N), 1343 (C-H), 1200 (S=O),1174 (C-O), 884(C=C-H, bend), 530 (Cu-N). Anal. Calcd.
For C20H18CuN6O9S2; C, 49.20; H, 3.82; N, 10.63; S, 4.86; Found: C, 49.11; H, 3.86; N, 10.54;
S, 4.89.
236 C20H16CuN6O11S2
Violet, λmax in nm (log ε): 525, 3315(NH, str), 3123(C=C-H), 1541, 1489 (C=C, Aromatic),
1457(N=N), 1340 (C-H, bend), 1202 (S=O),1159 (C-O), 918,827,741 (C=C-H, bend), 536 (Cu-
N). Anal. Calcd. For C20H16CuN6O11S2; C, 46.06; H, 3.44; N, 11.94; S, 4.55; Found: C, 45.90;
H, 3.50; N, 11.81; S, 4.65.
240 C20H18CuN6O6S
Violet, λmax in nm (log ε): 524, 3313(NH, str), 3052(C=C-H), 2927 (C-H, str), 1654, 1555, 1541
(C=C, Aromatic), 1449 (N=N), 1332(C-H, bend), 1118(C-O), 997,834,732 (C=C-H, bend), 529
(Cu-N). Anal. Calcd. For C20H18CuN6O6S; C, 46.76; H, 3.49; N, 10.10; S, 4.62; Found: C,
46.65; H, 3.54; N, 10.01; S, 4.68.
244 C21H20CuN6O6S
Dark Brown, λmax in nm (log ε): 525, 3380 (NH, str), 2924(C-H, str), 1597, 1526(C=C), 1425
(N=N), 1340(C-H, bend), 1157(C-O), 1120(C-O), 834,788,741(C=C-H, bend), 526 (Cu-N).
Anal. Calcd. For C21H20CuN6O6S; C, 49.96; H, 4.04; N, 10.40; S, 4.76; Found: C, 49.88; H,
4.09; N, 10.32; S, 4.85.
62
248 C20H18CuN6O9S2
Tan, λmax in nm (log ε): 510, 3423 (OH, str), 3315 (N-H), 3054 (C=C-H), 2981 (C-H), 1533,
1490 (C=C, Aromatic), 1431(N=N), 1338 (C-H, bend),1157 (C-O) , 833, 788, 730 (C=C-H,
bend), 533 (Cu-N). Anal. Calcd. For C20H18CuN6O9S2; C, 49.53; H, 4.16; N, 9.96; S, 4.56.
Found: C, 49.47; H, 4.22; N, 9.81; S, 4.61.
252 C20H17ClCuN6O6S
Dark Brown, λmax in nm (log ε): 509, 3319 (N-H), 3087(C=C-H), 1597, 1522 (C=C, Aromatic),
1429 (N=N), 1340 (C-H, bend), 1157(C-O), 889,734 (C=C-H, bend), 525 (Cu-N). Anal. Calcd.
For C20H17ClCuN6O6S C, 46.22; H, 3.75; N, 9.29; S, 4.25; Found: C, 46.10; H, 3.78; N, 9.20; S,
4.30.
230 C40H32CrN12O16S4
Pink, λmax in nm (log ε): 511, 3311(N-H), 3088 (C=C-H), 1595, 1524 (C=C, Aromatic), 1423
(N=N), 1317 (C-H, bend), 1209 (S=O), 1148 (C-O), 998, 732 (C=C-H, bend), 618 (Cr-N). Anal.
Calcd. For C40H32CrN12O16S4; C, 57.14; H, 3.37; N, 12.34; S, 5.65; Found: C, 57.10; H, 3.40;
N, 12.26; S, 5.71.
234 C40H29CrN12O20S4
Violet Brown, λmax in nm (log ε): 522, 3305 (N-H), 3084(C=C-H), 2955 (C-H), 1599, 1522
(C=C, Aromatic), 1429 (N=N), 1340 (C-H, bend), 1123(C-O), 831,734 (C=C-H, bend), 629 (Cr-
N). Anal. Calcd. For C40H29CrN12O20S4; C, 52.94; H, 2.96; N, 13.72; O, 20.90; S, 5.23; Found:
C, 52.83; H, 3.04; N, 13.60; S, 5.26.
238 C40H33CrN12O10S2
Violet, λmax in nm (log ε): 524, 3309(N-H), 3087 (C=C-H), 1593, 1527 (C=C, Aromatic), 1434
(N=N), 1345 (C-H, bend), 1152 (C-O), 889, 734 (C=C-H, bend), 626 (Cr-N). Anal. Calcd. For
C40H33CrN12O10S2; C, 53.87; H, 3.01; N, 11.63; S, 5.33; Found: C, 53.80; H, 3.14; N, 11.40; S,
5.41.
242 C42H37CrN12O10S2
Dark Brown, λmax in nm (log ε): 522, 3313 (NH, str), 3047 (C=C-H), 2931 (C-H, str), 1650,
1565, 1544 (C=C, Aromatic), 1443 (N=N), 1332 (C-H, bend), 1118(C-O), 997, 834, 732 (C=C-
H, bend), 631(Cr-N). Anal. Calcd. For C42H37CrN12O10S2; C, 57.83; H, 3.64; N, 12.04; S, 5.51;
Found: C, 57.65; H, 3.76; N, 11.93; S, 5.56.
63
246- C40H33CrN12O16S4
Light pink, λmax in nm (log ε): 510, 3293 (NH, str), 3168 (C=C-H), 3051 (C=C-H), 2954 (CH2),
2863 (C-H), 1590, 1531(C=C, Aromatic), 1439 (N=N), 1337 (C-H, bend), 1148 (C-O), 828
(C=C-H, bend), 621(Cr-N). Anal. Calcd. For C40H33CrN12O16S4; C, 56.95; H, 3.79; N, 11.45; S,
5.24; Found: C, 56.80; H, 3.85; N, 11.10; S, 5.35.
250 C40H31Cl2CrN12O10S2
Dark Brown, λmax in nm (log ε): 510, 3299(NH, str), 3058(C=C-H), 1590, 1547 (C=C aromatic),
1444(N=N), 1340 (C-H), 1220 (S=O), 1162 (C-O), 868, 708, 683 (C=C-H, bend), 616(Cr-N).
Anal. Calcd. For C40H31Cl2CrN12O10S2; C, 52.61; H, 3.35; N, 10.58; S, 4.84; Found: C, 52.30; H,
3.41; N, 10.18; S, 4.88.
3.6 General Scheme-3 for the Synthesis of Naphthol Series of Dyes
In this series of dyes, 20 dyes were synthesized from five different naphthols.The naphthols were
β-naphthol, Schaeffer’s acid, R-acid, H-acid and N-phenyl-J-acid. Four dyes were prepared with
each naphthol. The first dye was un-metalized one, while other three were chromium, iron and
copper complexes respectively. The chromium complexes were of 2:1 type. The detail of
metallization for naphthol dyes synthesis is given in General Scheme-3.
OH2OH2
H2O
HO3S
N
N
CH3
O
N N
M O R3
R1
R2
R1=R2=R3=H, Dye=257,
R1=R3=H, R2=SO3H, Dye=261
R1=H, R2=R3=SO3H, Dye=265
R1=NH2, R2=R3=SO3H, Dye=269
R1=H, R3=SO3H, R2=NHC6H5, Dye=273,
M= Fe+2,259, 263, 267, 271, 275
M=Cu+2, 260, 264, 268, 272, 276
HO3S
N
N
CH3
OH
N N
HO R3
R1
R2
NN
CH3
O
HO3SN N
O
NN
CH3
O
HO3SN N
OCr-
R2
R2
R3
R3
R1
R1
M= Cr+3, 258, 262, 266, 270, 274
General Scheme-3; The synthesis of naphthol series of dyes (metallization step only).
64
3.6.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP)
SPMP [1(4-sulphophenyl)3-methyl-2-pyrazoline-5- one] (25.4g, 0.1 mole) was taken in 250mL
H2O. Hydrochloric acid (45 mL) was added to this well stirred suspension. The reaction mixture
was cooled to 0°C in an ice bath. A solution of NaNO2 (6.9g, 0.1mol) in 25mL water, previously
cooled to 0°C, was then added over a period of 35 minutes with stirring. Mixing was continued
for one hour at the same temperature, keeping an excess of nitrous acid. Later on the excess of
nitrous acid was destroyed with the requisite amount of sulphamic acid. The Nitroso (Oxime)
was salted out with 15% salt and filtered.
3.6.2 Reduction
The Nitroso (Oxime) derivative was reduced in 200mL water containing 85mL HCl and 23g
Zinc metal at the boil (103-105°C) to form SPMP amine hydrochloride.
3.6.3 Diazotization
SPMP amine hydrochloride was diazotized by adding an aqueous solution of NaNO2 (6.9g
dissolved in 250mL of water) at -5 to -2°C.The nitrous acid formed in situ converted the SPMP
amine hydrochloride to the diazonium compound.
3.6.4 Coupling
The diazonium salt formed above was coupled with a cold solution of β-naphthol (14.4g=0.1mol
previously dissolved in 200mL boiling water containing 4.5g=0.1125mol NaOH). The coupling
of β-naphthol with the diazonium compound was done at 15-20°C using NaOH as an acid
binding agent. H-acid was used as an external indicator to check the completion of coupling
reaction. By adopting the same procedure other dyes (3b-g) were prepared from couplers
(Schaeffer’s Acid, R-acid, H-acid and N-phenyl J-acid) (General Reaction Scheme-3 above).
3.6.5 Metallization of naphthol acid dyes
For the preparation of metal complex dye (chromium based complex), the pH of 125mL of dye
1a was lowered to 6.5 with HCl (37%) and heated to 100°C. 2.5mL solution of chromium
triacetate (0.00125mol Cr3+
) was added slowly drop-wise. Mixing with heating at 100°C was
continued for 1.0 hour till metallization was completed as confirmed by comparative TLC. The
dye solution was cooled to 30°C; its pH was lowered to 1.0 with HCl (37%). The dye was
separated by salting out with sodium chloride, filtered and oven dried at 80°C to constant weight.
Similarly iron (II) and copper (II) metal complexes of dye 3a were synthesized by treating them
with appropriate solutions of FeSO4.7H2O and CuSO4.5H2O at 55-70°C with a mole ratio 1:1
65
1:1(iron and copper complexes). In this way complexes 1b-d, 2b-d, 3b-d, 4b-d and 5a-d were
prepared from the respective dye ligands. Four dye samples were prepared with each coupler.
The first being an un-metallized dye and the other three being chromium, iron and copper
complexes respectively. The chromium complexes were of the 2:1 type. In case of chromium,
three water molecules are replaced with one molecule of the same dye to form a 2:1 metal
complex.
257 C20H16N4O5S
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3429 (H2O, OH str.), 3336(NH
str.), 3050(C=C-H str.), 1597(C=C aromatic), 1431(N=N str.), 1243(CH2str.), 1170(C-O str.),
1008(S=O), 836(Ar-H).
258 C40H29CrN8O10S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3430(H2O, OH str.), 3220(NH
str.), 3050 (C=C-H str.), 2924 (CH2 str.), 1675(C=O str.), 1589 (C=C aromatic), 1500 (N=N
str.), 1418 (C-H bend.), 1369 (CH2 str.), 1123 (C-O str.), 1004(S=O), 812(Ar-H).
259 C20H20FeN4O8S
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3350 (H2O, OH str.), 3235 (NH
str.), 3052 (C=C-H str.), 1619, 1559 (C=C aromatic, C=N, N=N str.), 1431 (CH. bend.), 1121
(C-O str.), 1004 (S=O), 738(Ar-H).
260 C20H20CuN4O8S
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3397 (H2O, OH, NH str.), 3050
(C=C-H str.), 2924 (CH2 str.), 1619, 1559 (C=C aromatic), 1435 (N=N str.), 1367 (CH2str.),
1123 (C-O str.) 1006 (S=O), 814(Ar-H).
261-C20H16N4O8S2
3431(H2O, OH, NH str.), 2931(CH2 str.), 1597 (C=C aromatic, C=N, N=N str.), 1179 (C-O-C
str.), 1006 (S=O), 810(Ar-H).
262 C40H29CrN8O16S4
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3337(H2O, OH, NH str.), 2924
(CH2 str.), 1616, 1578(C=C aromatic, N=N str.), 1399 (O H bend.), 1036 (S=O), 810(Ar-H).
66
263 C20H20FeN4O11S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3400 (H2O, OH str.), 3172 (NH
str.), 1619, 1557 (C=C aromatic, C=N, N=N str.), 1157 (C-O str.), 1036 (S=O), 872 (Ar-H).
264 C20H20CuN4O11S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3283(H2O, OH, NH str.), 1597
(C=C aromatic), 1496 (N=N str.), 1062 (S=O), 1164 (C-O str.), 882 (Ar-H).
265 C20H16N4O11S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3391 (H2O, OH, NH str.), 3015
(C=C-H str.), 1619, 1552 (C=C aromatic, C=N), 1498 (N=N str.), 1125 (C-O str.), 1004 (S=O),
827(Ar-H).
266 C40H29CrN8 O22S6
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3328 (H2O, OH, NH str.), 2922
(CH2 str.), 1590(C=C aromatic, C=N, N=N str.), 1399 (OH bend.), 1179 (C-O str.), 1006 (S=O),
838(Ar-H).
267 C20H20FeN4O14S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3399 (H2O, OH, NH str.),
2920(CH2 str.), 1619, 1559 (C=C aromatic, C=N), 1483(N=N str.), 1121 (C-O-C str.), 1004
(S=O), 829(Ar-H).
268 C20H20CuN4O14S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3365(H2O, OH str.), 3202 (NH
str.), 3050 (C=C-H str.), 1619, 1559 (C=C aromatic, C=N,N=N str.), 1174 (C-O str.), 1034
(S=O), 872(Ar-H).
269 C20H17N5O11S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3449(H2O, OH str.), 3298(NH
str.), 3049 (C=C-H str.), 2879(CH2 str.), 1619, 1595 (C=C aromatic, C=N), 1498 (N=N str.),
1174 (C-O str.), 1041 (S=O), 872(Ar-H).
67
270 C40H31CrN10O22S6
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3457 (H2O, OH, NH str.),
3071(C=C-H str.), 2881(CH2 str.), 1619, 1597(C=C aromatic, C=N), 1500 (N=N str.), 1369
(CH2 str.), 1166 (C-O str.), 1148 (C-C str.), 1041(S=O), 890 (Ar-H)
271 C20H21FeN5O14S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3505 (H2O, OH str.), 3298(NH
str.), 3050 (C=C-H str.), 1619, 1559 (C=C aromatic, C=N, N=N str.), 1165 (C-O str.),
1038(S=O), 872 (Ar-H).
272 C20H21CuN5O14S3
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3505 (H2O, OH str.), 3298(NH
str.),3050 (C=C-H str.), 2924 (CH2 str.), 1619, 1559 (C=C aromatic, C=N,N=N str.), 1166(C-O
str.), 1038 (S=O), 838 (Ar-H).
273 C26H21N5O8S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3304 (H2O, OH str.), 3155 (NH
str.), 3050 (C=C-H str.), 2924 (CH2 str.), 1586 (C=C aromatic, C=N), 1495 (N=Nstr.), 1394
(CH2 str.), 1155 (C-O str.), 1036 (S=O), 898 (Ar-H).
274 C52H39CrN10O16S4
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3586(H2O, OH, NH str.),
3050(C=C-H str.), 1619, 1578 (C=C aromatic, C=N), 1498 (N=N str.), 1399 (CH2str.), 1177(C-
O str.), 1041 (S=O), 881 (Ar-H).
275-C26H25FeN5O11S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3363 (H2O, OH, NH str.), 2924
(CH2 str.), 1619, 1578 (C=C aromatic, C=N),1494(N=N str.), 1310 (CH2str.), 1176 (C-O str.),
1038(S=O), 834 (Ar-H).
276 C26H25CuN5O11S2
Orange, (84%). λmax in nm (log ε): 505. FTIR (KBr, cm-1
) νmax: 3367 (H2O, OH, NH str.),
2924(CH2 str.), 1619, 1559 (C=C aromatic, C=N), 1492(N=N str), 1308(CH2str.), 1177 (C-O
str.), 1038 (S=O), 838 (Ar-H).
68
3.7 General Scheme-4; The Synthesis of p-substituted-Phenol, Resorcinol and Bisphenol
Dyes
Synthesis of these acid dyes and their metal complexes involved three step procedure including
synthesis of diazo of SPMP, its coupling with desired couplers and metallization which is as
follows:
General Scheme-4a; Synthesis of p-substituted-Phenol, Resorcinol and Bisphenol Dyes, their
Iron and Copper complexes (Metallization step only).
69
General Scheme-4b; Synthesis of p-substituted-Phenol, Resorcinol and Bisphenol Dyes and
their Chromium complexes (Metallization step only).
3.7.1 Nitrosation of p-Sulphophenyl-3-methyl-5-pyrazolone (SPMP)
1-(p-sulphophenyl-3-methyl-5-pyrazolone (144) (25.4 g, 0.1 mol) was suspended in H2O (250
mL). Hydrochloric acid (45 mL) was added to this well stirred suspension. The reaction mixture
was cooled to 0-5°C in an ice bath. A solution of NaNO2 (6.9 g, 0.1 mol) in H2O (25 mL)
previously cooled to 0°C, was then added over a period of 35 minutes with stirring. The stirring
was continued for an hour maintaining the same temperature, with a positive test for nitrous acid.
Later on the excess of nitrous acid was destroyed with required amount of sulphamic acid. The
Nitroso (Oxime) was filtered after salting out. Then oxime was reduced by stirring in 200mL
water containing 85mL HCl and 23g Zinc metal at boil for 4hours till the reaction mass was
colorless.
70
3.7.2 Diazotization of SPMP and Coupling with Phenol Derivatives
To the well stirred ice jacketed aqueous solution (2.69 g) of 1-(p-sulphophenyl-3-methyl-4-
amino pyrazolone (at 0-5 oC) was added Conc. HCl (3.5 mL) and sodium nitrite solution (0.7 g
in 2mL H2O). The reaction mixture was vigorously stirred for 1h at the above mentioned
temperature to obtain the diazonium salt of 1-(p-sulphophenyl)-3-methyl-4-amino pyrazolone.
The diazonium compound formed in this way was coupled to various coupler mentioned
previously to synthesize our dyes. Thus 1.285 g (0.010 mol) 4-Chlorophenol (5a) was dissolved
in 200 mL water containing 0.45 g NaOH and coupled with prepared diazo. The coupling was
facilitated using sodium carbonate as an acid binding agent. The reaction mixture was given 4-5
hour to complete the coupling at 30-35 oC. The dye was cooled to room temperature. Its pH was
reduced to 4.5 by HCl and filtered. The cake was dried in oven at 70-75 oC till constant weight.
By adopting the same procedure other dyes 6b-f were prepared from couplers 5b-f as shown in
(Scheme-4a and 4b).
3.7.3 Metallization of Phenolic Acid Dyes.
For the synthesis of metal complexes (Iron complex), pH of 25 mL (0.005mole) of dye 6a was
reduced to 6.5 with HCl. Then it was heated to 70oC and to it 5 mL (0.005 mole Fe
2+) solution of
ferrous sulfate (FeSO4.7H2O) was added drop wise. Mixing and heating at this temperature was
continued for further 1.0 hour till the metallization was completed, as shown by the comparative
TLC. The dye was cooled to room temperature; its pH was reduced to 1.0 with conc. HCl. Then
it was salted out with sodium chloride, filtered and dried in oven at 80 oC till constant weight.
Similarly copper (II) complexes of dye 6a were prepared by treating dye with CuSO4.5H2O at
65-70 oC with metal to ligand mole ratio 1:1. In this way complexes 7a-l were synthesized from
respective dye ligands.
277 (C16H13ClN4O5S)
Orange, (76%) λmax (nm): 460. FTIR (KBr, cm-1
) νmax: 3255 (OH str.), 3050 (C=C-H str.), 2927
(CH2 str.), 1653 (C=O str.), 1595, 1541 (C=C aromatic, C=N), 1498 (N=N str.),1422, 1340
(SO3H str., CH2 bend.), 1236, 1155 (C-C, C-O str.), 1000 (S=O str.), 833 (Ar-H), 790(C-Cl str.).
1HNMR (300 MHz, DMSO-d6) δ: 8.07 (1H, d J=2.35 Hz), 7.95 (2H, d J=8.6 Hz), 7.83-7.90 (1H,
71
m), 7.68 (2H, d J=8.6 Hz), 6.65 (1H, d, J=9.1 Hz), 2.20 (3H, s).13
C-NMR (75 MHz DMSO-d6) δ
(ppm) : 158.54, 156.64, 147.93, 147.37, 143.21, 139.93, 125.43, 124.41, 119.45, 118.06, 116.22
12.45. Anal. Calcd. For C16H13ClN4O5S: C, 47.01; H, 3.21; N, 13.71; S, 7.84 Found: C, 47.05;
H, 3.30; N, 13.59; S, 7.79.
281 (C16H13N5O7S)
Dark Brown, (83%). λmax (nm): 480. FTIR (KBr, cm-1
) νmax: 3388 (OH str.), 2924 (CH2 str.),
1666 (C=C str.), 1593 (C=C aromatic, C=C), 1498, 1476 (N=N, NO2str.), 1267, 1172 (C-O str.),
1034 (C-OC str.), 821 (Ar-H). 1HNMR (300 MHz, DMSO-d6) δ: 8.15 (1H, d J=2.4 Hz), 7.942
(2H, d J=8.7 Hz), 7.81-7.92 (1H, m), 7.65 (2H, d J=8.7 Hz), 6.38 (1H, d, J=9.3 Hz), 2.27 (3H,
s).13
C-NMR (75 MHz DMSO-d6) δ (ppm): 158.0, 155.28, 148.32, 147.57, 144.58, 138.72,
128.18 126.86, 126.24, 118.19, 117.06, 116.17, 12.14. Anal. Calcd. For C16H13N5O7S: C, 45.83;
H, 3.12; N, 16.70, S, 7.64; Found: C, 45.78; H, 3.20; N, 16.58, S, 7.57.
285 (C16H14N4O8S2)
Orange, (84%). λmax (nm): 460. FTIR (KBr, cm-1
) νmax: 3389 (OH str), 3086 (C=C-H str.), 1638
(N-H bend.), 1619, 1597 (C=C aromatic), 1541 (N=N str.), 1500 (N-H bend.), 1340 (SO3H, CH2
str.), 1185 (C-O str.), 818 (Ar-H). 1HNMR (300 MHz, DMSO-d6) δ: 11.87 (1H, s, O-H), 8.10
(1H, d J=2.6 Hz), 7.93 (2H, d J=8.6 Hz), 7.79-7.90 (1H, m), 7.67 (2H, d J=8.6 Hz), 6.90 (1H, s,
SO3H), 6.58 (1H, d, J=9.5 Hz), 2.27 (3H, s).13
C-NMR (75 MHz DMSO-d6) δ (ppm) : 159.12,
156.48, 147.72, 147.17, 145.23, 141.33, 138.62, 125.68, 124.42, 117.19, 116.96, 116.43 11.81.
Anal. Calcd. For C16H14N4O8S2: C, 42.29; H, 3.11; N, 12.33, S: 14.11 Found: C, 42.24; H, 3.20;
N, 12.21, S: 14.04.
289 (C16H13N5O10S2)
Orange, (81%). λmax (nm): 520. FTIR (KBr, cm-1
) νmax: 3449 (OH str.), 3050 (C=C-H str.), 1653
(C=C str. NH bend), 1619, 1541 (C=C aromatic), 1498 (N=N str.), 1338 (SO3H, CH2 str.), 1183
(C-O str.), 1008 (S=O), 840 (Ar-H). 1HNMR (300 MHz, DMSO-d6) δ: 11.33 (1H, s, O-H), 8.15
(1H, d J=2.4 Hz), 7.99 (1H, d J=2.4 Hz), 7.922 (2H, d J=8.7 Hz), 7.63 (2H, d J=8.7 Hz), 2.23
(3H, s).13
C-NMR (75 MHz DMSO-d6) δ (ppm) : 157.05, 156.28, 149.25, 147.63, 144.28, 142.76,
140.92, 127.16, 125.54, 119.19, 116.56, 115.20 12.14. Anal. Calcd. For C16H13N5O10S2: C,
38.48; H, 2.62; N, 14.02; S, 12.84; Found: C, 38.37; H, 2.69; N, 13.96; S, 12.88.
72
297 (C32H26N8O12S3)
Orange, (80%). λmax (nm): 420. FTIR (KBr, cm-1
) νmax: 3395 (, OH , NH str.), 3050 (C=C-H str.),
2926 (CH2 str.), 1619, 1586 (C=C aromatic, C=N), 1498 (N=N str.), 1125 (C-O str.), 1008
(S=O), 872 (Ar-H). 1HNMR (300 MHz, DMSO-d6) δ: 11.67 (1H, s, O-H), 7.91 (2H, d J=8.7
Hz), 7.81-7.92 (1H, m), 7.69 (2H, d J=8.7 Hz), 6.90 (1H, d, J=9.4 Hz), 6.78 (1H, s), 6.62 (1H, s,
SO3H), 6.59 (1H, d, J=9.4 Hz), 2.51(3H, s), 1.469 (6H, s).13
C-NMR (75 MHz, DMSO-d6) δ
(ppm) : 157.56, 154.89, 148.97, 154.64, 144.47, 143.44, 142.29, 141.31, 138.88, 137.90, 129.96,
128.05, 127.74, 126.78, 119.85, 118.63, 117.64, 115.79, 115.64, 115.13, 115.02, 41.19, 30.83,
11.59. Anal. Calcd. For C32H26N8O12S3: C, 47.40; H, 3.23; N, 13.82; S, 11.86; Found: C, 47.46;
H, 3.31; N, 13.56; S, 11.80.
301 (C35H32N8O10S2)
Brown, (83%). λmax (nm): 450. FTIR (KBr, cm-1
) νmax: 3464 (OH, NH str.), 2963 (CH2 str.),
1653, 1593 (C=C aromatic), 1490(N=N str.), 1338 (SO3H str.), 1213, 1153, 1120 (C-C str.),
1002 (S=O), 872 (Ar-H). 1H-NMR (300 MHz, DMSO-d6) δ: 11.30 (1H, s, O-H), 7.94 (2H, d
J=8.7 Hz), 7.82-7.93 (1H, m), 7.67 (2H, d J=8.7 Hz), 6.98 (1H, d, J=9.4 Hz), 6.81 (1H, s), 6.58
(1H, d, J=9.4 Hz), 6.42 (1H, s, SO3H), 2.47 (3H, s).13
C-NMR (75 MHz, DMSO-d6) δ (ppm) :
158.77, 155.9, 147.61, 145.61, 143.86, 143.25, 141.63, 139.81, 136.75, 130.25, 127.91, 125.78,
119.80, 118.31, 116.73, 115.94, 115.23, 11.59. Anal. Calcd. For C35H32N8O10S2: C, 53.29; H,
4.09; N, 14.21; S, 8.13; Found: C, 53.35; H, 4.13; N, 14.04; S, 8.20.
278- (C32H23Cl2CrN8O10S2)
Maroon/Yellowish Red, (66%) λmax (nm):464. FTIR (KBr, cm-1
) νmax: 3050 (C=C-H str.), 1642
(C=O str.), 1583, 1537 (C=C aromatic, C=N), 1485 (N=N str.), 1417, 1335 (SO3H str., CH2
bend.), 1226, 1145 (C-C, C-O str.), 1012 (S=O str.), 830 (Ar-H), 785(C-Cl str.). Anal. Calcd. For
C16H13ClN4O5S: C, 44.35; H, 2.68; N, 12.93; S, 7.40; Found: C, 44.43; H, 2.58; N, 12.83; S,
7.50.
279-C16H17ClFeN4O8S (7a)
3440 (OH str.), 3287 (NH str.), 3050 (C=C-H str.), 2924 (CH2 str.), 1653 (C=O str.), 1597, 1545
(C=C aromatic), 1466 (N=N str.), 1300 (N=O str.), 1418, 1334 (CH2str.), 1166 (C-O str.), 1004
73
(S=O), 833 (Ar-H) ,739 (C-Cl str.). Anal. Calcd. For C16H17ClFeN4O8S: C, 37.19; H, 3.32; N,
10.84; S, 6.20; Found: C, 37.13; H, 3.26; N, 10.70; S, 6.25.
280-C16H17ClCuN4O8S (7b)
3418 (OH str.), 3298 (NH str.), 3050 (C=C-H str.), 2928 (CH2 str.), 1653 (C=O str.), 1598, 1541
(C=C aromatic), 1466 (N=N str.), 1343 (CH2str.), 1172, 1125 (C-O str.), 812 (Ar-H),739 (C-Cl
str.). Anal. Calcd. For C16H17ClCuN4O8S: C, 36.65; H, 3.27; N, 10.68; S, 6.11; Found: C, 36.63;
H, 3.22; N, 10.60; S, 6.18.
282-(C32H23CrN10O14S2)
Reddish orange, (73%). λmax (nm):483. FTIR (KBr, cm-1
) νmax: 1676 (C=C str.), 1587 (C=C
aromatic, C=C), 1495, 1471 (N=N, NO2str.), 1267, 1172 (C-O str.), 1039 (C-OC str.), 829 (Ar-
H). Anal. Calcd. For C16H13N5O7S: C, 43.30; H, 2.61; N, 15.78; S, 7.22. Found: C, 43.20; H,
2.70; N, 15.89; S, 7.34.
283-C16H17FeN5O10S (7c)
3399 (NH str.), 3050 (C=C-H str.), 2926 (CH2 str.), 1550 (C=C aromatic), 1472 (N=N, NO2 str.),
1272, 1164 (C-O str.), 1004 (S=O), 834 (Ar-H). Anal. Calcd. For C16H17FeN5O10S C, 36.45; H,
3.25; N, 13.28; S, 6.08; Found: C, 36.48; H, 3.21; N, 13.19; S, 6.16.
284-C16H17CuN5O10S (7d)
3524 (OH str.), 3298 (NH str.), 3050 (C=C-H str.), 2924 (CH2 str.), 1619, 1584 (C=C aromatic,
C=N), 1474 (N=N), 1321 (NO2 bend.), 1284 (C-H bend.), 1123(C-O str.), 1004 (S=O), 840 (Ar-
H). Anal. Calcd. For C16H17CuN5O10S C, 35.92; H, 3.20; N, 13.09; S, 5.99; Found: C, 35.86; H,
3.14; N, 13.04; S, 6.10.
286- (C32H25CrN8O16S4)
Brown/Reddish orange, (74%). λmax (nm):489. FTIR (KBr, cm-1
) νmax: 3076 (C=C-H str.), 1623
(N-H bend.), 1621, 1599 (C=C aromatic), 1539 (N=N str.), 1498 (N-Hbend.), 1354 (SO3H, CH2
str.), 1174 (C-O str.), 814 (Ar-H). Anal. Calcd. For C16H14N4O8S2: C, 40.13; H, 2.63; N, 11.70;
S, 13.39; Found: C, 40.33; H, 2.54; N, 11.73; S, 13.41.
74
287-C16H18FeN4O11S2 (7e)
3383(NH str.), 3050 (C=C-H str.), 1638, 1568 (C=C str.), 1548 (NH bend.), 1474 (N=N str.),
1429 (CH bend), 1343 (CH2str.), 1276, 1162 (C-O str.), 1004 (S=O), 833 (Ar-H). Anal. Calcd.
For C16H18FeN4O11S2 C, 34.18; H, 3.23; N, 9.96; S, 11.40; Found: C, 34.14; H, 3.16; N, 9.86; S,
11.49.
288-C16H18CuN4O11S2 (7f)
3418 (OH), 1597 (C=C aromatic, C=N str.), 1528, 1474 (N=N str.), 1343 (CH2str.), 1272, 1209,
1174 (C-O str.), 1183(C-O str.), 1008 (S=O), 831(Ar-H). Anal. Calcd. For C16H18CuN4O11S2 :
C, 33.71; H, 3.18; N, 9.83; S, 11.25; Found: C, 33.75; H, 3.16; N, 9.77; S, 11.31.
290- (C32H23CrN10O20S4)
Brown/Reddish orange, (81%). λmax (nm):505. FTIR (KBr, cm-1
) νmax: 3056 (C=C-H str.), 1648
(C=C str. NH bend), 1622, 1539 (C=C aromatic), 1492 (N=N str.), 1343 (SO3H.), 1173 (C-O
str.), 1010 (S=O), 856 (Ar-H). Anal. Calcd. C32H23CrN10O20S4 C, 36.68; H, 2.21; N, 13.37; S,
12.24; Found: C, 36.73; H, 2.27; N, 13.39; S, 12.20.
291-C16H17FeN5O13S2 (7g)
3478 (OH str.), 3198 (NH str.), 3050 (C=C-H str.), 2928 (CH2 str.), 1619, 1586 (C=C aromatic,
C=N), 1541, 1436 (N=N str.), 1300 (N=O str.), 1343 (CH2str.), 1159(C-O str.), 1002(S=O), 833
(Ar-H). Anal. Calcd. For C16H17FeN5O13S2: C, 31.64; H, 2.82; N, 11.53; S, 10.56; Found: C,
31.60; H, 2.76; N, 11.44; S, 10.58.
292-C16H17CuN5O13S2 (7h)
3444 (OH), 3050 (C=C-H str.), 1600, 1559(C=C aromatic), 1489 (N=N str.), 1343 (CH2str.),
1179 (C-O str.), 1006 (S=O), 838 (Ar-H). Anal. Calcd. For C16H17CuN5O13S2: C, 31.25; H,
2.79; N, 11.39; S, 10.43; Found: C, 31.29; H, 2.74; N, 11.31; S, 10.50.
298 (C64H46Cr2N16O24S6)
Beige/Yellowish orange, (70%). λmax (nm):584. FTIR (KBr, cm-1
) νmax: 3048 (C=C-H str.), 1621,
1574 (C=C aromatic, C=N), 1496 (N=N str.), 1122 (C-O str.), 1011 (S=O), 869 (Ar-H). Anal.
75
Calcd. For C32H26N8O12S3:C, 47.48; H, 3.27; N, 13.86; S, 11.85; Found: C, 47.44; H, 3.33; N,
13.52; S, 11.81.
299-C32H34Fe2N8O18S3 (7i)
3184 (OH), 3050 (C=C-H str.), 2924 (CH2 str.), 1619, 1586 (C=C aromatic, C=N), 1498 (N=N
str.), 1006 (S=O), 829 (Ar-H). Anal. Calcd. For C32H34Fe2N8O18S3: C, 37.44; H, 3.34; N, 10.92;
S, 9.37; Found: C, 37.42; H, 3.30; N, 10.85; S, 9.42.
300-C32H34Cu2N8O18S3 (7j)
3352(OH str.), 3298 (NH str.), 3050 (C=C-H str.), 1559 (C=C aromatic, C=N), 1541 (N=N str.),
1205, 1103 (C-C str.), 997 (S=O), 836 (Ar-H). Anal. Calcd. For C32H34Cu2N8O18S3 : C, 36.89;
H, 3.29; N, 10.75; S, 9.23; Found: C, 36.85; H, 3.33; N, 10.66; S, 9.18.
302- (C70H58Cr2N16O20S4)
Tan/Reddish orange, (73%). λmax (nm):479. FTIR (KBr, cm-1
) νmax: 1645, 1589 (C=C aromatic),
1485(N=N str.), 1341 (SO3H str.), 1210, 1150, 1118 (C-C str.), 999 (S=O), 875 (Ar-H). Anal.
Calcd. For C35H32N8O10S2: C, 45.81; H, 3.02; N, 18.53; S, 12.34. Found: C, 45.85; H, 3.09; N,
18.56; S, 12.38.
303-C35H40Fe2N8O16S2 (7k)
3440 (OH str.), 3220 (NH str.), 2967 (C=C-H str, CH2 str.), 1675(C=Ostr.), 1653, 1593(C=C
aromatic), 1541, 1507 (N=N str.), 1340 (CH2), 1161 (C-O str.), 1004 (S=O), 829 (Ar-H). Anal.
Calcd. For C35H40Fe2N8O16S2: C, 41.85; H, 4.01; N, 11.15; S, 6.38; Found: C, 41.81; H, 4.00;
11.10; S, 6.44.
304-C35H40Fe2N8O16S2 (7l)
3440 (OH str.), 3231 (NH str.), 3050 (C=C-H str.), 2967 (CH2 str.), 1653 (C=Ostr.), 1541 (C=C
aromatic), 1498 (N=N str.), 1364, 1340 (SO3Hstr.), 1161 (C-O str.), 1004 (S=O), 829 (Ar-H).
Anal. Calcd. For C35H40Cu2N8O16S2 : C, 41.22; H, 3.95; N, 10.99; S, 6.29; Found: C, 41.19; H,
3.90; N, 10.92; S, 6.34.
76
Chapter 4 RESULTS AND DISCUSSION
4.1 Synthesis of 4-amino-1-(p-sulphophenyl)-3-methyl-5-pyrazolone and its diazonium Salt
Synthesis of diazonium salt of SPMP was achieved according to Scheme 4.1, which involve
nitrosation, reduction and diazotization in a stepwise manner as shown below.
NN
CH3
OH
SO3
- Na
+
NaNo2,HCl
-5 - 0 oC
NN
CH3
O
SO3
- Na
+
N OH
NN
CH3
O
SO3
- Na
+
NH3Cl-
NN
CH3
O-
SO3
- Na
+
N+
N
Zn + HCl
100 - 105 oC
NaNo2,HCl
-5 - 0 oC
(144) (145) (146) (147)
+
Scheme 4.1; Synthesis of 4-amino-1(p-sulphophenyl)-3-methyl-5-pyrazolone and its diazonium
salt.
4.2 Nitrosation, Reduction and Diazotization of SPMP
The initial step of the reaction series was nitrosation of SPMP [1(4-sulphohenyl)-3-methyl-5-
pyrazolone] (144). 1(4-sulphophenyl) 3-methyl-2-pyrazolin-5-one (SPMP) was nitrosated at 0-
5ºC using NaNO2 and HCl as described by Knorr1. The nitroso compound was filtered to remove
some terry material. The clarified nitroso derivative that usually exists in an oxime form (as
indicated by its FTIR), was salted out by common salt and dried after filtration. Reduction of
Nitrso/Oxime of SPMP was carried at 100-105ºC using Zinc and HCl. The oxime of SPMP and
zinc metal were added in small portions at boil. The reduction was completed as the solution
became colorless. A small amount of additional zinc was added and the resultant amine
hydrochloride was quenched to -7 ºC. The excessive un-reacted zinc was removed by filtration.
The amine hydrochloride of SPMP was diazotized using an aqueous solution of NaNO2 (6.9g
dissolved in 250mL of solution) and HCl at -5 to -2ºC to avoid the formation of rubazoic acid,
which is automatically formed during this reaction with increasing temperature due to oxidizing
action of nitrous acid formed in situ.
In the crystal structure of diazonium salt the phenyl as well as the pyrazolone-ring lie almost in
plane, the relevant torsion angle C1-N1-C5-C6 measures 3.3(5)°. Essential bonding parameters
of the pyrazolone moiety are N1-N2 1.407(3), C1-O1 1.230(3), C2-N3 1.325(4), N3-N4 1.110(3)
77
Å, and C2-N3-N4 177.3(3)°. These are in close agreement with those of 4-Diazonio-2-methyl-5-
nitro-3-oxo-2,3-dihydropyrazol-1-ide (WETGEJ)x1
with N-N 1.362, C-N2 1.323, (C)N-N 1.116
Å and C-N-N 177.7°. The crystal structure (Figure 2) shows various hydrogen bonding pattern
with the solvent water molecules. Strongest interactions are O10-H11…O11(-x+1, -y+1, -z+2)
with H…O of 1.939 Å, O20-H21…O12(x, y+1, z) with 1.979 Å, O10-H12…O12(x-1, y+1, z)
with 2.005 Å and O20-H22…N2 with 2.139 Å. An intramolecular C6-H…O1 bond is connected
with the planar arrangement of both the aromatic ring planes. The molecular structure of
diazonium salt is depicted in Figure 4.1; the unit cell with intermolecular H-bonding pattern is
shown in Figure 4.2.
Figure 4.1; ORTEP diagram of SPMP diazonium Salt.
78
Figure 4.2. Crystal packing with hydrogen bonding pattern as dotted lines.
The parent compound exists mainly as an enol form as indicated by its FTIR spectra (Figure-
4.3) (enolic OH = 3166cm-1
,C=C =1591cm-1
,S=O =1183cm-1
).while the nitroso derivative
existed in the form of a keto-oxime as indicated by it FTIR spectra (Figure-4.4) (appearance of a
C=O at 1716cm-1
,C=N at 1595cm-1
,S=O at 1194cm-1
). The oxime was in turn reduced to an
amine which was difficult to be isolated, hence the crude reaction product was diazotized to get
its diazonium salt which existed as an internal salt as indicated by its FTIR (Figure-4.5) (HOH
=3416cm-1
, N+
NAr-
at 2124cm-1
, C=C at 1595cm-1
,S=O at 1354cm-1
). The diazonium
oxide was isolated by salting out at 30% per volume and at 0-3oC after cooling for 18-20 hours.
The filtered diazonium compound (167) was yellow in color. It was dried in vacuum dessicator
at 25-30oC to get it in dry form for coupling with desired couplers. The yield of diazonium
compound was about 95% as found by its coupling with β-naphthol. The diazonium compound
was crystallized from ethanol and subjected to X-ray analysis. The physical data obtained from
X-ray analysis is presented in Tables 4.1 and 4.2.
79
Table-4.1; X-Ray Crystallographic data of SPMP diazonium Salt
Crystal data
Chemical formula C10H12N4NaO6S
Mr 339.29
Temperature (K) 296
a, b, c (Å) 7.3243 (5), 9.8930 (7), 10.5934 (8)
102.563 (4), 105.564 (4), 92.096 (4)
V (Å3) 718.05 (9)
Z 2
Radiation type Mo K
-1) 0.29
Crystal size (mm) 0.36 × 0.28 × 0.24
Absorption correction –
No. of measured, independent and
observed [I I)] reflections 10943, 3135, 2480
Rint 0.028
max (Å-1
) 0.640
Refinement
R[F2 F
2)], wR(F
2), S 0.036, 0.096, 1.04
No. of reflections 3135
No. of parameters 212
H-atom treatment H atoms treated by a mixture of independent
and constrained refinement
max min (e Å-3
) 0.28, -0.34
80
Table-4.2; Selected geometric parameters (Ao) of 1-(p-sulphophenyl)-3-methyl-4-azo-5-
pyrazolone
Na—O1i 2.2763 (15) N1—C6 1.417 (2)
Na—O5 2.2907 (17) N2—C9 1.303 (2)
Na—O6 2.3630 (16) N3—N4 1.109 (2)
Na—O4 2.3733 (15) N3—C8 1.328 (2)
Na—O6ii 2.4951 (16) C1—C2 1.382 (3)
Na—S1 3.3338 (9) C1—C6 1.387 (3)
Na—Naii 3.6887 (14) C1—H1 0.9300
S1—O2 1.4387 (16) C2—C3 1.380 (3)
S1—O4 1.4439 (14) C2—H2 0.9300
S1—O3 1.4543 (16) C3—C4 1.385 (3)
S1—C3 1.7720 (18) C4—C5 1.383 (3)
O1—C7 1.225 (2) C4—H4 0.9300
O1—Naiii
2.2763 (15) C5—C6 1.386 (2)
O5—H1 0.79 (3) C5—H5 0.9300
O5—H2 0.75 (3) C7—C8 1.433 (2)
O6—Naii 2.4951 (16) C8—C9 1.413 (3)
O6—H3 0.80 (3) C9—C10 1.488 (3)
O6—H4 0.84 (3) C10—H10A 0.9600
N1—C7 1.385 (2) C10—H10B 0.9600
N1—N2 1.405 (2) C10—H10C 0.9600
Symmetry code(s): (i) x-1, y, z-1; (ii) -x-1, -y+1, -z; (iii) x+1, y, z+1.
81
The above X-ray data revealed that it was a diazoxide sodium salt with two water molecules as
presented in its X-ray ORTEP diagram.
Note: Although the diazonium salts are generally unstable and often, at higher temperatures
decompose violently, however the present salt was very stable up to 750C and could be
recrystallized without explosion or decomposition. This could be kept in dry crystalline form for
several months without losing its stability.
Figure 4.3; FTIR spectrum of 1(p-sulphophenyl)-3-methyl-5-pyrazolone
Figure 4.4; FTIR spectrum of oxime of 1(p-sulphophenyl)-3-methyl-5-pyrazolone.
82
Figure 4.5; FTIR spectrum of diazo-1(p-sulphophenyl)-3-methyl-5-pyrazolone
4.3 Synthesis of Naphthol-AS Series of Dyes
In this series a total number of 28 dye samples were prepared with 7 different naphthols namely
naphthol-ASA, naphthol-AS BS, naphthol-AS D, naphthol-AS E, naphthol-AS LC, naphthol-
ASOL and naphthol-ASPH were used as couplers. Four dye samples were prepared with each
coupler. The first being an un-metalized dye and the three being chromium, iron and copper
complexes respectively. Chromium complexes were 2:1 type. For chromium dyes all three of the
water molecules being replaced by another molecule of the same dye to form a 2:1 complex.
It is note worthy to mention here that UV-Visible Spectra are screen prints of Spectra-flash
SF-550.The un-metalized dyes were used as standards and are shown as RED Spectrum. The
overall synthesis of these dyes is given in the Scheme-4.2.
83
NN
CH3
OH
SO3
- Na
+
NaNo2,HCl
-5 - 0 oC
NN
CH3
O
SO3
- Na
+
N OH
NN
CH3
O
SO3
- Na
+
NH3Cl-
NN
CH3
O-
SO3
- Na
+
N+
N
Zn + HCl
100 - 105 oC
NaNo2,HCl
-5 - 0 oC
(144) (145) (146) (147)
+
NN
CH3
O-
SO3
- Na
+
N+
N
Diazo
+
O
NHOH R1
R2
R3R4
Naphthol-AS Couplers(2a-g)
Na2CO3/NaOHN
N
CH3
OH
SO3H
N
N
O
NHOH R1
R2
R3R4
Dyes = 3a-g
N
N
CH3
O
N
N
O
NHO R1
R2
R3R4
HO3S
N
N
CH3
O
N
N
O
NH OR1
R2
R3 R4
SO3HCr
-
OH2OH2
OH2
N
N
CH3
O
N
N
O
NHO R1
R2
R3R4
M
HO3S
65 -75 oCCr(CH3COO-)3
100 - 105 oC
2a R1 =R2= R3 =R4=H
2c R2= R3 =R4=H,R4=CH3
2b R1 = R3 =R4=H,R2=NO2
2d R1= R2 =R4=H,R3=Cl
2e R1= R4 = OCH3,R2=H,R3=Cl
2f R1= OCH3,R2=R3,R4=H
2g R1= OC2H5,R2=R3,R4=H
3a-g Dyes = 201,205,209,213,217,221,225
5a-g Dyes = 203,207,211,215,219,223,227
6a-g Dyes = 204,208,212,216,220,224,228
7a-g Dyes = 202,206,210,214,218,222,226
7a-g Dyes
5a-g,6a-g Dyes
Metal Salts 4a-b
4a= FeSO4 .7H2O
4b= CuSO4 .5H2O
Scheme 4.2, Synthesis of acid dyes 3a-g and their Fe (II, 5a-g), Cu (II, 6a-g) and Cr (III, 7a-g)
complexes (201-228).
The synthesis of acid dyes 3a-g (201, 205, 209, 213, 217, 221, 225), based on 1-(p-
sulphophenyl)-3-methyl-5- pyrazolone and their iron (II), copper (II) and chromium (III)
complexes (5a-g, 6a-g and 7a-g) was achieved by following a four step procedure involving
synthesis of 1-(p-sulphophenyl)-3-methyl-4-amino-5- pyrazolone, diazotization, coupling with
different naphthol AS series couplers (2a-g) and their metal complex formation according to
84
scheme 4.2. The rational for selection of these dyes for synthesis, is to acquire various scaffolds
of this nature by metallization and to observe their shade and dyeing properties on leather.
Synthesis of this diazo intermediate has been confirmed from X-ray structure of its crystal
(Figure 4.1). Coupling was made in alkaline medium to do the reaction at ortho position to the
hydroxyl group of naphthol AS series and was accomplished in 2.5h with continuous stirring.
Synthesized dyes 3a-g (201, 205, 209, 213, 217, 221, 225) were precipitated on completion of
reaction by changing the pH of solution to acidic at 4.0 with HCl. Dyes were dried and purified
in ethanol. Metallization of above synthesized dyes was done by treating the alkaline solution of
dyes with FeSO4.7H2O, CuSO4.5H2O and Cr (CH3COO-)3 with continuous stirring and heating
the reaction mixture at 55-70oC for 4-5 h until the confirmation about completion of reaction was
observed by taking the TLC of reaction mixture in 9:1 chloroform and methanol. Dyes (3a-g)
were precipitated with addition of HCl, filtered and dried in oven at 80 oC. Dyes were again
purified from ethanol, dried, weighed and determined the percentage yield. Dyes 3a-g were
further processed for metallization. These unmetallized dyes 3a-g were tridentate ligands which
formed complexes with Iron (Fe, II) and Copper (Cu, II) through 1:1 metal and ligand
stoichiometric ratio and Chromium (Cr, III) formed complexes by 2:1 fashion. In case of Fe2+
and Cu2+
complexes lone pairs of electrons are donated by two oxygen atoms and one nitrogen
atom of the diazo linkage, while the other three coordination numbers of these metals have been
satisfied by three water molecules. The chromium complexes were octahedral and six
coordination number of Cr3+
was fulfilled by two ligand molecules. The complex formation
pattern has been verified by the UV. Visible Spectrophotometric studies of complex formation of
3a-g (201, 205, 209, 213, 217, 221, and 225) dyes.
4.3.1 Naphthol-ASA dyes
Four dye samples were prepared with naphthol-AS. The first being an un-metalized dye and the
three were chromium, iron and copper complexes respectively. Chromium complex was a 2:1
type. The detailed properties are shown in Table-4.3
85
Table-4.3 Physical properties of dyes 201-204
The UV-Visible data presented in table 4.3 are supported by UV-Visible Spectra-1 (Figure
4.6).The un-metallized dye (3a) 201 was a reddish orange dye with λmax 510 nm and absorbance
3.3.Its metallization with chromium had changed its λmax to 520 nm and absorbance 2.8 (dye
202), showing a bathochromic shift of 10 nm with a hypochromic effect of 0.5.
On the other hand metallization of dye 201 with iron produced a yellowish brown dye (dye 203)
with λmax 480 nm and absorbance 3.6, showing a hypsochromic shift of 30 nm with a
hyperchromic effect of 0.3.While metallization of dye (3a) 201 with copper resulted in the
formation of a reddish violet dye (dye 204) with λmax 520 nm and absorbance 3.5, showing a
bathoochromic shift of 10 nm with a hyperchromic effect of 0.2.
Dye # Dye Structure Molecular
formula
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
201 HO3S
N
N
CH3
OH
N N
OH
O
NH
C27H21N5
O6S
Orange/
Reddish
Orange
510/3.3 Ethanol
202
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
H+
C54H39Cr
N10 O12S2
Pink/
Violet 520/2.8 Ethanol
203
OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe
C27H25Fe
N5O9S
Brown/
Yellowish
Brown
480/3.6 Ethanol
204
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu
C27H21Cu
N5O7S
Tan/
Reddish
Violet
520/3.5 Ethanol
86
Figure 4.6; UV-Visible Spectra-1 of dyes 201-204 (4851-umd = dye 201,
4851-Cr = dye 202, 4851-Fe = dye 203 and 4851-Cu = dye 204)
4.3.2 Naphthol-ASBS dyes.
Four dye samples were prepared with naphthol-ASBS. The first being an un-metalized dye and
the three were chromium, iron and copper complexes respectively. Chromium complex was a 2:1
type.The detailed properties are shown in Table-4.4
87
Table-4.4 Physical properties of dyes 205-208
The UV-Visible data presented in Table-4.4 is supported by UV-Visible Spectra-2 (Figure 4.7).
The un-metallized dye 205 (3b) was a reddish orange dye with λmax 510 nm and absorbance
2.8.Its metallization with chromium produced a Bordeaux dye. It had changed its λmax to 520 nm
and absorbance 1.65 (dye 206), showing a bathochromic shift of 10 nm with a hypochromic
effect of 0.53.
On the other hand metallization of dye 205 (3b) with iron also produced a Bordeaux dye (dye
207) with λmax 500 nm and absorbance 1.66, showing a hypsochromic shift of 20 nm with a
hyperchromic effect of 0.52.
While metallization of dye 205 (3b) with copper resulted in the formation of a reddish orange
dye (dye 208) with λmax 510nm and absorbance 2.1, showing a hypsochromic shift of 20 nm with
a hyperchromic effect of 0.7.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
205 HO3S
N
N
CH3
OH
N N
OH
O
NH
O2N
C27H20N6
O8S
Brown/
Reddish
Orange
510/2.18 Ethanol
206 H+
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
NO2
NO2
C54H36Cr
N12 O16S2
Violet
Brown/
Bordeaux
520/1.65 Ethanol
207
OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe
O2N
C27H24Fe
N6 O11S
Dark
Brown/
Bordeaux
500/1.66 Ethanol
208
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu
O2N
C27H20Cu
N6 O9S
Violet/
Reddish
Orange
510/2.1 Ethanol
88
Figure 4.7; UV-Visible Spectra-2 of dyes 205-208 (4899-umd = dye 205,
4899-Cr = dye 206, 4899-Fe = dye 207 and 4899-Cu = dye 208)
4.3.3 Naphthol-ASD Dyes.
Four dye samples were prepared with naphthol-ASD. The first being an un-metalized dye and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was a 2:1 type. The detailed properties are shown in Table-4.5
89
Table-4.5; Physical properties of dyes 209-212
The UV-Visible data presented in Table-4.5 is supported by UV-Visible Spectra-3 (Figure
4.8).The un-metallized dye 209 (3c) was an orange dye with λmax 510 nm and absorbance 2.1. Its
metallization with chromium changed its λmax to 520 nm (a pink dye) with absorbance 1.5 (dye
210), showing a bathochromic shift of 10 nm with hypochromic effect of 0.6.
On the other hand metallization of dye 209 (3c) with iron produced an olive brown dye (dye 211)
with λmax 510 nm and absorbance 1.1, showing a hypsochromic shift of 10nm with a
hypochromic effect of 1.0.While metallization of dye 209 (3c) with copper resulted in the
formation of a reddish orange dye (dye 212) with λmax 510 nm and absorbance 1.5, with no
change of color but a hyperchromic effect of 0.6.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
209 HO3S
N
N
CH3
OH
N N
OH
O
NH CH3
C28H23N5O6S
Tan/
Reddish
Orange
400/1.1,
510/2.1 Ethanol
210 H+
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
CH3
CH3
C56H42Cr
N10O12S2
Violet/
Pink
400/0.9
520/1.5 Ethanol
211
OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe CH3
C28H27Fe
N5 O9S
Dark
Brown/
Olive
Brown
400/0.8
510/1.1 Ethanol
212
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu CH3
C28H23Cu
N5O7S
Violet/
Reddish
Orange
400/0.9
510/1.5 Ethanol
90
Figure 4.8; UV-Visible Spectra-3 of dyes 209-212 (4852-umd = dye 209,
4852-Cr = dye 210, 4852-Fe = dye 211 and 4852-Cu = dye 212)
4.3.4 Naphthol-ASE Dyes.
Four dye samples were prepared with naphthol-ASE. The first being an un-metallized dye and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was a 2:1 type. The detailed properties are shown in Table-4.6
91
Table-4.6 Physical properties of dyes 213-216
The UV-Visible data presented in Table-4.6 are supported by UV-Visible Spectra-4 (Figure
4.9).The un-metalized dye 213 (3d) was an orange dye with λmax 510 nm and absorbance 2.8. Its
metallization with chromium had changed its λmax to 520 nm and absorbance 1.8 (dye 214),
showing a bathochromic shift of 10 nm with a hypochromic effect of 1.0. On the other hand
metallization of dye 213 with iron produced a yellowish brown dye (dye 215) with λmax 480 nm
and absorbance 1.8, showing a hypsochromic shift of 30 nm with a hypochromic effect of 1.3.
While metallization of dye 213 (3d) with copper resulted in the formation of a Bordeaux dye
(dye 216) with λmax 510 nm and absorbance 1.5, showing no change of color but a hyperchromic
effect of 1.3.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
213 HO3S
N
N
CH3
OH
N N
OH
O
NH
Cl
C27H20Cl
N5O6S
Tan/
Reddish
Orange
400/1.05,
510/2.8 Ethanol
214
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
Cl
Cl
H+
C54H36Cl2Cr
N10O12S2
Dark
Brown/
Bordeaux
400/0.9,
520/1.8 Ethanol
215 OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe
Cl
C27H24ClFe
N5O9S
Brown/
Yellowish
Brown
480/1.8 Ethanol
216
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu
Cl
C27H20ClCu
N5O7S
Dark
Brown/
Bordeaux
400/0.8
510/1.5 Ethanol
92
Figure 4.9; UV-Visible Spectra-4 of dyes 213-216 (4812-umd = dye 213,
4812-Cr = dye 214, 4812-Fe = dye 215 and 4812-Cu = dye 216)
4.3.5 Naphthol-ASLC Dyes
Four dye samples were prepared with naphthol-ASLC. The un-metallized dye 217 (3e) was
metallized with chromium (III), iron (II) and copper (II) respectively. Chromium complex was a
2:1 type. The Physicochemical properties are shown in Table-4.7.
93
Table-4.7 Physical properties of dyes 217-220
Table-4.7 presents the λmax and absorbance of dyes 217-220 that is supported by UV-Visible
Spectra-5 (Figure 4.10). The un-metallized dye 217 (3e) was a reddish orange dye with λmax 500
nm and absorbance 1.3.Its metallization with chromium had changed its color to violet with λmax
520 nm and absorbance 0.8 (dye 218), showing a bathochromic shift of 20 nm with a
hyperchromic effect of 0.5.On the other hand metallization of dye 217 (3e) with iron produced a
yellowish brown dye (dye 219) with λmax 500 nm and absorbance 1.4, showing a hyperchromic
effect of 0.1 with almost no change in color.While metallization of dye 217 (3e) with copper
resulted in the formation of a reddish orange dye (dye 220) with λmax 520 nm and absorbance 1.0
, showing a bathochromic shift of 20 nm with a hypochromic effect of 0.3.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax
(nm)/
Absorba-
nce
Solubility
217 HO3S
N
N
CH3
OH
N N
OH
O
NH
Cl
OCH3
H3CO
C29H24Cl
N5O8S
Orange/
Reddish
Orange
360/1.3,
500/1.3 Ethanol
218 H+
Cl
Cl
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
OCH3
H3CO
OCH3
H3CO
C58H45Cl2
CrN10O16S2
Light
Pink/
Violet
360/1.0,5
20/0.8 Ethanol
219 OH2
OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NH
Cl
OCH3
H3CO
Fe
C29H28ClFe
N5O11S
Brown/
Yellowish
Brown
360/1.85
00/1.4 Ethanol
220
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu
ClH3CO
OCH3
C29H24Cl
CuN5O9S
Tan/
Reddish
Orange
360/1.05
20/1.0 Ethanol
94
Figure 4.10; UV-Visible Spectra-5 of dyes 217-220 (4813-umd = dye 217,
4813-Cr = dye 218, 4813-Fe = dye 219 and 4813- Cu = dye 220)
4.3.6 Naphthol-ASOL Dyes.
Four dye samples were prepared with naphthol-ASOL. The first being an un-metalized dye and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was a 2:1 type. The detailed properties are shown in Table-4.8
95
Table-4.8 Physical properties of dyes 221-224
UV-Visible data presented in Table-4.8 are supported by UV-Visible Spectra-6 (Figure 4.11).
The un-metallized dye 221 (3f) was an orange dye with λmax510 nm and absorbance 2.1. Its
metallization with chromium had changed its color to maroon with λmax520 nm and absorbance
1.6 (dye 222), showing a bathochromic shift of 10 nm with a hypochromic effect of 0.5.On the
other hand metallization of dye 121 with iron produced a Bordeaux dye (dye 223) with λmax500
nm and absorbance 1.6, showing a hypsochromic shift of 10 nm with a hyperchromic effect of
0.5.While metallization of dye 221 with copper resulted in the formation of a maroon dye(dye
224) with λmax510 nm and absorbance 0.9, with a hypsochromic effect of 0.2.
Dye# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λ max (nm)/
Absorbance Solubility
221 HO3S
N
N
CH3
OH
N N
OH
O
NH OCH3
C28H23N5
O7S
Orange/
Reddish
Orange
400/1.1
510/2.1 Ethanol
222 H+
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
OCH3
OCH3
C56H43Cr
N10O14S2
Dark
Brown/
Maroon
400/0.9
520/1.6 Ethanol
223
OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe OCH3
C28H27Fe
N5O10S
Brown/
Bordeaux 500/1.6 Ethanol
224
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu OCH3
C28H23Cu
N5O8S
Tan/
Maroon 510/0.9 Ethanol
96
Figure 4.11; UV-Visible Spectra-6 of dyes 221-224 (48OL-umd = dye 221,
48OL-Cr = dye 222, 48OL-Fe = dye 223 and 48OL- Cu = dye 224)
4.3.7 Naphthol-ASPH dyes.
Four dye samples were prepared with naphthol-ASPH. The first being an un-metallized dye and
other dyes were chromium, iron and copper complexes respectively. Chromium complex was a
2:1 type. The detailed properties are shown in Table-4.9
97
Table-4.9 Phsical properties of dyes 225-228
The UV-Visible data presented in Table-4.9 are supported by UV-Visible Spectra-7 (Figure
4.12). The un-metallized dye 225 (3g) was an scarlet dye with λmax510 nm and absorbance
2.2.Its metallization with chromium had not changed its color ( λmax510 nm) but absorbance 1.9
(dye 226), showing a hypochromic effect of 0.2.On the other hand metallization of dye 225 (3g)
with iron produced an olive brown dye (dye 227) with λmax 490 nm and absorbance 1.8, showing
a hypsochromic shift of 20 nm with a hypochromic effect of 0.4.While metallization of dye
225(3g) with copper resulted in the formation of a pink dye (dye 228) with λmax 510 nm and
absorbance 2.0, with a minor change being a hypochromic effect of 0.20.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorb-
ance
Solubility
225 HO3S
N
N
CH3
OH
N N
OH
O
NH OC2H5
C29H25N5
O7S
Bordeaux/
Scarlet 510/2.2 Ethanol
226 H+
HO3S
N
N
CH3
O
N N
O O
NH
HO3S
N
N
CH3
O
N N
O O
NH
Cr-
OC2H5
OC2H5
C58H47Cr
N10O14S2
Dark
brown/
Scarlet
510/1.9 Ethanol
227
OH2 OH2OH2
HO3S
N
N
CH3
O
N N
O
O
NHFe OC2H5
C28H27Fe
N5O10S
Gray/
Olive
Brown
490/1.85 Ethanol
228
OH2
HO3S
N
N
CH3
O
N N
O
O
NHCu OC2H5
C29H25Cu
N5O8S
Dark
Brown/
Pink
510/2.0 Ethanol
98
Figure 4.12; UV-Visible Spectra-7 of dyes 225-228 (4898-umd = dye 225,
4898-Cr = dye 226, 4898-Fe = dye 227 and 4898- Cu = dye 228).
4.4 Spectral properties of naphthol-AS dyes
The infrared spectra of the synthesized acid dyes and their metal complexes exhibited absorption
peaks due to O-H,N-H, Ar-H, C-H, C=O, C=C, N=N, SO3H, C-O and O-M stretching and
bending vibrations at 3292-3315, 3045-3065, 2920-2931, 1675-1685, 1620-1660, 1526-1590,
99
1440-1455, 1160-1215, 1050-1130, 840-885 and 540-560 cm-1
as depicted from their FTIR
spectra. Specifically speaking, using FTIR spectrum of dyes 3a-g, a broad band is observed in
the range 2500-3500 cm-1
which is due to H-bonding of OH and N-H groups in close proximity
to each other in couplers which are masking the N-H peaks in some cases while in other cases
small single peak is present which shows that 2o amine group is present. Aromatic benzene and
naphthalene rings are evidenced by presence of peaks in the range 3045-3065 cm-1
due to C-H
stretching of unsaturated carbon atoms which are further confirmed by their peaks at 1620-1660
and 1526-1590 cm-1
. A peak is observed in the range 1675-1685 cm-1
which is due to amide
carbonyl functionality of dyes. The absorption bands at 1428-1455 cm-1
depicted the presence of
N=N stretching vibrations of dyes and this peak is common in all dyes. Synthesis of dyes 3a-g
has been confirmed by their FTIR spectra. The metal complexes of dyes 3a-g (201, 205, 209,
213, 217, 221, 225) have been inveterated by the presence of peaks at low frequency region at
525-540, 580-590 and 618-630 cm-1
because of large masses of metal atoms and these peaks are
absent in their respective FTIR spectra.
The 1H-NMR spectra of all dyes 3a-g (201, 205, 209, 213, 217, 221, 225) showed signals
down field at 9.82-12.03 ppm and 8.32-10.32 due to OH and N-H groups present in the coupling
components of dyes and were highly deshielded due to H-bonding. Similarly symmetrical
doublet peaks at 7.21-7.30 and 7.72 -7.80 ppm with same coupling constants were observed in
all dyes having benzene ring containing SO3H group. Methyl group singlet peak and methylenic
proton singlet was also common in all dyes and was present in the range 2.20-2.47 and 4.81-4.89
ppm (Figure 4.13). All these dyes 3a-g(201, 205, 209, 213, 217, 221, 225) were compounds of a
series where difference arises in case coupling component containing different substituents.
Naphthalene ring 4H multiplet peaks and 1H singlet peak at positions 7.82-7.75 and 7.38-7.45
ppm were common in all dyes. Difference in the H1-NMR spectrum of all dyes lies in the phenyl
group present at amide position of coupler. Multiplicity of these peaks is different in different
dyes. In case of C13
-NMR of all dyes showed the two carbonyl peaks at 165 and 169 ppm as
were present (Figure 4.14).
100
Figure 4.13, 1H-NMR Spectrum of Acid Dye 209 (3c)
101
Figure 4.14, 13
C-NMR Spectrum of Acid Dye 209 (3c)
4.5. DYEING PROPERTIES OF NAPHTHOL-AS DYES.
Dyeing properties of naphthol-AS dyes have been found to be very good. Almost all properties
have been found to be of very high values (4-5).However, chromium complexes were found to
be the best ones. The un-metallized dye-ligands owned low values as per expectations, due to the
presence of free hydroxyl groups. The results of the dyeing experiments are summarized in
table-4.10 which presents the dyeing properties of naphthol-AS series of dye. The applied dyes
samples on leather pieces are illustrated in Shade Card 1 part-a and part-b.
102
Table-4.10; Dyeing properties of naphthol-AS series
The data presented in Table-4.10 are supported by Shade card-1 part a-b.
Dye
#
2%Shade on
Leather
5%Shade on
Leather Penetration
Washing
Fastness
Light
Fastness
Perspiration
Fastness
201 Very Light Pink Light Pink 2 2-3 2-3 3-4
202 Light pink Pink 4 3-4 4-5 4-5
203 Light Beige Dark Beige 5 4-5 5 5
204 Light Pink Tea Pink 3 3-4 3-4 4-5
205 Light Orange Dark Orange 2 2-3 2-3 3-4
206 Reddish Violet Bordeaux 4 3-4 4-5 4-5
207 Yellowish Brown Dark Brown 5 4-5 5 5
208 Bluish Red Dark Bluish Red 3 3-4 3-4 4-5
209 Orange Reddish Orange 2 2-3 2-3 3-4
210 Bluish Red Bordeaux 4 3-4 4-5 4-5
211 Tan Dark Tan 5 4-5 5 5
212 Tea Pink Bluish Red 3 3-4 3-4 4-5
213 Reddish Beige Orange 2 2-3 2-3 3-4
214 Pink Bordeaux 4 3-4 4-5 4-5
215 Yellowish Brown Olive Brown 5 4-5 5 5
216 Light Pink Dark Pink 3 3-4 3-4 4-5
217 Light Beige Reddish Beige 2 2-3 2-3 3-4
218 Pink Dark Pink 4 3-4 4-5 4-5
219 Brown Dark Brown 5 4-5 5 5
220 Light Pink Dark Pink 3 3-4 3-4 4-5
221 Reddish Beige Dark Reddish Beige 2 2-3 2-3 3-4
222 Light Pink Dark Pink 4 3-4 4-5 4-5
223 Yellowish Beige Dark Yellowish
Beige 5 4-5 5 5
224 Light Pink Dark Pink 3 3-4 3-4 4-5
225 Beige Reddish beige 2 2-3 2-3 3-4
226 Reddish Violet Dark Violet 4 3-4 4-5 4-5
227 Yellowish Brown Reddish Brown 5 4-5 5 5
228 Light Pink Bluish Red 3 3-4 3-4 4-5
103
Shade Card 1 part-a
104
Shade Card 1 part b
A mutual comparison of shades of naphthol-AS series is presented in Shade Comparison 1-4 for
un-metallized, chromium, iron and copper complexes respectively.
105
Shade comparison-1
COMPARISON OF NAPHTHOL-AS BASED UN-METALLIZED DYES
Dye # Naphthol-AS 2% shade 5% shade
201 A
205 BS
209 D
213 E
217 LC
221 OL
225 PH
106
As it is clear from Shade comparison-1 (un-metallized), almost all of the dyes had similar
shades with a variation of only depth of shades. This may be attributed to the fact that the main
chromophoric system remained the same in all dyes. The variation of the depth can also be
attributed to the participation of peripheral group’s variation in naphthol-AS types.
Shade comparison-2
COMPARISON OF CHROMIUM METALLIZED NAPHTHOL-AS DYES
Dye # Naphthol-AS 2% Shade 5% Shade
202 A
206 BS
210 D
214 E
218 LC
222 OL
226 PH
107
As it is clear from Shade comparison-2 (chromium-metalized dyes) almost all of the dyes had
similar shades with a variation of only depth of the shades. This can be attributed to the fact that
the main chromophoric system remained the same in all un-metallized dyes. These dyes are very
bluish (Violet) than un-metallized parent dyes. However chromium complexes of naphthol-
ASBS, ASD, ASE, ASLC and ASPH were much darker in shades as compared to naphtol ASA
and ASOL. This variation of the depth can be attributed due to the participation of peripheral
group’s variation of difference of naphthol-AS moieties.
Shade comparison -3
COMPARISON OF IRON METALLIZED NAPHTHOL-AS DYES
As it is clear from Shade comparison-3 (iron-metallized dyes), almost all of the dyes had
different shades as compared with their parent dyes or chromium complexes.These were olive to
reddish brown in color with a variation of depth of shades. This can be attributed to the fact that
Dye # Naphtol-AS 2% Shade 5% Shade
203 A
207 BS
211 D
215 E
219 LC
223 OL
227 PH
108
the main chromophoric system remained the same in all iron-metallized dyes. However like
chromium, iron complexes of naphthol-ASBS, ASD, ASE, ASLC and ASPH were much darker
in shades as compared to naphthol-ASA and ASOL. This variation of the depth canbe attributed
to the participation of peripheral groups variation of naphthol-AS moieties.
Shade comparison -4
COMPARISON OF NAPHTHOL-AS COPPER COMPLEX DYES
Dye # Naphthol-AS 2% Shade 5% Shade
204 A
208 BS
212 D
216 E
220 LC
224 OL
228 PH
It is clear from Shade comparison-4 (copper-metallized dyes) almost all of the dyes had similar
shades with a variation of only depth of shades. This can be attributed to the fact that the main
chromophoric system remained the same in all copper-metallized dyes. These dyes are reddish
blue (violet) than un-metallized parent dyes. However copper complexes of naphthol-ASBS and
109
ASE are similar with deep shades, while that of ASLC and ASPH are lighter than these and
comparable in shades. In the same way shades of naphthol-ASA and ASOL are very similar to
parent dye ligands except a much bluish tone. This variation of the depth can be attributed to the
dye ligands by the participation of peripheral group’s variation of different of naphthol-AS types.
4.6 SYNTHESIS OF PYRAZOLONE SERIES OF DYES.
In this series a total number of 28 dye samples were prepared using 7 different pyrazolones.
These included1(4-sulfophenyl)-3-methyl-5-pyrazolone (SPMP), 1(4-sulfophenyl)-3-carboxy-5-
pyrazolone (SPCP), 1-Phenyl-3-methyl-5-pyrazolone (PMP), 1(4-tolyl)-3-methyl-5-pyrazolone
(PTMP), 1(2-chlorophenyl)-3-methyl-5-pyrazolone [2ClPMP], 1(3-chlorophenyl)-3-methyl-5-
pyrazolone [3-ClPMP] and 1(2,5-dichloro-4-sulfophenyl)-3-methyl-5-pyrazolone [2,5-
diClSPMP] were used as couplers. Four dye samples were prepared with each coupler. The first
being an un-metallized dye and the three were chromium, iron and copper complexes
respectively. Chromium complexes were 2:1 type. A synthetic scheme for coupling and
metallization is presented on page 111 (Scheme 4.3).
The synthesis of pyrazolone acid dyes 8a-g (229, 233, 237, 241, 245, 249, 253) involving 1-(p-
sulphophenyl)-3-methyl-5- pyrazolone as diazo component and their chromium (III), iron (II)
and copper (II) complexes (9a-g, 10a-g and 11a-g) was achieved by following a four step
procedure consisting of synthesis of 4-amino-1-(p-sulphophenyl)-3-methyl-5-pyrazolone,
diazotization, coupling with different pyrazolone couplers and their metal complex formation
(Scheme 4.3 and 4.4). The rational for selection of these dyes for synthesis, is to acquire various
scaffolds of this nature by metallization and to observe their shade and dyeing properties on
leather. Accordingly, 4-amino-1-(p-sulphophenyl)-3-methyl-5-pyrazolone was synthesized by
nitrosation of 1-(p-sulphophenyl)-3-methyl-5- pyrazolone (1) with NaNO2 and HCl at low
temperature 0-5oC. Nitroso derivative of 1-(p-sulphophenyl)-3-methyl-5- pyrazolone was
reduced with acetic acid and zinc dust at room temperature to 4-amino-1-(p-sulphophenyl)-3-
methyl-5-pyrazolone which was diazotized with NaNO2 and HCl, and coupled with couplers 2a-
g at low temperature to afford 8a-g (229, 233, 237, 241, 245, 249, 253). Synthesis of this diazo
intermediate has been confirmed from X-ray of its crystal. Coupling was made in alkaline
medium to do the reaction at C-four position of pyrazolone derivatives which is active methylene
position having acidic hydrogens sensitive to alkali and alkaline medium increases the
110
nucleophilicity of carbon which attacks on nitrogen of diazo component. Coupling was achieved
at room temperature with continuous stirring for 2.5h. Synthesized dyes 8a-g were precipitated
on completion of reaction by changing the pH of solution to acidic at 4.0 with HCl. Dyes were
dried and purified in ethanol. Metallization of above synthesized dyes was done by treating the
alkaline solution of dyes with Cr(OOCCH3)3, FeSO4.7H2O and, CuSO4.5H2O with continuous
stirring and heating the reaction mixture at 55-70oC for 4-5 h until the confirmation about
completion of reaction was observed by taking the TLC of reaction mixture in 9:1 chloroform
and methanol. Dyes were precipitated with addition of HCl, filtered and dried in oven at 70 oC.
Dyes were again recrystallized from ethanol, dried, weighed and determined the percentage
yield.
NN
CH3
OH
SO3H
NN
CH3
O
SO3H
N OH
NaNO2 + HCl
0 - 5 oC
NN
CH3
OH
SO3H
NH3 Cl
Zn + HCl
100 - 105 oC
+ -
NN
CH3
O-
SO3H
N+
N
NaNO2 + HCl
0 - 5 oC
NN
R1
OH
R3
R2
R4R5
NN
CH3
O-
SO3H
N+
N
+
NN
R1
OH
R3
R2
R4
NN
CH3
OH
SO3H
NN
R5
pH 8.0 - 8.5
15 - 25 oC8a-g
9,10 a-g
8a,R2,R4,R5=H,R1=CH3,R3=SO3H
8b,R2,R4,R5=H,R1=COOH,R3=SO3H
8c,R2, R3 ,R4,R5=H,R1=CH3
8d,R2,R4,R5=H,R1,R 3=CH3
8e,R2, R3 =H,R1=CH3,R4=SO3H,R5=H
8f,R2, R3 =H,R1=CH3,R4=Cl,R5=H
8g,R2,R5=Cl,R1=CH3,,R 3=SO3H,R4=H
9a-g dyes = 231,235,239,243,247,251,255
8a-g dyes = 229,233,237,241,245,249,253
OH2
OH2OH2
HO3S
N
N
CH3
O
NN
N
N
R1
O
R3
R2 R4
R5
M
10a-g dyes = 232,236,240,244,248,252,256
4a-b Metal Salts 55-70 oC
4a = FeSO4.7H2O
4b = CuSO4.5H2O
Scheme 4.3; Synthesis of acid dyes 8a-g, their Fe2+
(9a-g) and Cu2+
(10a-g) dyes (229-256).
111
NN
CH3
OH
SO3H
NN
CH3
O
SO3H
N OH
NaNO2 + HCl
0 - 5 oC
NN
CH3
OH
SO3H
NH3 Cl
Zn + HCl
100 - 105 oC
+ -
NN
CH3
O-
SO3H
N+
N
NaNO2 + HCl
0 - 5 oC
NN
R1
OH
R3
R2
R4R5
NN
CH3
O-
SO3H
N+
N
+
NN
R1
OH
R3
R2
R4
NN
CH3
OH
SO3H
NN
R5
pH 8.0 - 8.5
15 - 25 oC
HO3S
N
N
CH3
O
NN
N
N
R1
O
R3
R2 R4
SO3H
N
N
CH3
O
NN
N
N
R1
O
R3
R2R4
Cr-
R5
R5
Cr(CH3COO)3100 - 105 oC
8a-g
11a-g
8a,R2,R4,R5=H,R1=CH3,R3=SO3H
8b,R2,R4,R5=H,R1=COOH,R3=SO3H
8c,R2, R3 ,R4,R5=H,R1=CH3
8d,R2,R4,R5=H,R1,R 3=CH3
8e,R2, R3 =H,R1=CH3,R4=SO3H,R5=H
8f,R2, R3 =H,R1=CH3,R4=Cl,R5=H
8g,R2,R5=Cl,R1=CH3,,R 3=SO3H,R4=H
11a-g dyes = 230,234,238,242,246,250,254
8a-g dyes = 229,233,237,241,245,249,253
Scheme 4.4; Synthesis of pyrazolone dyes 8a-g and their Cr3+
(11a-g) complex dyes (229-254).
4.6.1 SPMP dyes.
Four dye samples were prepared with 1(4-sulfophenyl)-3-methyl-5-pyrazolone (SPMP). The first
being an un-metallized dye and the three were chromium, iron and copper complexes
respectively. Chromium complex was 2:1 type. The detailed properties of SPMP dyes are given
in table 4.11.
112
Table-4.11; Physical properties of dyes 229-232
UV-Visible data presented in Table-4.11 is supported by UV-Visible Spectra-8(Figure 4.15).
The un-metallized dye 229 (8a) was a yellow dye with λmax 430 nm and absorbance 2.1. Its
metallization with chromium had changed its color to olive brown and λmax to 480 nm with
absorbance 3.2 (dye 230), showing a bathochromic shift of 50 nm with a hyperchromic effect of
1.1.
On the other hand metallization of dye 229 (8a) with iron also produced an olive brown dye (dye
231) with λmax 440 nm and absorbance 2.8, showing a bathochromic shift of 10 nm with a
hyperchromic effect of 0.7.
While metallization of dye 229 (8a) with copper resulted in the formation of a yellow dye 232
(10a) with λmax 460 nm and absorbance 3.0, showing a bathochromic shift of 30 nm with a
hyperchromic effect of 0.9.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
229 N
N
CH3
OH
HO3SN N
N
N
CH3
OH
SO3H
C20H18N6
O8S2
Orange/
Yellow 430/2.1 Water
230
N
N
CH3
O
HO3SN N
N
N
CH3
O
SO3H
N
N
CH3
O
HO3SN N
N
N
CH3
O
SO3H
Cr-H
+
C40H32Cr
N12O16S4
Brown/
Olive
Brown
480/3.2 Water
231
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
O
SO3H
Fe
C20H22Fe
N6O11S2
Olive/
Olive
Brown
440/2.8 Water
232
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
O
SO3H
Cu-
C20H18Cu
N6O9S2
Olive /
Yellow 460/3.0 Water
113
Figure 4.15; UV-Visible Spectra-8 of dyes 229-232 (4848-umd = dye 229,
4848-Cr = dye 230, 4848-Fe = dye 231 and 4848- Cu = dye 232).
4.6.2 SPCP Dyes.
Four dye samples were prepared with 1(4-sulfophenyl)-3-carboxyl-5-pyrazolone (SPCP). The
first dye was an un-metallized one and the other three were chromium, iron and copper
complexes respectively. Chromium complex was 2:1 type. The detailed properties of SPCP dyes
are given in Table-4.12
114
Table-4.12; Physical properties of dyes 233-236
The UV-Visible data presented in Table-4.12 are supported by UV-Visible Spectra-9 (Figure
4.15). The un-metallized dye 233 (8b) was a yellow dye with λmax 500 nm and absorbance 3.0.It
had three absorptions owing to π → π* and n → n
*. Its metallization with chromium had changed
its color to Bordeaux, λmax to 490 nm and absorbance 2.7 (dye 234), showing a hypsochromic
shift of 10 nm with a hypochromic effect of 0.3.
On the other hand metallization of dye 233 with iron produced a yellowish brown dye (dye 235)
with λmax 450 nm and absorbance 3.7, showing a hypsochromic shift of 50 nm with a
hyperchromic effect of 0.7.While metallization of dye 233 with copper resulted in the formation
of a yellowish orange dye (dye 236) with λmax 460 nm and absorbance 3.1, showing a
hypsochromic shift of 40 nm with a hyperchromic effect of 0.1.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
233 N
N
CH3
OH
HO3SN N
N
N
HOOC
OH
SO3H
C20H16N6
O10S2
Orange/
Yellow
360/1.2,
460/3.2,
500/3.0
Water
234
N
N
CH3
O
HO3SN N
N
N
HOOC
O
SO3H
N
N
CH3
O
HO3SN N
N
N
HOOC
O
SO3H
Cr-H
+
C40H29Cr
N12O20S4
Reddish
Brown/
Bordeaux
370/1.7,
490/2.7 Water
235
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
HOOC
O
SO3H
Fe
C20H20Fe
N6O13S2
Black/
Yellowish
Brown
360/3.6,
450/3.7 Water
236
OH2
N
N
CH3
O
HO3SN N
N
N
HOOC
O
SO3H
Cu-
C20H16Cu
N6O11S2
Grey /
Yellowish
Orange
360/1.5,
460/3.1 Water
115
Figure 4.16; UV-Visible Spectra-9 of dyes 233-236 (4842-umd = dye 233,
4842-Cr = dye 234, 4842-Fe = dye 235 and 4842- Cu = dye 236)
4.6.3 PMP Dyes.
Four dye samples were prepared with 1-Phenyl-3-methyl-5-pyrazolone (PMP). The first dye
being an un-metallized one and the other three were chromium, iron and copper complexes
respectively. Chromium complex was 2:1 type. The detailed properties of PMP dyes are given in
table 4.13.
116
Table-4.13; Physical properties of dyes 237-240
The UV-Visible data presented in Table-4.13 are supported by UV-Visible Spectra-10 (Figure
4.17).The un-metallized dye 237 (8c) was an orange dye with λmax 440 nm and absorbance 1.6.Its
metallization with chromium had changed its color to yellow with λmax 450 nm and absorbance
1.3 (dye 238), showing a hyperchromic shift of 10 nm with a hypochromic effect of 0.3.
On the other hand metallization of dye 237 (8c) with iron produced a Yellowish Brown dye (dye
239) with λmax 410 nm and absorbance 0.9, showing a hypsochromic shift of 30 nm with a
hypsochromic effect of 0.5. While metallization of dye 237 (8c) with copper resulted in the
formation of a reddish violet dye (dye 240) with λmax 440 nm and absorbance 0.4 , showing no
change of λmax but a hypsochromic effect of 1.2.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
237 N
N
CH3
OH
HO3SN N
N
N
CH3
OH
C20H18N6
O5S
Reddish
Orange/
Reddish
Orange
440/1.6 Water
238
N
N
CH3
O
HO3SN N
N
N
CH3
O
N
N
CH3
O
HO3SN N
N
N
CH3
OCr
-H+
C40H33Cr
N12O10S2
Olive/
Yellow 450/1.3 Water
239
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OFe
C20H22Fe
N6O8S
Olive
Brown/
Yellowish
Brown
430/0.9 Water
240
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OCu-
C20H18Cu
N6O6S
Tan/
Reddish
Violet
440/0.4 Water
117
Figure 4.17; UV-Visible Spectra-10 of dyes 237-240 (4822-umd = dye 237,
4822-Cr = dye 238, 4822-Fe = dye 239 and 4822- Cu = dye 240)
4.6.4 PTMP dyes.
Four dye samples were prepared with 1(p-Tolyl)-3-methyl-5-pyrazolone (PTMP). The first dye
was an un-metallized one and the other three were chromium, iron and copper complexes
respectively. Chromium complex was 2:1 type. The detailed properties of PTMP dyes are given
in Table 4.14.
118
Table-4.14; Physical properties of dyes 241-244
The UV-Visible data presented in Table-4.14 is supported by UV-Visible Spectra-11 (Figure
4.17). The un-metallized dye 241 (8d) was an orange dye with λmax 440 nm and absorbance 1.7.
Its metallization with chromium had changed its color to greenish yellow with λmax 460 nm and
absorbance 1.6 (dye 242), with a bathochromic shift of 10nm and a hypochromic effect of 0.1.
On the other hand metallization of dye 241 with iron produced a reddish yellow dye (dye 243)
with λmax 430 nm and absorbance 1.6, showing a hypsochromic shift of 10 nm. While
metallization of dye 241 (8d) with copper resulted in the formation of a greenish yellow dye (dye
244) with λmax 440 nm and absorbance 2.3 , showing a hyperchromic effect of 0.6.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
241 N
N
CH3
OH
HO3SN N
N
N
CH3
OH
CH3
C21H20N6
O5S
Orange/
Reddish
Orange
440/1.7 Water
242
N
N
CH3
O
HO3SN N
N
N
CH3
O
N
N
CH3
O
HO3SN N
N
N
CH3
OCr
-
CH3
CH3
H+
C42H37Cr
N12O10S2
Olive/
Greenish
Yellow
460/1.6 Water
243
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OFe
CH3
C21H24Fe
N6O8S
Olive/
Reddish
Yellow
430/1.6 Water
244
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OCu-
CH3
C21H20Cu
N6O6S
Olive/
Greenish
Yellow
440/2.3 Water
119
Figure 4.18; UV-Visible Spectra-11 of dyes 241-244 (4811-umd = dye 241,
4811-Cr = dye 242, 4811-Fe = dye 243 and 4811- Cu = dye 244).
4.6.5 3-SPMP dyes.
Four dye samples were prepared with 1(3-sulphophenyl)-3-methyl-5-pyrazolone (3-SPMP). The
first dye being an un-metallized one and the other three were chromium, iron and copper
complexes respectively. Chromium complex was 2:1 type. The detailed properties of 3-SPMP
dyes are given in Table-4.15.
120
Table-4.15; Physical properties of dyes 245-248
The UV-Visible data presented in Table-4.15 are supported by UV-Visible Spectra-12 (Figure
4.18).The un-metallized dye 245 (8e) was an orange dye with λmax 430 nm and absorbance 1.3.Its
metallization with chromium had changed its color to yellow with λmax 460 nm and absorbance
1.1 (dye 246), showing a bathochromic shift of 30 nm with a hypochromic effect of 0.2.
On the other hand metallization of dye 245 (8e) with iron also produced a yellowish dye (dye
247) with λmax 410 nm and absorbance 1.85, showing a hypsochromic shift of 20 nm with a
hyperchromic effect of 0.55. While metallization of dye 245 (8e) with copper resulted in the
formation of a greenish yellow dye(dye 246) with λmax 430 nm and absorbance 1.85, that showed
a hyperchromic effect of 0.55.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
245 N
N
CH3
OH
HO3SN N
N
N
CH3
OH SO3H
C20H18N6
O8S2
Tan/
Reddish
Orange
430/1.3 Water
246
N
N
CH3
O
HO3SN N
N
N
CH3
O
N
N
CH3
O
HO3SN N
N
N
CH3
OCr
-
SO3H
SO3HH
+
C40H33Cr
N12O16S4
Dark
Brown/
Yellow
360/0.8,
460/1.1 Water
247
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OFe SO3H
C20H22Fe
N6O11S2
Gray/
Yellow 410/1.85 Water
248
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OCu-
SO3H
C20H18Cu
N6O9S2
Yellowish
Brown/
Greenish
Yellow
430/1.85 Water
121
Figure 4.19; UV-Visible Spectra-12 of dyes 245-248 (8-3SPMP-umd = dye 245,
48-3SPMP-Cr = dye 246, 48-3SPMP-Fe = dye 247 and 48-3SPMP- Cu = dye 248).
4.6.6 3-ClPMP Dyes.
Four dye samples were prepared with 1(3-chlorophenyl)-3-methyl-5-pyrazolone (3-ClPMP). The
first dye being an un-metallized one and the other three were chromium, iron and copper
complexes respectively. Chromium complex was 2:1 type. The detailed properties of 3-ClPMP
dyes are given in Table-4.16.
122
Table-4.16; Physical properties of dyes 249-252
The UV-Visible data presented in Table-4.16 are supported by UV-Visible Spectra-13 (Figure
4.19). The un-metallized dye 249 (8f) was an orange dye with λmax 440 nm and absorbance
2.7.Its metallization with chromium had changed its color to yellowish brown with λmax 450 nm
and absorbance 1.9 (dye 250), showing a bathochromic shift of 10 nm with a hypochromic effect
of 0.6.
On the other hand metallization of dye 249 (8f) with iron produced a yellowish brown dye (dye
251) with λmax 420 nm and absorbance 3.0, showing a hypsochromic shift of 20 nm with a
hyperchromic effect of 0.3.While metallization of dye 249 (8f) with copper resulted in the
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λ
max(nm)/
Absorba-
nce
Solublity
249 N
N
CH3
OH
HO3SN N
N
N
CH3
OH Cl
C20H17Cl
N6O5S
Reddish
Orange/
Reddish
Orange
440/2.7 Water
250
N
N
CH3
O
HO3SN N
N
N
CH3
O
N
N
CH3
O
HO3SN N
N
N
CH3
OCr
-
Cl
ClH
+
C40H31Cl2
CrN12O10S2
Yellowish
Brown/
Yellowish
Brown
450/1.9 Water
251
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OFe Cl
C20H21Cl
FeN6O8S
Dark
Brown/
Yellowish
Brown
420/3.0 Water
252
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OCu-
Cl
C20H17Cl
CuN6O6S
Pale/
Greenish
Yellow
440/2.5 Water
123
formation of a greenish yellow dye(dye 252) with same λmax 440 nm and absorbance 2.5, that
showed a hypochromic effect of 0.2.
Figure 4.20; UV-Visible Spectra-13 of dyes 249-252 (48-3ClPMP -umd = dye 249,
48-3ClPMP -Cr = dye 250, 48-3ClPMP -Fe = dye 251 and
48-3ClPMP - Cu = dye 252).
4.6.7 2,5-diClSPMP Dyes
Four dye samples were prepared with 1-(2,5-dichloro-4-sulphophenyl)-3-methyl-5-pyrazolone
(2,5-diClSPMP). The first dye being an un-metallized one and the other three were chromium,
iron and copper complexes respectively. Chromium complexes were of 2:1 type. The detailed
properties of 2,5-diClSPMP dyes are given in Table-4.17.
124
Table-4.17; Physical properties of dyes 253-256
The UV-Visible data presented in Table-4.17 is supported by UV-Visible Spectra-14 (Figure
4.20).The un-metallized dye 253 (8g) was an orange dye with λmax 440 nm and absorbance 2.65.
Its metallization with chromium had changed its color to reddish yellow with λmax 460 nm and
absorbance 2.3 (dye 254), showing a bathochromic shift of 20 nm with a hypochromic effect of
0.35.
On the other hand metallization of dye 253 (8g) with iron produced a reddish yellowish dye (dye
255) with λmax 420 nm and absorbance 1.8, it showed a hypsochromic shift of 20 nm with a
hypochromic effect of 0.85. While metallization of dye 253 with copper resulted in the formation
of a greenish yellow dye (dye 256) with λmax 450 nm and absorbance 2.6, showing a
bathochromic shift of 10 nm.
Dye
# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
253 N
N
CH3
OH
HO3SN N
N
N
CH3
OH Cl
Cl
SO3H
C20H16Cl2
O8S2
Orange/
Reddish
Orange
440/2.65 Water
254
N
N
CH3
O
HO3SN N
N
N
CH3
O
N
N
CH3
O
HO3SN N
N
N
CH3
OCr
-
Cl
Cl
Cl
SO3H
SO3H
Cl
H+
C40H29Cl4
CrN12O16S4
Olive /
Reddish
Yellow
460/2.3 Water
255
OH2OH2OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OFe Cl
Cl
SO3H
C20H20Cl2
FeN6O11S2
Olive /
Reddish
Yellow
420/1.8 Water
256
OH2
N
N
CH3
O
HO3SN N
N
N
CH3
OCu-
Cl
Cl
SO3H
C20H16Cl2
CuN6O9S2
Olive /
Greenish
Yellow
450/2.6 Water
125
Figure 4.21; UV-Visible Spectra-14 of dyes 253-256 (4849 -umd = dye 253,
4849-Cr = dye 254, 4849 -Fe = dye 255 and 4849 - Cu = dye 256)
4.7 Spectral Properties of Pyrazolone Dyes
The infrared spectra of the synthesized acid dyes and their metal complexes exhibited absorption
peaks due to COOH, O-H, Ar-H, C-H, C=O, C=C, N=N, SO3H, C-O, C-Cl and O-M stretching
and bending vibrations at 3565, 3460-3485, 3050-3062, 2920-2932, 1720, 1619-1665, 1531-
1591, 1441-1469, 1209-1272, 1040-1085, 853-885 770-772 and 520-560 cm-1
as depicted from
their FTIR spectra in Figure 4.22 and 4.23.
Specifically speaking, using FTIR spectrum of dyes 8g, a broad band is observed in the range
3200-3550 cm-1
which was due to H-bonding of COOH and O-H groups in close proximity to
each other in dyes. Aromatic (benzene) rings are evidenced by presence of peaks in the range
3460-3485 cm-1
due to C-H stretching of unsaturated carbon atoms which are further confirmed
by their peaks at 1619-1665 and 1531-1591 cm-1
.
A peak is observed in the range 1720cm-1
which is due to carbonyl functionality of dye 8g. The
absorption bands at 1428-1455 cm-1
depicted the presence of N=N stretching vibrations of dyes
and this peak is common in all dyes. Synthesis of dyes 8a-g has been confirmed by their FTIR
spectra. The metal complexes of dyes 8a-f have been inveterated by the presence of peaks at low
126
frequency region at 520-565cm-1
because of large masses of metal atoms and these peaks are
absent in their respective FTIR spectra.
Figure 4.22; FTIR Spectrum of Pyrazolone Acid Dye 253 (8g)
Figure 4.23; FTIR Spectrum Cu (II) complex 256 (10g) of pyrazolone acid dye 253 (8g)
The 1H-NMR spectrum of all dyes 8a-g (229, 233, 237, 241, 245, 249, 253) showed signals
down field at 9.19-10.00 ppm due to OH groups present in the coupling and diazo components of
dyes, and are highly deshielded due to H-bonding.
127
Similarly symmetrical doublet peaks at 7.71-7.92 and 8.03 -8.15 with same coupling constant
are observed in all dyes having benzene ring containing SO3H group and SO3H is evidenced
from its peak at range 6.65-7.70 ppm. Methyl group singlet peak is also common in all dyes and
is present in the range 2.61-2.68 ppm, which is further evidenced from their 13
C-NMR spectra
and is present at range 13.25-15.33 ppm. All these dyes 8a-g (229, 233, 237, 241, 245, 249, 253)
are compounds of a series where difference arises in case coupling component containing
different substituents. Benzene ring proton peaks are present at positions 7.59-7.93 and 7.38-7.45
ppm are common in all dyes. Multiplicity of these peaks is different in different dyes. Methyl
group in spectrum of dye 8g (253) has exhibited peak at 2.29 ppm while methine hydrogen is at
5.95 ppm and this highly deshielded. Mutually coupled hydrogens in the diazo component
showed doublet peaks at 7.68 and 7.89 ppm having coupling constant J = 8.7Hz which
confirmed their o-position, while hydroxyl and carboxyl group peaks are at 10.30 and 12.18 ppm
respectively (Figure 4.24).
The coupling component of dye showed multiplet peak at 7.71-7.76 ppm was due to aromatic
protons. 13
C-NMR of all dyes showed aromatic peaks in range 117-154 ppm. Peak at 163.73 ppm
in 13
C-NMR spectrum of dye 8g (253) was due to COOH group and CH3 group peak was at 12
ppm. Methine carbon was found at 89 ppm, as this hydrogen was involved in keto enol
tautomerism (Figure 4.25). The presence of peaks for respective carbons in spectrum is in favour
of synthesized dye 8g (253). Similarly other dyes have been confirmed from 1H and
13C-NMR
spectra.
128
Figure 4.24; 1H-NMR Spectrum of Pyrazolone Acid Dye 8g (253)
129
Figure 4.25; 13
C-NMR Spectrum of Pyrazolone Acid Dye 8g (253)
4.8 The Dyeing Properties of Pyrazolone Dyes.
The dyeing properties of pyrazolone dyes have been found to be very good. Almost all properties
have been found to be of very high value (4-5).However, chromium complexes were the best
ones. The un-metalized dye-ligands had low values as per expectation due to the presence of free
hydroxyl groups. The detail of dyeing properties of pyrazolone dyes is given in Table-4.18
130
Table -4.18 Dyeing properties of pyrazolone dyes (229-256)
The data presented in Table-4.18 are supported by Shade Card-2 (part-a and part-b).
Dye
#
2%Shade on
Leather
5%hade on
Leather
Penetr-
ation
Washing
Fastness
Light
Fastness
Perspiration
Fastness
229 Beige Yellowish
Orange 3 3-4 2-3 3-4
230 Dark Yellowish
Beige
Yellowish
Orange 4 3-4 4-5 4-5
231 Yellowish Beige Dark Beige 5 4-5 5 5
232 Greenish Yellow Greenish Yellow 4 3-4 3-4 4-5
233 Pink Reddish Orange 3 3-4 3-4 3-4
234 Reddish Beige Reddish Orange 4 3-4 4-5 4-5
235 Reddish Beige Olive 5 4-5 5 5
236 Yellowish Beige Dark Yellowish
Beige 3 3-4 3-4 4-5
237 Yellowish Orange Dark Yellowish
Orange 2 2-3 2-3 3-4
238 Yellowish Orange Dark Yellowish
Orange 4 3-4 4-5 4-5
239 Beige Yellowish Brown 5 4-5 5 5
240 Light greenish
Yellow Yellowish Beige 3 3-4 3-4 4-5
241 Yellowish Orange Reddish Orange 2 2-3 2-3 3-4
242 Yellowish Orange Dark Yellowish
Orange 4 3-4 4-5 4-5
243 Greenish Olive Yellowish Brown 5 4-5 5 5
244 Yellow Greenish Yellow 3 3-4 3-4 4-5
245 Dark Yellowish
Beige
Yellowish
Orange 2 2-3 2-3 3-4
246 Yellowish Beige Yellowish
Orange 4 3-4 4-5 4-5
247 Olive Reddish Beige 5 4-5 5 5
248 Greenish Yellow Dark Greenish
Yellow 3 3-4 3-4 4-5
249 Orange Reddish Orange 2 2-3 2-3 3-4
250 Yellowish Orange Reddish Brown 4 3-4 4-5 4-5
251 Olive Brown 5 4-5 5 5
252 Yellow Dark Yellow 3 3-4 3-4 4-5
253 Yellowish Beige Yellowish Olive 2 2-3 2-3 3-4
254 Beige Dark Beige 4 3-4 4-5 4-5
255 Light Beige Dark Beige 5 4-5 5 5
256 Greenish Yellow Deep Yellow 3 3-4 3-4 4-5
131
132
A mutual comparison of shades of all pyrazolone dyes is presented in shade comparison 5-8 for
un-metallized, chromium, iron and copper complexes respectively.
133
Shade comparison -5
COMPARISON OF UN-METALIZED DYES OF PYRAZOLONE SERIES
Dye # Pyrazolone 2% Shade 5% Shade
229 SPMP
233 SPCP
237 PMP
241 PTMP
245 3SPMP
249 3Cl PMP
253 2,5-DiClSPMP
As it is clear from Shade comparison-5 (un-metallized pyrazolone dyes) almost all of the dyes
had similar shades in 5%dyed leathers, with a variation of only depth of shades. This can be
attributed to the fact that again the main chromophoric system remained the same in all dyes.
The variation of the depth can be attributed to the participation of peripheral group’s variation of
difference of pyrazole moieties.The dye of SPCP (1-sulphophenyl-3-carboxypyrazol-5-one)has
been found to be much redder; this can be due to the presence of 3-carboxy group.Similarly the
dye with 1-(2,5-dichloro-4-sulphophenyl)-3-methyl pyrazol-5-one have been found to be much
greener in tone this can be attributed to the presence of two chlorine atoms on the benzene ring.
134
Shade comparison -6
COMPARISON OF CHROMIUM METALLIZED DYES OF PYRAZOLONE SERIES
Dye # Pyrazolone 2% Shade 5% Shade
230 SPMP
234 SPCP
238 PMP
242 PTMP
246 3-SPMP
250 3-Cl PMP
254 2,5-diClSPMP
As it is clear from Shade comparison-6 (chromium-metallized dyes), almost all of the dyes had
same shades like their parent dyes but with a much yellower tone. These were olive to reddish
brown in color with a variation of depth of shades. This can be attributed to the fact that the main
chromophoric system remained the same in all chromium-metallized dyes. However the
chromium complexes of SPCP, PMP and 3ClPMP were much darker in shades as compared to
3SPMP,4SPMP and 2,5-diClSPMP. This variation of the depth can be attributed to the
participation of peripheral group’s variation of different pyrazolones.
135
Shade comparison -7
COMPARISON OF IRON METALIZED DYES OF PYRAZOLONE SERIES
Dye
# Pyrazolone 2% Shade 5% Shade
231 SPMP
235 SPCP
239 PMP
243 PTMP
247 3SPMP
251 3Cl PMP
255 2,5-diClSPMP
As it is clear from Shade comparison-7 (iron-metallized pyrazolone dyes), almost all of the
dyes had different shades as compared to their un-metallized parent dyes. Most of the shades are
much greener in tone. These were olive to reddish brown in color with a variation of depth of
shades. This can be attributed to the fact that, as with the other dyes in the series, the main
chromophoric system remained the same in all iron-metalized dyes. However the iron complexes
of PMP and 3ClPMP were much darker in shades as compared to 3SPMP, 4SPMP and
2, 5-diClSPMP.
136
Shade comparison -8
COMPARISON OF COPPER METALLIZED DYES OF PYRAZOLONE SERIES
As it is clear from Shade comparison-8 (copper-metallized pyrazolone dyes), almost all of the
dyes had different shades as compared with their parent dye ligands. Copper complexes were
very greenish yellow as per our expectation. These were olive to greenish yellow except for
SPCP with reddish brown in color. This can be attributed to the fact that the main chromophoric
system remained the same in all copper-metalized dyes. However chromium complex of 2,5-
diClSPMP was the most greenish due to the presence of two chlorine atoms in the coupler.
Dye # Pyrazolone 2% Shade 5% Shade
232 4SPMP
236 SPCP
240 PMP
244 PTMP
248 3-SPMP
252 3-Cl PMP
256 2,5-diClSPMP
137
4.9 Synthesis of Naphthol Series of Dyes
In this series a total number of 20 dye samples were prepared. A total number of 5 different
naphthols namely β-naphthol, Schaeffer’s Acid, R-Acid, H-Acid and N-phenyl J-Acid were used
as couplers. Four dye samples were prepared with each coupler. The first being un-metallized
dye and the three were chromium, iron and copper complexes respectively. Chromium
complexes were of 2:1 type. A scheme of coupling and metallization for the synthesis of β-
naphthol type dyes is given in scheme 4.5.
The synthesis of pyrazolone naphthol acid dyes 13a-e (257, 261, 265, 269, 273) involving 4-
amino-1(p-sulphophenyl)-3-methyl-5-pyrazolone as diazo component and their chromium (III),
iron (II) and copper (II) complexes was achieved by following a five step procedure. It consisted
of nitrosation of SPMP, reduction to 4-amino-1-(p-sulphophenyl)-3-methyl-5-pyrazolone,
diazotization, coupling with different naphthol derivatives and their metal complex formation.
The objective for selection of these dyes for synthesis was to acquire various scaffolds of this
nature by metallization and to observe their shade and dyeing properties on leather.
Accordingly, 4-amino-1-(p-sulphophenyl)-3-methyl-5-pyrazolone was synthesized by nitrosation
of 1-(p-sulphophenyl)-3-methyl-5-pyrazolone (144) with NaNO2 and HCl at low temperature 0-
5°C. The nitroso derivative of 1-(p-sulphophenyl)-3-methyl-5- pyrazolone was reduced with zinc
and HCl at high temperature(100-105°C) to give 4-amino-1-(p-sulphophenyl)-3-methyl-5-
pyrazolone hydrochloride. It was diazotized with NaNO2 and HCl, and coupled with napthol
derivatives at 15-25°C. The Synthesis of diazo intermediate has been confirmed from X-ray of
its crystal. Dyes were purified in ethanol. Metallization of above synthesized dyes was done by
treating the alkaline solution of dye with Cr(CH3COO-)3, FeSO4.7H2O and CuSO4.5H2O with
continuous stirring and heating of the reaction mixture at 100-105°C for chromium and 55-70°C
for iron and copper.It took 4-5h to complete of metallization, as was observed by checking the
TLC of reaction mixture in 9:1 chloroform and methanol. Dyes were precipitated at low pH and
temperature by the addition of HCl and salt, filtered and dried in an oven at 70°C. Dyes were
again purified from ethanol, dried, weighed and the percentage yield was determined. The yields
ranged from 83-96%.
138
N
NCH3
N+
O-
Na+ -O3S
N
R1
R2R3
OH
Couplers (12a-e)Diazo of SPMP
15 - 25 oC Na2CO3/NaOH
+
N
N
CH3
N
OH
HO3S
N
R1
R2
R3OH
OH2OH2 OH2
N
N
CH3
N
O
HO3S
N
R1
R3OM
R2
FeSO4/CuSO4
65 - 70 oCCr(CH3COO-)3
100 - 105 oC
Dyes(13a-e)
Dyes(14a-e)
M = Fe2+
/Cu 2+
Dyes 15,16a-e
Dyes(14a-e) Cr3+
Dyes= Dyes 258,262,266,270,274
Dyes(13a-e) = Dyes 257,261,265,269,273
Dyes(15a-e) Fe 2+
Dyes= Dyes 259,263,267,271,275
Dyes(16a-e) Cu 2+
Dyes= Dyes 260,264,268,272,276
N
N
CH3
NO
HO3S
N
R1
R3O
R2
N
N
CH3
NO
SO3H
N
R1
R3 OCr
-
R2
Where ; R1=H, R2=R3 = H/SO3H
Scheme-4.5; Synthesis of Naphthol dyes 13a-e and their Fe (15a-e), Cu (16a-e) complexes (dyes
257-276)
4.9.1 β-Naphthol dyes.
Four dye samples were prepared with β-naphthol. The first dye being an un-metallized one and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was of 2:1type. The detailed properties of β-naphthol dyes are given in Table-4.19.
139
Table-4.19; Physical properties of dyes 257-260
The UV-Visible data presented in Table-4.19 are supported by UV-Visible Spectra-15 (Figure
4.26). The un-metallized dye 257 was a yellowish orange dye with λmax 490 nm and absorbance
2.2.Its metallization with chromium had changed its color to pink with λmax 520 nm and
absorbance 1.35 (dye 258), showed a bathochromic shift of 30 nm with a hypochromic effect of
0.85. On the other hand metallization of dye 257 with iron produced an olive brown dye (dye
259) with λmax 360 nm and absorbance 0.8, showing a hypsochromic shift of 130 nm with a
hypochromic effect of 1.4.
While metallization of dye 257 with copper resulted in the formation of a reddish brown dye(dye
260) with λmax 470 nm and absorbance 0.85 , showing a hypsochromic shift of 20 nm with a
hypochromic effect of 1.35.
Dye# Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λ max (nm)/
Absorba-
nce
Solubility
257 N
N
CH3
OH
HO3SN N
OH
C20H16N4
O5S
Orange/
Yellowish
Orange
360/0.9 ,
490/2.2 Water
258
N
N
CH3
O
HO3SN N
O
N
N
CH3
O
HO3SN N
OCr
-H
+
C40H29Cr
N8O10S2
Dark
Brown/
Pink
360/0.9 ,
520/1.35 Water
259
OH2OH2 OH2
N
N
CH3
O
HO3SN N
OFe
C20H20Fe
N4O8S
Dark
Brown/
Olive
Brown
360/0.8 Water
260
OH2
N
N
CH3
O
HO3SN N
OCu-
C20H16Cu
N4O6S
Dark
Brown/
Reddish
Brown
360/1.85 ,
470/0.85 Water
140
Figure 4.26; UV-Visible Spectra-15 of dyes 257-260 (4840-umd = dye 257,
4840-Cr = dye 258, 4840 -Fe = dye 259 and 4840 - Cu = dye 260)
4.9.2 Schaeffer’s acid Dyes.
Four dye samples were prepared with Schaeffer’s Acid (2-naphthol-6-sulphonic acid). The first
dye being an un-metallized one and the other three were chromium, iron and copper complexes
respectively. Chromium complex was of 2:1 type. The detailed properties of Schaeffer’s Acid
dyes are given in Table-4.20.
141
Table-4.20; Physical properties of dyes 261-264
The UV-Visible data presented in Table-4.20 are supported by UV-Visible Spectra-16 (Figure
4.27).The un-metallized dye 261 was a yellowish orange dye with λmax 480 nm and absorbance
1.05.Its metallization with chromium changed its color to pink with λmax 510 nm and absorbance
1.09 (dye 262), showing a bathochromic shift of 30 nm with a hyperchromic effect of 0.04.
On the other hand metallization of dye 261 (13b) with iron produced a beige dye (dye 263) with
λmax 450 nm and absorbance 1.59, showing a bathochromic shift of 30 nm with a hyperchromic
effect of 0.54.While metallization of dye 261 (13b) with copper resulted in the formation of a
reddish orange dye (dye 264) with λmax 470 nm and absorbance 1.5, showing a hypsochromic
shift of 10 nm with a hyperchromic effect of 0.45.
Dye# Dye Structure
Molecular
Formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorb-
ance
Solubiity
261 N
N
CH3
OH
HO3SN N
OH
SO3H
C20H16N4
O8S2
Tan/
Yellowish
Orange
360/0.55,
480/1.1 Water
262
N
N
CH3
O
HO3SN N
O
N
N
CH3
O
HO3SN N
OCr
-
SO3H
SO3H
H+
C40H29Cr
N8O16S4 Tan/Pink
360/1.05,
510/1.09 Water
263
OH2OH2 OH2
N
N
CH3
O
HO3SN N
OFe
SO3H
C20H20Fe
N4O11S2
Olive
Brown/
Beige
360/1.7,
450/1.59 Water
264
OH2
N
N
CH3
O
HO3SN N
OCu-
SO3H
C20H16Cu
N4O9S2
Tan/
Reddish
Orange
360/0.55,
470/1.5 Water
142
Figure 4.27; UV-Visible Spectra-16 of dyes 261-264 (4864 -umd = dye 261,
4864-Cr = dye 262, 4864 -Fe = dye 263 and 4864 - Cu = dye 264)
4.9.3 R-Acid dyes.
Four dye samples were prepared with R-Acid (2-naphthol-3,6-disulphonic acid). The 1st
dye
being un-metallized one and the other three were chromium, iron and copper complexes
respectively. Chromium complex was of 2:1 type. The detailed properties of R-Acid dyes are
given in Table-4.21.
143
Table-4.21; Physical properties of dyes 265-268
The UV-Visible data presented in Table-4.21.is supported by UV-Visible Spectra-17 (Figure
4.28).The un-metallized dye 265 (13c) was a reddish orange dye with λmax 470 nm and
absorbance 2.3. Its metallization with chromium changed its color to pink with λmax 540 nm and
absorbance 0.5 (dye 262), showing a bathochromic shift of 70 nm with a hypochromic effect of
1.8.On the other hand metallization of dye 265 (13c) with iron produced an olive brown dye (dye
267) with λmax 460 nm and absorbance 0.82, showing a hypsochromic shift of 10 nm with a
hypochromic effect of 1.48.
While metallization of dye 265 (13c) with copper resulted in the formation of a yellowish orange
dye (dye 268) with λmax 490 nm and absorbance 0.75, showed a bathochromic shift of 20 nm
with a hypochromic effect of 1.55.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
265 N
N
CH3
OH
HO3SN N
OH
SO3H
SO3H
C20H16N4
O11S3
Dark
Brown/
Reddish
Orange
360/1.1 ,
470/2.3 Water
266
N
N
CH3
O
HO3SN N
O
N
N
CH3
O
HO3SN N
OCr
-
SO3H
SO3H
SO3H
SO3H
H+
C40H29Cr
N8O22S6
Dark Tan/
Pink
360/0.55,
540/0.5 Water
267
OH2OH2 OH2
N
N
CH3
O
HO3SN N
OFe
SO3H
SO3H
C20H20Fe
N4O14S3
Dark
Brown/
Olive
Brown
360/0.7,
460/0.82 Water
268
OH2
N
N
CH3
O
HO3SN N
OCu-
SO3H
SO3H
C20H16Cu
N4O12S3
Yellowish
brown/
Yellowish
Orange
360/0.82,
490/0.75 Water
144
Figure 4.28; UV-Visible Spectra-17 of dyes 265-268 (48RA-umd = dye 265,
48RA-Cr = dye 266, 48RA -Fe = dye 267 and 48RA - Cu = dye 268).
4.9.4 H-Acid Dyes.
Four dye samples were prepared with H-Acid (1-amino-8-naphthol-3,6-disulphonic acid) in
basic coupling. The 1st
dye was un-metallized one and the other three were chromium, iron and
copper complexes respectively. Chromium complex was 2:1 type. The detailed properties of H-
Acid dyes are given in Table-4.22.
145
Table-4.22; Physical properties of dyes 269-272
The UV-Visible data presented in Table-4.22 are supported by UV-Visible Spectra-18 (Figure
4.29). The un-metallized dye 269 (13d) was an orange dye with λmax 520 nm and absorbance 0.7.
Its metallization with chromium changed its color to Violet with λmax 560 nm and absorbance 0.8
(dye 270), showing a bathochromic shift of 40 nm with a hyperchromic effect of 0.1.
On the other hand metallization of dye 269 (13d) with iron produced a yellowish brown dye (dye
271) with λmax 500 nm and absorbance 0.6, showing a hypsochromic shift of 20 nm with a
hyperchromic effect of 0.1. While metallization of dye 269 (13d) with copper resulted in the
formation of a reddish violet dye (dye 272) with λmax 440 nm and absorbance 1.1, showing a
hypsochromic shift of 80 nm with a hyperchromic effect of 0.4.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
269 N
N
CH3
OH
HO3SN N
SO3HHO3S
NH2OH
C20H17N5
O11S3
Brown/
Reddish
Orange
360/0.7,
520/0.7 Water
270
N
N
CH3
O
HO3SN N
SO3HHO3S
NH2O
N
N
CH3
O
HO3SN N
SO3HHO3S
NH2OCr
-H
+
C40H31Cr
N10O22S6
Violet/
Violet
360/1.5,
560/0.8 Water
271
OH2OH2OH2
N
N
CH3
O
HO3SN N
SO3HHO3S
NH2OFe
C20H21Fe
N5O14S3
Brown/
Yellowish
Brown
360/1.6,
500/0.6 Water
272
OH2
N
N
CH3
O
HO3SN N
SO3HHO3S
NH2OCu-
C20H17Cu
N5O12S3
Tan/
Reddish
Violet
360/1.5,
440/1.1 Water
146
Figure 4.29; UV-Visible Spectra-18 of dyes 269-272 (4824-umd = dye 269,
4824-Cr = dye 270, 4824 -Fe = dye 271 and 4824 - Cu = dye 272).
4.9.5 N-Phenyl J. Acid dyes.
Four dye samples were prepared with N-phenyl-J-Acid (6-anilino-1-naphthol-3-sulphonic acid).
The first dye was un-metallized one and the other three were chromium, iron and copper
complexes respectively. Chromium complex was 2:1 type. The detailed properties of NPJ-Acid
dyes are given in Table-4.23.
147
Table-4.23; Physical properties of dyes 273-276
Dye # Dye Structure Molecular
Formula(Calc.)
Powder/
Solution
Color
λmax(nm)
Absorba-
nce
Solubility
273 N
N
CH3
OH
HO3SN N
NHHO3S
OH
C26H21N5
O8S2
Orange/
Reddish
Orange
360/0.9,
480/1.2 water
274
N
N
CH3
O
HO3SN N
NHHO3S
O
N
N
CH3
O
HO3SN N
NHHO3S
OCr
-H+
C52H39Cr
N10O16S4
Violet/
Violet
360/0.7,
530/0.5 water
275
OH2OH2
OH2
N
N
CH3
O
HO3SN N
NHHO3S
OFe
C26H25Fe
N5O11S2
Black/
Reddish
brown
360/1.8,
490/1.3 water
276
OH2
N
N
CH3
O
HO3SN N
NHHO3S
OCu-
C26H21Cu
N5O9S2
Black/
Violet
Brown
360/1.1,
500/0.7 water
The UV-Visible data presented in Table-4.23 are supported by UV-Visible Spectra-19 (Figure
4.30).The un-metallized dye 273 (13d) was a reddish orange dye with λmax 480 nm and
absorbance 1.2. Its metallization with chromium changed its color to violet with λmax 530 nm and
absorbance 0.5 (dye 274), showing a bathochromic shift of 50 nm with a hypochromic effect of
0.7. On the other hand metallization of dye 273 with iron produced a reddish brown dye (dye
275) with λmax 490 nm and absorbance 1.3, showed a bathochromic shift of 10 nm with a
hyperchromic effect of 0.1.While metallization of dye 273 with copper resulted in the formation
of a violet brown dye (dye 276) with λmax 500 nm and absorbance 0.7, showing a bathochromic
shift of 20 nm with a hypochromic effect of 0.5.
148
Figure 4.30; UV-Visible Spectra-19 of dyes 273-276 (48108 -umd = dye 273,
48108-Cr = dye 274, 48108 -Fe = dye 275 and 48108 - Cu = dye 276).
4.10 The Dyeing Properties of Naphthol Dyes
The naphthol dyes were found to have very good dyeing properties. Almost all properties have
been found to be of very high value (4-5).However, chromium complexes have been found to be
the best ones. The un-metallized dye-ligands with low values were as per expectation due to the
presence of free hydroxyl groups. The dyeing properties of naphthol dyes are given in
149
Table-4.24
Table 4.24 Dyeing properties of Naphthol Series of Dyes.
The data presented in Table-4.31 are supported by Shade Card-3 part-a and part-b.
Dye
#
2%Shade on
Leather
5%Shade on
Leather Penetration
Washing
Fastness
Light
Fastness
Perspiration
Fastness
257 Orange Reddish Orange 3 3-4 2-3 3-4
258 Violet Bordeaux 4 3-4 4-5 4-5
259 Olive Brown Reddish Brown 5 4-5 5 5
260 Light Orange Reddish Orange 4 3-4 3-4 4-5
261 Light Orange Dark Yellowish
Orange 3 3-4 3-4 3-4
262 Light Pink Dark Pink 4 3-4 4-5 4-5
263 Olive Dark Olive 5 4-5 5 5
264 Yellowish
Orange Reddish Orange 3 3-4 3-4 4-5
265 Light Pink Reddish Orange 2 2-3 2-3 3-4
266 Pink Dark Pink 4 3-4 4-5 4-5
267 Olive Dark Olive 5 4-5 5 5
268 Reddish Beige Reddish Orange 3 3-4 3-4 4-5
269 Tan Dark Brown 2 2-3 2-3 3-4
270 Violet Brown Dark Violet
Brown 4 3-4 4-5 4-5
271 Brown Dark Brown 5 4-5 5 5
272 Olive Dark Olive 3 3-4 3-4 4-5
273 Tan Maroon 2 2-3 2-3 3-4
274 Light Violet Dark Violet 4 3-4 4-5 4-5
275 Brown Dark Brown 5 4-5 5 5
276 Light Brown Dark Brown 3 3-4 3-4 4-5
150
151
A mutual comparison of shades of naphthol dyes is presented in Shade Comparisons 9-12, for
un-metallized, chromium, iron and copper complexes respectively.
152
Shade comparison-9
COMPARISON OF UN-METALLIZED DYES OF NAPHTHOL SERIES
Dye # Naphthol 2% Shade 5% Shade
257 β- Naphthol
261 Schaeffer’s Acid
265 R.Acid
269 H.Acid
273 N-Phenyl-J.Acid
As it is clear from Shade comparison-9 (un-metallized naphthol dyes) almost all of the dyes had
different shades both in 2% and 5% dyed leathers, along with a variation of depth of shades. This
can be attributed to the difference of chromophoric systems in all the dyes.The dyes of β-
naphthol homologues (Schaeffer’s Acid and R. Acid) are lighter and redder. The variation of the
depth can be attributed to the participation of peripheral group’s variation of different naphthols.
The α-naphthol homologue, the dye of H.Acid (1-amino-8-naphthol-3,6-disulphonic acid) and
NPJ (N-Phenyl –J. Acid)(2-aminophenyl-5-naphthol-7-sulfonic Acid)has been found to be much
darker, this can be due to presence of free NH2 and NH groups in these dyes.
153
Shade comparison-10
COMPARISON OF CHROMIUM METALLIZED DYES OF NAPHTHOL SERIES
Dye # Naphthol 2% Shade 5% Shade
258 β-Naphthol
262 Schaeffer’s
Acid
266 R.Acid
270 H.Acid
274 N-Phenyl-
J. Acid
As it is clear from Shade comparison-10 (chromium-metallized naphthol dyes) almost all of the
dyes had bluer shades both in 2% and 5% dyed leathers, along with a variation of depth of
shades as compared to their parent dye-ligands. The dyes of β-naphthol homologues (Schaeffer’s
Acid and R. Acid)are lighter and redder. This can be attributed to the difference of chromophoric
systems in the couplers of all dyes. The variation of the depth can be attributed to the
participation of peripheral group’s variation of difference of naphthol moieties. The dye of
H.Acid (1-amino-8-naphthol-3,6-disulphonic Acid) has been found to be much darker like its
parent dye-ligand. This can be due to the presence of free amino group in it. Similarly the dye
with NPJ (N-Phenyl –J. Acid) (2-aminophenyl-5-naphthol-7-sulfonic Acid) have also been found
to be much darker and bluer as these are α-naphthol homologues.
154
Shade comparison-11
COMPARISON OF IRON METALLIZED DYES OF NAPHTHOL SERIES
Dye # Naphthol 2% Shade 5% Shade
259 β-Naphthol
263 Schaeffer’s Acid
267 R.Acid
271 H.Acid
275 N-Phenyl-
J.Acid
As it is clear from Shade comparison -11 (iron-metallized naphthol dyes) almost all of the dyes
had different shades both in 2% and 5% dyed leathers, along with a variation of depth of shades.
This can be attributed to the difference of chromophoric systems in all dyes. However, it is clear
from shades that this difference is due to the difference of α-naphthol and β-Naphthol
differences. It is clear that α-naphthol homologues (H. Acid and NPJ) have similar dark shades
and β-naphthol homologues (Schaeffer’s Acid and R. Acid) have similar light shades(olive
shades. The variation of the depth can be attributed to the participation of peripheral group’s
variation of difference of naphthol moieties. The dye of H.Acid (1-amino-8-naphthol-3,6-
disulphonic acid) has been found to be much darker, this can be due to the presence of its free
155
amino group. Similarly the dye with NPJ (N-Phenyl–J.Acid) (2-aminophenyl-5-naphthol-7-
sulfonic acid) have been also found to be much darker.
Shade comparison -12
COMPARISON OF COPPER METALIZED DYES OF NAPHTHOL SERIES
Dye # Naphthol 2% Shade 5% Shade
260 β -Naphthol
264 Schaeffer’s Acid
268 R.Acid
272 H. Acid
276 N-Phenyl-J. Acid
Almost all copper-metallized naphthol dyes (Shade comparison-12) had been found to be
different; both in 2% and 5% dyed leathers, along with a variation of depth of shades. This can
be attributed to the difference of chromophoric systems in all these dyes. However, it is clear
from shades that this difference is due to the difference of α-naphthol and β-naphthol differences.
The α-naphthol homologues (H. Acid and NPJ) have similar dark shades and β-naphthol
homologues (Schaeffer’s Acid and R. Acid) have similar light and redder shades like their parent
un-metallized dyes.
The variation of the depth can be attributed to the participation of peripheral group’s variation in
different naphthols. The dye of H.Acid (1-amino-8-naphthol-3,6-disulphonic acid) and NPJ (N-
156
Phenyl-J. Acid) (2-aminophenyl-5-naphthol-7-sulfonicacid) has been found to be much darker,
this can be due to the presence of free NH2 and NH groups in H Acid and NPJ respectively.
4.11 Synthesis of p-Substituted-Phenols, Resorcinol and Bis-Phenol series of dyes.
In this series a total number of 20 dye samples were prepared and for this purpose 3 different
para substituted phenols, namely, p-chlorophenol, p-nitrophenol and phenol-4-suphonicAcid, 2-
nitrophenol-4-suphonic acid, resorcinol and bisphenols were used as couplers. Four dye samples
were prepared with each coupler. The first being un-metallized dye and the three were
chromium, iron and copper complexes respectively. Chromium complexes were of 2:1 type. The
synthetic schemes for the preparation of p-substituted phenols, resorcinol and bisphenol dyes are
presented as Scheme-4.6 and 4.7.
SPMP [1-(4-sulphophenyl)3-methyl-2-pyrazolin-5-one] was nitrosated at 0-5ºC using NaNO2
and HCl as described by Knorr1. The nitroso compound was filtered to remove some terry
material. The clarified nitroso derivative [that usually exists in an oxime form (as indicated by its
FTIR)], was salted out by common salt. It was dried after filtration. Reduction of oxime was
carried at 100-105ºC using Zinc and HCl. The oxime and Zinc were alternatively added in small
portions in boiling HCl solution. The reduction was completed as the solution became colorless.
A small amount of additional zinc dust was also added to prevent aerial oxidation on cooling.
The resultant amine hydrochloride was quenched to -7 ºC. The excessive un-reacted zinc was
removed by filtration.
The amine hydrochloride was diazotized using an aqueous solution of NaNO2 (6.9g dissolved in
250mL of solution) and HCl at -5 to -2ºC to avoid the formation of Rubazoic acid, which is
automatically formed during this reaction with increasing temperature due to oxidizing action of
nitrous acid, formed in situ.
The diazonium salt prepared in this way was coupled with different para substituted phenols,
like, p-Chlorophenol, p-Nitrophenol, phenol-4-suphonic acid, 2-Nitrophenol-4-suphonic acid and
bisphenols (Bisphenol S and Bisphenol A). The coupling was carried out in alkaline medium at
pH 8-9. The synthesis of this diazo has been confirmed from X-ray of its crystal. Coupling in
alkaline medium occurred at ortho position to the hydroxyl groups of phenols and bisphenols as
para position was blocked. The synthesized dyes (18a-g) were precipitated on completion of
157
reaction by reducing the pH of solution to 1.0 with HCl. The filtered dyes were dried and
purified in ethanol. Metallization of these dyes was done by treating their alkaline solution with
FeSO4.7H2O, CuSO4.5H2O and Cr(CH3COO)3 at 65-70oC and 100-105
oC. It took about 4-5h to
complete the metallization as was observed by taking the TLC of reaction mixture in 9:1
chloroform and methanol.
Dyes (19a-u) were precipitated with addition of HCl, filtered and dried in oven at 80oC. These
dyes were again purified from ethanol, dried, weighed and determined the percentage yield.
These unmetallized dyes 18a-g were tridentate ligands which formed complexes with Iron (Fe,
II), Copper (Cu, II) and Cr (III) through 1:1 metal and 2:1 ligand stoichiometric ratio. In case of
Fe2+
and Cu2+
complexes lone pairs of electrons were donated by two oxygen atoms and one
nitrogen atom of the diazo linkage, while the other three coordination numbers of these metals
have been satisfied by three water molecules. The complex formation pattern has been verified
by the UV-visible spectrophotometric studies of these dyes 19a-u.
In case of IR spectra of compounds different functional moieties showed stretching and bending
bands characteristic of the synthesized compounds. The infrared spectra of the synthesized acid
dyes and their metal complexes exhibited absorption peaks due to O-H, Ar-H, C-H, C=O, C=C,
N=N, SO3H, C-O and O-M stretching and bending vibrations at 3399, 3050, 2926, 1550, 1472,
1272, 1164, 1004, 834 and 610 cm-1
as depicted from their FTIR spectra (Figure 4.31). Similarly
other metal complexes have been confirmed from their respective IR spectra.
158
NN
SO3H
H3C
OHNaNO2, HCl
-2 -(-5) oC
NN
SO3H
H3C
OH
N O
Zn + HClN
N
SO3H
H3C
OH
NH3
NaNO2, HCl
25-30 oC
NN
SO3H
H3C
O
N N
OH
R3
R2
12 3 4
17a-d
NaO3S
N
N
CH3
OH
N N
HO
R3
R2
Na2CO3/NaOH
10 -15 oC
Metalization60 -65 oC
OH2OH2
H2O
HO3S
N
N
CH3
O
N N
M+2 O
R3
R2
18a-d
19a-h
R1
R1
R1
17e-g
Na2CO3/NaOH
10 -15 oC
N
N
H3C
HO
NN
N
N
CH3
OH
NN
SO3HHO3S
O
N
N
H3C
O
NN
N
N
CH3
O
NN
O
SO3HHO3S
M+2
M+2
H2OH2O
H2OH2OH2O
H2O
60 -65 oC Metalization
18e-g
19i-n
Cl
17-18a R1=R2=H, R3=Cl, Dye=277,
17-18b R1=R2=H, R3=NO2,Dye=281
17-18c R1=R2=H, R3=SO3H, Dye=285,
17-18d R1=H, R2=NO2, R3=SO3H, Dye=289,
17-18e Ar= Resorcinol, Dye=293,
17-18f Ar= Bis-Phenol S, Dye =297,
17-18g Ar= Bis-Phenol A, Dye= 301
19a R1=R2=H, R3=Cl, M= Fe (II), Dye= 279 19b R1=R2=H, R3=Cl, M= Cu (II), Dye= 280
19c R1=R2=H, R3=NO2, M= Fe (II), Dye= 283 19d R1=R2=H, R3=NO2, M= Cu (II), Dye= 284
19e R1=R2=H, R3=SO3H, M= Fe (II), Dye= 287 19f R1=R2=H, R3=SO3H, M= Cu (II), Dye= 288
19g R1=H, R2=NO2, R3=SO3H, M= Fe (II), Dye= 291 19h R1=H, R2=NO2, R3=SO3H, M= Cu (II), Dye= 292
19i Ar= Resorcinol, M= Fe (II), Dye=295, 19j Ar= Resorcinol, M= Cu (II), Dye=296,
19k Ar= Bis-Phenol S, M= Fe (II), Dye= 299 19l Ar= Bis-Phenol S, M= Cu (II), Dye= 300
19m Ar= Bis-Phenol A, M= Fe (II), Dye= 303 19n Ar= Bis-Phenol A,M= Cu (II), Dye= 304
Ar
OHHO
Ar
HO OH
Ar
Scheme 4.6, Synthesis of ligand acid dyes 18a-g and their Fe (II) and Cu (II) complexes (19a-n,
277-304)
159
NN
SO3H
H3C
OHNaNO2, HCl
-2 -(-5) oC
NN
SO3H
H3C
OH
N O
Zn + HClN
N
SO3H
H3C
OH
NH3
NaNO2, HCl
25-30 oC
NN
SO3H
H3C
O
N N
OH
R3
R2
12 3 4
17a-d
NaO3S
N
N
CH3
OH
N N
HO
R3
R2
Na2CO3/NaOH
10 -15 oC
Metalization60 -65 oC
HO3S
N
N
CH3
O
N N
Cr+3O
R3
R2
18a-dR1
R1
R1
17e-gNa2CO3/NaOH
10 -15 oC
N
N
H3C
HO
NN
N
N
CH3
OH
NN
SO3HHO3S
O
N
N
H3C
O
NNN
N
CH3
O
NN
O
SO3HHO3S
Cr+3Cr+3
60 -65 oC Metalization
18e-g
Cl
17-18a R1=R2=H, R3=Cl, Dye=277,
17-18b R1=R2=H, R3=NO2,Dye=281
17-18c R1=R2=H, R3=SO3H, Dye=285,
17-18d R1=H, R2=NO2, R3=SO3H, Dye=289,
17-18e Ar= Resorcinol, ,Dye=293,
17-18f Ar= Bis-Phenol S, Dye=297,
17-18g Ar= Bis-Phenol A, Dye=301,
19o R1=R2=H, R3=Cl, Dye= 278 19p R1=R2=H, R3=Cl, Dye= 282
19q R1=R2=H, R3=NO2, Dye= 286 19r R1=R2=H, R3=NO2, Dye= 290
19s Ar= Resorcinol, Dye=294, 19t Ar= Bis-Phenol S, Dye=298,
19u Ar= Bis-Phenol A, Dye=302
HO3S
N
N
CH3
O
N N
O
R3
R2
R1
O
N
N
CH3
O
NN N
N
H3C
O
NN
O
HO3S
SO3H
19o-r
19s-u
OHHO
Ar
Ar
Ar
HO OH
Ar
Scheme 4.7, Synthesis of ligand acid dyes 18a-g and their Cr (III) complexes (19o-u, 277-302)
160
Figure 4.31, FTIR spectrum of Iron complex of dye 18b (281).
1H-NMR and
13C-NMR spectra were taken for ligand dyes which showed characteristic signals
for different protons and carbons at different positions which evidenced the synthesis of dyes. In
case of compounds 18b (281) signal for hydroxyl group was absent due to exchangeable proton
with DMSO. The doublet signal of mutually coupled set of four protons of phenyl group
substituted with sulfonic group at present 7.95 and 7.68 ppm having coupling constant
respectively signals 8.6 Hz. The multiplet signal for one proton of aromatic ring of coupling
moiety is present at 7.83-7.90 ppm while the same ring bearing another single proton shows
signal at 8.07 ppm with coupling constant 2.35 Hz which evidenced the meta relationship with
another proton at the same ring. The methyl group present at pyrazolone ring exhibited singlet
signal at 2.20 ppm (Figure 4.32).
In 13
C-NMR spectrum the signal for methyl group is present at 12.14 ppm. There are ten signals
in the range 117.06-158.00 ppm for different carbon nuclei in the compound (Figure 4.33). In
this way other ligand acid dyes were confirmed from their respective 1H-NMR and
13C-NMR
spectra. When the 1H-NMR spectra of metal complex dyes were conducted they showed very
broad and distorted signals due to paramagnetic nature of metals used for complexation and the
so the NMR study of complexes was not fruitful for structure elucidation but in other words the
distorted broad signals proved the complexation when the 1H-NMR of ligands acid dyes and
complexes were compared.
161
Figure 4.32, 1H-NMR spectrum of ligand acid dye 18b (281).
Figure 4.33, 13
C-NMR spectrum of ligand acid dye 18b (281).
4.11.1 p-Chlorophenol dyes.
Four dye samples were prepared with p-chlorophenol. The first dye being un-metallized one and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was of 2:1 type. The detailed physical properties of p-chlorophenol dyes are given in Table-4.25.
162
Table-4.25; Physical properties of dyes 277-280
The UV-Visible data presented in Table-4.25 are supported by UV-Visible Spectra-20 (Figure
4.34).The un-metallized dye 277 (18a) was an orange dye with λmax 460 nm and absorbance 2.3.
Its metallization with chromium had changed its color to yellowish red with λmax 470 nm and
absorbance 2.0 (dye 278), showing a bathochromic shift of 10 nm with a hypochromic effect of
0.3. On the other hand metallization of dye 277 (18a) with iron produced an olive brown dye
(dye 279) with λmax 440 nm and absorbance 1.1, showing a hypsochromic shift of 30 nm with a
hypochromic effect of 1.2.
While metallization of dye 277 (18a) with copper resulted in the formation of a reddish violet
dye (dye 280) with λmax 490 nm and absorbance 1.3. It showed a bathochromic shift of 30 nm
with a hypochromic effect of 1.0.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
277 HO3S
N
N
CH3
OH
N N
OH
Cl
C16H13Cl
N4O5S
Orange/
Reddish
Orange
360/0.9,
460/2.3 Water
278
HO3S
N
N
CH3
O
N N
O
Cl
HO3S
N
N
CH3
O
N N
O
Cl
Cr-
H+
C32H23Cl2
CrN8O10S2
Maroon/
Yellowish
Red
360/0.9,
470/2.0 Water
279
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
Fe O
Cl
C16H17Cl
FeN4O8S
Olive/
Olive
Brown
360/1.8,
440/1.1 Water
280
OH2
HO3S
N
N
CH3
O
N N
Cu-
O
Cl
C16H13Cl
CuN4O6S
Tan/
Reddish
Violet
360/1.1,
490/1.3 Water
163
Figure 4.34; UV-Visible Spectra-20 of dyes 277-280 (648 -umd = dye 277,
6648-Cr = dye 278, 6648 -Fe = dye 279 and 6648 - Cu = dye 280).
4.11.2 p-Nitrophenol dyes.
Four dye samples were prepared with p-nitrophenol. The first dye was un-metallized one and the
other three were chromium, iron and copper complexes respectively. Chromium complex was of
2:1type. The detailed properties of p-nitrophenol dyes are given in Table-4.26.
164
Table-4.26; Physical properties of dyes 281-284
The UV-Visible data presented in Table-4.26 are supported by UV-Visible Spectra-21 (Figure
4.34). The un-metallized dye 281 (18b) was an orange dye with λmax 480 nm and absorbance 3.1.
Its metallization with chromium had not changed its color but λmax to 470 nm and absorbance 1.8
(dye 282), showing a hypsochromic shift of 10 nm with a hypochromic effect of 1.3.
On the other hand metallization of dye 281(18b) with iron produced a yellowish brown dye (dye
283) with λmax 440 nm and absorbance 1.3, that showed a hypsochromic shift of 40 nm with a
hyperchromic effect of 1.8. While metallization of dye 281(18b) with copper resulted in the
formation of a reddish yellow dye (19d,dye 284) with λmax 460 nm and absorbance 2.3 , showing
a hypsochromic shift of 20 nm with a hypochromic effect of 0.8.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
281 HO3S
N
N
CH3
OH
N N
OH
NO2
C16H13N5
O7S
Dark
Brown /
Reddish
Orange
480/3.1 Water
282
HO3S
N
N
CH3
O
N N
O
NO2
HO3S
N
N
CH3
O
N N
O
NO2
Cr-
H+
C32H23Cr
N10O14S2
Dark
Brown/
Reddish
Orange
470/1.8 Water
283
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
Fe O
NO2
C16H17Fe
N5O10S
Gray/
Yellowish
Brown
440/1.3 Water
284
OH2
HO3S
N
N
CH3
O
N N
Cu-
O
Cl
C16H13Cu
N5O8S
Tan/
Reddish
Yellow
460/2.3 Water
165
Figure 4.35; UV-Visible Spectra-21 of dyes 281-284 (4448 -umd = dye 281,
4448-Cr = dye 282, 4448 -Fe = dye 283 and 4448 - Cu = dye 284)
4.11.3 Phenol-4-sulphonic acid dyes.
Four dyes were prepared with phenol-4-sulphonic acid. The first dye was un-metallized one and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was 2:1 type. The detailed properties of phenol-4-sulphonic acid dyes are given in Table-4.27.
166
Table-4.27, Physical properties of dyes 285-288
The UV-Visible data presented in Table-4.27 are supported by UV-Visible Spectra-22 (Figure
4.25). The un-metalized dye 285 (18c) was a yellowish orange dye with λmax 460 nm and
absorbance 2.7. Its metallization with chromium had changed its color to reddish orange with
λmax 480 nm and absorbance 1.0 (dye 286, 19q). It showed a bathochromic shift of 20 nm with a
hypochromic effect of 1.7.
On the other hand metallization of dye 285 (18c) with iron produced a yellowish brown dye (dye
287, 19e) with λmax 430 nm and absorbance 1.58, showing a hypsochromic shift of 30 nm with a
hypochromic effect of 1.12. While metallization of dye 285 (18c) with copper resulted in the
formation of a reddish orange dye (dye 288, 19f) with λmax 460 nm and absorbance 2.05,
showing a hypochromic effect of 0.65.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubility
285 HO3S
N
N
CH3
OH
N N
OH
SO3H
C16H14N4
O8S2
Orange/
Yellowish
Orange
460/2.7 Water
286
HO3S
N
N
CH3
O
N N
O
SO3H
HO3S
N
N
CH3
O
N N
O
SO3H
Cr-
H+
C32H25Cr
N8O16S4
Tan/
Reddish
Orange
480/1.0 Water
287
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
Fe O
SO3H
C16H18Fe
N4O11S2
Olive
Brown/
Yellowish
Brown
430/1.58 Water
288
OH2
HO3S
N
N
CH3
O
N N
Cu-
O
SO3H
C16H14Cu
N4O9S2
Brown/
Yellowish
Orange
460/2.05 Water
167
Figure 4.36; UV-Visible Spectra-22 of dyes 285-288(7648-umd = dye 285,
7648-Cr = dye 286, 7648 -Fe = dye 287 and 7648 - Cu = dye 288)
4.11.4 2-Nitro-4-sulphophenol dyes.
Four dyes were prepared with 2-nitro-4-sulphophenol. The first dye was un-metallized one and
the other three were chromium, iron and copper complexes respectively. Chromium complex
was 2:1 type. The detailed properties of 2-nitro-4-sulphophenol dyes are given in Table-4.28.
168
Table-4.28; Physical properties of dyes 289-292
The UV-Visible data presented in Table-4.28 are supported by UV-Visible Spectra-23 (Figure
4.36). The un-metallized dye 289 (18d) was a reddish orange dye with λmax 520 nm and
absorbance 3.3. Its metallization with chromium had changed its λmax to 490 nm and absorbance
5.7 (dye 290, 19r), showing a hypsochromic shift of 30 nm with a hyperchromic effect of 2.4.On
the other hand metallization of dye 289 (18d) with iron produced a yellowish brown dye (dye
291) with λmax 470 nm and absorbance 3.4, showing a hypsochromic shift of 50 nm with a
hyperchromic effect of 0.1.
While metallization of dye 289 (18d) with copper resulted in the formation of a reddish brown
dye 292 (19h) with λmax 500 nm and absorbance 3.0. It showed a hypsochromic shift of 20 nm
with a hypochromic effect of 0.3.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax(nm)/
Absorba-
nce
Solubiliity
289 HO3S
N
N
CH3
OH
N N
OH NO2
SO3H
C16H13N5
O10S2
Orange/
Reddish
Orange
520/3.3 Water
290
HO3S
N
N
CH3
O
N N
O
HO3S
N
N
CH3
O
N N
OCr-
NO2
SO3H
NO2
SO3H
H+
C32H23Cr
N10O20S4
Brown/
Reddish
Orange
490/5.7 Water
291
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
Fe O NO2
SO3H
C16H17Fe
N5O13S2
Gray/
Yellowish
Orange
470/3.4 Water
292
OH2
HO3S
N
N
CH3
O
N N
Cu-
O NO2
SO3H
C16H13Cu
N5O11S2
Tan/
Reddish
Brown
500/3.0 Water
169
Figure 4.37; UV-Visible Spectra-23 of dyes 289-292(11948 -umd = dye 289,
11948-Cr = dye 290, 11948 -Fe = dye 291 and 11948 - Cu = dye 292)
4.11.5 Disazo Resorcinol Dyes.
Four disazo dyes were prepared with resorcinol. The first dye was un-metallized one and the
other three were chromium, iron and copper complexes respectively. Chromium complex was of
bis 2:1 type. The schemes for the preparation of resorcinol disazo dyes had already been given as
schemes 4.6 and 4.7. The detailed properties of disazo resorcinol dyes are given in Table-4.29
170
Table-4.29 Physical properties of dyes 293-296
Here Ar – represents benzene-4-sulphonic acid.
The UV-Visible data presented in Table-4.29 are supported by UV-Visible Spectra-24 (Figure
4.39). The un-metallized dye 293(18e) was a reddish orange dye with λmax 460 nm and
absorbance 1.03. Its metallization with chromium had changed its λmax to 500 nm and absorbance
0.36 (dye 294, 19s). It showed a bathochromic shift of 40 nm with a hypochromic effect of 0.67.
On the other hand metallization of dye 293 (18e) with iron produced a yellowish orange dye 295
(19i) with λmax 440 nm and absorbance 0.45, showing a hpsochromic shift of 20 nm with a
hypochromic effect of 0.58.
While metallization of dye 293 (18e) with copper resulted in the formation of a yellowish brown
dye 296 (19j) with λmax 480 nm and absorbance 0.3, showing a bathochromic shift of 20 nm with
a hyperchromic effect of 0.73.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
293 Ar-
N
N
CH3
OH
N N
OH OH
Ar-
N
N
CH3
OH
NN
C26H22N8
O10S2
Orange/
Reddish
Orange
460/1.03 Water
294
Ar-
N
N
CH3
O
N N
O O
Ar-
N
N
CH3
O
NN
Ar-
N
N
CH3
O
N N
O O
Ar-
N
N
CH3
O
NN
Cr-
Cr-
H+
2
C52H37Cr2
N16O20S4
Brown/
Reddish
Orange
360/0.5,
500/0.36 Water
295
OH2
Ar-
N
N
CH3
O
N N
O O
Ar-
N
N
CH3
O
NN
OH2OH2
OH2
Fe
OH2OH2
Fe
C26H30Fe2
N8O16S2
Brown/
Yellowish
Orange
440/0.45 Water
296
OH2
Ar-
N
N
CH3
O
N N
O O
Ar-
N
N
CH3
O
NN
OH2
Cu-Cu
-
C26H22Cu2
N8O12S2
Tan/
Yellowish
Brown
480/0.31 Water
171
Figure 4.38; UV-Visible Spectra-24 of dyes 293-296 (4841 umd = dye 293,
4841-Cr = dye 294, 4841-Fe = dye 295 and 4841-Cu = dye 296)
4.12 The Dyeing Properties of p-Substituted Phenols and Resorcinol Dyes
The dyeing properties of p-substituted phenols and resorcinol dyes have been found to be very
attractive. Almost all properties have been found to be of very high value (4-5). However,
chromium complexes have found to be the best ones and un-metallized dye-ligands with low
values as per expectation due to the presence of free hydroxyl groups. The dyeing properties of
these dyes are given in Table-4.30.
172
Table-4.30; The Dyeing Properties of p-Substituted Phenols and Resorcinol Dyes.
Dye
#
2%Shade on
Leather
5%Shade on
Leather Penetration
Washing
Fastness
Light
Fastness
Perspiration
Fastness
277 Yellowish Orange Reddish Orange 2 2-3 2-3 3-4
278 Reddish Orange Maroon 4 3-4 4-5 4-5
279 Olive Dark Olive 5 4-5 5 5
280 Yellowish Orange Reddish Brown 3 3-4 3-4 4-5
281 Orange Yellowish Orange 2 2-3 2-3 3-4
282 Reddish Orange Tan 4 3-4 4-5 4-5
283 Olive Dark Olive 5 4-5 5 5
284 Yellowish Orange Yellowish Brown 3 3-4 3-4 4-5
285 Yellowish Orange Dark Yellowish
Orange 3 3-4 2-3 3-4
286 Light yellowish Red Dark Yellowish
Red 4 3-4 4-5 4-5
287 Light Olive Dark Olive 5 4-5 5 5
288 Light Yellowish
Orange Yellowish Orange 4 3-4 3-4 4-5
289 Tan Yellowish Brown 3 3-4 3-4 3-4
290 Pink Reddish Tan 4 3-4 4-5 4-5
291 Olive Brown Dark Olive 5 4-5 5 5
292 Yellowish Orange Reddish Orange 3 3-4 3-4 4-5
293 Light Brown Dark Reddish Brown 2 2-3 2-3 3-4
294 Light Tea Pink Tea pink 4 3-4 4-5 4-5
295 Olive brown Brown 5 4-5 5 5
296 Beige Tan 3 3-4 3-4 4-5
The data given in Table -4.30 are supported by Shade-Card-4a and b
173
Shade Card-4, part-a
174
Shade Card-4, part-b
A mutual comparison of shades of p-substituted phenols and resorcinol dyes is presented in
Shade Comparison 13-16, for un-metallized, chromium, iron and copper complexes
respectively.
175
Shade comparison-13
Comparison of Un-Metallized Dyes of p-Substituted Phenols and Resorcinol Dyes
Dye # Phenol 2% Shade 5% Shade
277 p-Chloro-Phenol
281 p-Nitro Phenol
285 p-Sulpho-Phenol
289 o-Nitro-p-Sulpho-Phenol
293 Resorcinol
Almost all the un-metallized p-substituted phenols and resorcinol dyes (Shade comparison-13)
have been found to be different; both in 2% and 5% dyed leathers, along with a variation of
depth of shades. This can be attributed to the difference of chromophoric systems in all these
dyes. However, it is clear from shades that this difference is due to the difference of p-
substituents in different phenols. All of the phenol homologue shades were dark and redder
except p-sulphophenol. The variation of the depth can be attributed to the participation of
peripheral group’s variation in different phenols. Resorcinol dyes were disazo ones; hence these
were clearly different from the other phenolic ones.
176
Shade comparison-14
Comparison of Chromium Metalliezd Dyes of p-Substituted Phenols and Resorcinol.
Dye # Phenol 2% Shade 5% Shade
278 p-Chloro-Phenol
282 p-Nitro Phenol
286 p-Sulpho-Phenol
290 o-Nitro-p-Sulpho-
Phenol
294 Resorcinol
All chromium-metallized p-substituted phenols and resorcinol dyes (Shade comparison-14)
have been found to be different; both in 2% and 5% dyed leathers, along with a variation of
depth of shades. This can be attributed to the difference of chromophoric systems in all such
dyes. However, it is clear from shades that this difference is due to the difference of p-substitu-
ents in different phenols. All of the phenol homologues had dark and redder shades except p-sul-
phophenol. The variation of the depth can be attributed to the participation of peripheral groups
variation in different phenols. Both nitrophenols had similar shades with yellowish red tone.
Resorcinol dyes are disazo ones, hence these are clearly different from other phenolic ones as
these are bis-metal complexes.
177
Shade comparison-15
Comparison of Iron Metaliezd Dyes of p-Substituted Phenols and Resorcinol.
Dye # Phenol 2% Shade 5% Shade
279 p-Chloro-Phenol
283 p-Nitro Phenol
287 p-Sulpho-Phenol
291 o-Nitro-p-Sulpho-
Phenol
295 Resorcinol
Almost all iron-metalized phenol and resorcinol dyes (Shade comparison-15) are found to be
similar (olive); both in 2% and 5% dyed leathers, along with a variation of depth of shades.
However, it is clear from shades that the depth difference is due to the difference of p-
substituents in different phenols. All the phenol homologues had dark and redder shades except
p-sulphophenol. Both nitro phenols had similar shades with yellowish tone. Resorcinol dyes are
disazo ones hence, these are clearly different from phenolic ones as these being Bis-metal
complexes.
178
Shade comparison-16
Comparison of Copper Metaliezd p-Substituted Phenols and Resorcinol Dyes.
Dye # Phenol 2% Shade 5% Shade
280 p-Chloro-Phenol
284 p-Nitro Phenol
288 p-Sulpho-Phenol
292 o-Nitro-p-Sulpho
Phenol
296 Resorcinol
Almost all copper-metalized phenolic and resorcinol dyes (Shade comparison-16) have been
found to be different; both in 2% and 5% dyed leathers, along with a variation of depth of
shades. This can be attributed to the difference of chromophoric systems in all these dyes.
However, it is clear from shades that this difference is due to the difference of p-substituents in
different phenols. All of the phenol homologues had dark and redder shades except p-sulph-
ophenol. Both nitro phenols had similar shades with yellowish red tone. Resorcinol dyes were
disazo dyes, hence these were clearly different from phenolic ones as these were bis-metal
complexes.
4.13 Synthesis of Bisphenol Dyes.
In this series a total number of 8 dyes were prepared and for this purpose two different
bisphenol-S (BPS) and bisphenol-A (BPA) were used as couplers.
179
4.13.1 Bisphenol-S Dyes.
Four dyes were prepared with bisphenol-S (4,4־-dihydroxy biphenyl sulfone). The first dye was
un-metallized one and the three were bis chromium, iron and copper complexes respectively.
Chromium complex was 2:1 type. The synthesis of bisphenol dyes was given in Schemes-4.6
and 4.7. The physical properties of bisphenol-S are presented in Table-4.31.
Table-4.31; Physical properties of dyes 297-300
Here Ar –
represents phenyl-4-sulphonic acid
The UV-Visible data presented inTable-4.31 are supported by UV-Visible Spectra-25 (Figure
4.40).
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
297 OH
N
N
CH3
OH
NN Ar-
N
N
CH3
OH
N N
OH
SO
Ar-
O
C32H26N8
O12S3
Orange/
Reddish
Orange
420/2.3 Water
298 O
N
N
CH3
O
N NAr-
N
N
CH3
O
NN
O
SO
Ar-
O
O
N
N
CH3
O
NN Ar-
N
N
CH3
O
N N
O
SO
Ar-
O
Cr-
Cr-
H+
2
C64H46Cr2
N16O24S6
Beige/
Yellowish
Orange
410/2.5 Water
299 OH2
OH2
OH2
OH2OH2OH2
O
N
N
CH3
O
NN Ar-
N
N
CH3
O
N N
O
SO
Ar-
O
Fe
Fe
C32H34Fe2
N8O18S3
Brown/
Reddish
Brown
360/2.8,
410/3.6 Water
300 OH2
OH2
O
N
N
CH3
O
NNN
N
CH3
O
N N
O
SO
O
Cu-
Cu-Ar
-
Ar-
C32H29Cu2
N8O14S3
Tan/
Yellow 370/1.6 Water
180
Figure 4.39; UV-Visible Spectra-25 of dyes 297-300 (4826-umd = dye 297,
4826-Cr = dye 298, 4826-Fe = dye 299 and 4826-Cu = dye 300)
The un-metallized dye 297 was a reddish orange dye with λmax 420 nm and absorbance 2.3. Its
metallization with chromium had changed its color to yellowish orange with λmax 410 nm and
absorbance 2.5 (dye 298), showing a hypsochromic shift of 10 nm with a hyperchromic effect of
0.5.On the other hand metallization of dye 297 (18f) with iron produced a reddish brown dye
(dye 299,19k) with λmax 410 nm and absorbance 3.6, showing a hypsochromic shift of 10 nm
with a hyperchromic effect of 1.1.
While metallization of dye 297 (18f) with copper resulted in the formation of a yellow dye (dye
300,19l) with λmax 370 nm and absorbance 1.6, showing a hypsochromic shift of 50 nm with a
hyperchromic effect of 0.7.
181
4.13.2 Bisphenol-A Dyes.
Four disazo dyes were prepared with Bisphenol-A (4, 4־-dihydroxy biphenyl propane). The first
dye was un-metallized one and the other three were chromium, iron and copper bis-metal
complexes respectively. Chromium complex was of 2:1 type. The detailed properties of disazo
BPA dyes are given in Table-4.32.
Table-4.32 Physical properties of dyes 301-304
The UV-Visible data presented in Table-4.32 are supported by UV-Visible Spectra-26 (Figure
4.41). The un-metallized dye 301(18g) was a yellowish orange dye with λmax 450 nm and
absorbance 2.7. Its metallization with chromium had changed its color to yellowish orange with
λmax 480 nm and absorbance 1.5 (dye 302, 19u). It showed a bathochromic shift of 30 nm with a
hypochromic effect of 1.2. On the other hand metallization of dye 301 (18g) with iron produced
a reddish brown dye 303 (19m) with λmax 440 nm and absorbance 2.3, showing a hypsochromic
shift of 10 nm with a hyochromic effect of 0.4.
Dye # Dye Structure
Molecular
formula
(Calc.)
Powder/
Solution
Color
λmax (nm)/
Absorba-
nce
Solubility
301 OH
N
N
CH3
OH
NN Ar-
N
N
CH3
OH
N N
OH
Ar-
CH3CH3
C35H32N8
O10S2
Brown/
Yellowish
Orange
450/2.7 Water
302 O
N
N
CH3
O
N NAr-
N
N
CH3
O
NN
O
Ar-
CH3CH3
O
N
N
CH3
O
NN Ar-
N
N
CH3
O
N N
O
Ar-
CH3CH3
Cr-
Cr-
H+
2
C70H58Cr2
N16O20S4
Tan/
Reddish
Orange
360/1.4,
480/1.5 Water
303 O
N
N
CH3
O
NNN
N
CH3
O
N N
O
CH3CH3
OH2
OH2OH2
Fe
OH2OH2
OH2
Fe
Ar-
Ar-
C35H40Fe2
N8O16S2
Grey/
Reddish
brown
370/1.7,
440/2.3 Water
304 OH2
OH2
O
N
N
CH3
O
NN Ar-
N
N
CH3
O
N N
O
Ar-
Cu-
Cu-
CH3CH3
C35H32Cu2
N8O12S2
Dark
Brown /
Yellowish
Orange
450/1.5 Water
182
While metallization of dye (dye 301,18g) with copper resulted in the formation of a yellowish
orange dye (dye 304,19n) with same λmax 450 nm and absorbance 1.5, showing a hypochromic
effect of 0.2.
Figure 4.40; UV-Visible Spectra-26 of dyes 301-304 (48BPA-umd = dye 301,
48BPA-Cr = dye 302, 48BPA-Fe = dye 303 and 48BPA-Cu = dye 304)
4.14 The Dyeing Properties of Bis-Phenol Dyes
The dyeing properties of bisphenols dyes have been found to be very good. Almost all properties
have been found to be of very high value (4-5).The dyes with bisphenol-A has been found to be
much darker as compared to the dyes of bisphenol-S. This can be attributed to the
n→п*electronic transitions occurring in sulphone group of Bisphenol-S. However, chromium
and copper complexes were found to be the best ones and un-metallized dye-ligands with low
values as per our expectation due to the presence of free hydroxyl groups. The dyeing properties
of these dyes are presented in Table -4.33.
183
Table-4.33; Dyeing Properties of Bis-Phenol Dyes
The data presented in Table-4.33 are supported by Shade Card-5.
Dye
#
Shade on
Leather
5%Shade on
Leather Penetration
Washing
Fastness
Light
Fastness
Perspiration
Fastness
297 Greenish Beige Reddish Beige 2 2-3 2-3 3-4
298 Beige Dark Beige 5 4-5 4-5 4-5
299 Beige Dark Reddish
Beige 4 3-4 4-5 4-5
300 Greenish Beige Reddish Beige 5 4-5 5 5
301 Golden Yellow Yellowish Orange 3 3-4 3-4 4-5
302 Reddish Brown Maroon 2 2-3 2-3 3-4
303 Olive Yellowish Brown 4 3-4 4-5 4-5
204 Yellowish
Orange Reddish orange 5 4-5 5 5
184
Shade Card-5.
A mutual comparison of shades of bis-phenol dyes is presented in Shade Comparisons 17-20,
for un-metallized dyes, chromium, iron and copper complexes respectively.
185
Shade Comparison -17
COMPARISON OF UN-METALLIZED BISPHENOLS DYES
Dye # Bisphenol 2% Shade 5% Shade
297 Bisphenol-S
301 Bisphenol-A
As it is clear from Shade-Comparison-17, among the un-metallized Bisphenol dyes, the dye
with Bisphenol-A had a high color value while Bisphenol-S dye gave a low color yield on
leather. This difference can be attributed to the participation of sulphone group present in
Bisphenol-S.
Shade Comparison-18
COMPARISON OF CHROMIUM METALLIZED BIS-PHENOLS DYES.
Dye # Bisphenol 2% Shade 5% Shade
298 Bisphenol-S
302 Bisphenol-A
It is very interesting that chromium metallized bisphenol dyes had greater color value than their
parent un-metallized bisphenol dyes (Shade Comparison-18), The dye with bisphenol-A had a
high color value while bisphenol-S dye gave a lighter and low color yield on leather along with
much redder effect. This difference can be attributed to the participation of sulphone group in
Bisphenol-S.
186
Shade Comparison-19
COMPARISON OF IRON METALLIZED BIS-PHENOL DYES.
Dye # Bisphenol 2% Shade 5% Shade
299 Bisphenol-S
303 Bisphenol-A
It is clear from Shade Comparison-19 that iron metalized bisphenol dyes had greater color
value than their parent un-metallized bisphenol dyes. These dyes are much greener as per our
expectation. The iron dye with bisphenol-S had a low color value while bisphenol-A dye gave a
darker and high color yield on leather along with a much redder effect. This difference can be
attributed to the participation of sulphone group in bisphenol-S.
Shade Comparison-20
COMPARISON OF COPPER METALLIZED BIS-PHENOLS DYES.
Dye # Bisphenol 2% Shade 5% Shade
300 Bisphenol-S
304 Bisphenol-A
Shade Comparison-20 shows that copper metallized bisphenol dyes had greater color value than
their parent un-metalized bisphenol dyes. These dyes are much redder as per our expectation.
The copper dye with bisphenol-A had a high color value while bisphenol-S dye gave a lighter
187
and low color yield on leather along with a much redder effect. This difference can be attributed
to the participation of sulphone group in bisphenol-S.
4.15 Comparison of Shades of Present Work Dyes With National and International
Standards.
This part of my research work is related to the comparison of shades of the dyed leather swatches
with shades of national and international standards. These include two types of matchings which
are , comparison with pantone matching system and comparison with well known leather dyes.
4.15 A- Comparison with Pantone Matching System.
This comparison included matching of our 2% and 5% dyed leather swatch shades with Pantone
Matching System (PMS)215
numbers. The results are presented in Tables-4.34-4.38 for each
series of dyes with their relevant matching PMS numbers.
Table-4.34 Comparison of the naphthol-AS dyes shades with PMS numbers.
Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
Of the dye Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye
201 488 489 202 501 515
203 4525 465 204 692 694
205 1525 154 206 1535 1545
207 464 462 208 1935 201
209 1605 160 210 1685 1815
211 168 175 212 176 202
213 187 730 214 696 697
215 4495 463 216 194 195
217 692 693 218 696 704
219 140 1265 220 1805 1815
221 691 693 222 182 183
223 4525 4515 224 488 489
225 480 723 226 187 188
227 455 4485 228 1767 1765
188
Table-4.35; Comparison of the pyrazolone-pyrazolone dyes shades with PMS numbers.
Table-4.36; Comparison of the naphthol dyes shades with PMS numbers.
Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye
257 1625 157 258 1815 168
259 1265 159 260 158 174
261 488 161 262 672 1955
263 111 163 264 163 167
265 182 165 266 217 204
267 5875 167 268 489 487
269 410 169 270 409 411
271 408 171 272 431 425
273 209 173 274 257 229
275 161 175 276 409 411
Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye Dye #
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye
229 5875 159 230 1205 139
231 581 5835 232 602 617
233 698 718 234 726 167
235 614 617 236 461 124
237 135 1505 238 143 144
239 155 1255 240 1205 155
241 141 1525 242 110 124
243 1265 1255 244 3975 399
245 141 167 246 1205 146
247 4515 465 248 611 125
249 124 1525 250 139 154
251 133 161 252 152 612
253 607 4515 254 607 602
255 5875 5855 256 587 393
189
Table-4.37 Comparison of p-substituted phenol & resorcinol dyes shades with PMS numbers.
Dye#
PMS # for
2%Shade
of the dye
PMS # for
5%Shade
of the dye Dye#
PMS # for
2% Shade
of the dye
PMS # for
5% Shade
of the dye
277 157 1595 278 717 168
279 455 4485 280 157 1675
281 157 150 282 804 180
283 1255 4485 284 143 1525
285 148 142 286 163 164
287 155 157 288 600 145
289 486 167 290 1625 159
291 146 147 292 153 471 2x
293 154 1685 294 435 437
295 4515 1265 296 Cool Grey-2 479
Table-4.38 Comparison of the bisphenol dyes shades with PMS numbers.
Dye #
PMS # for
2%Shade
of the dye
PMS#for,5%
Shade
of the dye
Dye#
PMS # for
2%Shade
of the dye
PMS # for
5%Shade
of the dye
297 155 1205 298 607 458
299 5875 5855 300 427 Warm Grey-2
301 157 716 302 173 174
303 456 146 304 157 167
4.15 B- Comparison with well known Leather Dyes.
The comparison of the synthesized dyes with famous leather dyes manufacturers like Clariant
Dyes216
(Melioderm Dyes/Derma Dyes), Chika Dyes217
(Dermacron Dyes), Colortech dyes218
and
a local leather dye manufacturer Sardar Dyes219
(Leatherol Dyes) has been attempted. It is a
matter of interest to mention here that the dyes of above mentioned companies are mixtures of
several dyes (usually 3 to 5 components mixture). The requisite dyes have been formulated either
in very high or low ratios to get a typical/desired shade. The mixing ratio of a three component
dye may be very high as 45:30:25 or as low as 95:4:1. The dyes used in very small ratio are
usually termed toners. However dyes obtained during the present work were single components.
Several of these have exactly the same shade while others are nearest to the dyes of the above
190
mentioned manufacturers. However the new dyes may also be easily formulated to get the
desired shades. A few of these are presented in Table-4.39 and 4.40.
Table-4.39 Comparison of my dyes with well known National & International leather dyes.
Sr.# Dye # Nearest International Dye Nearest Local Dye
1
203,223,231,
232,240,247,
252,253,254,
255,268,268,
297,299,300
MeliodermHFBeigeDp,
Dermacron Beige 2401,
Dermacron Beige ET,
Dermacron Beige EY,
Dermacron Beige KR,
Colortech Beige ET
Leatherol Beige 2401
2
229,230,236,
237,241,242,
249,250,254,
261,281,284,
285,288
Melioderm Yellow GLp,
Dermacron FastYellowRL,
Dermacron Fast YellowGL,
Dermacron FastYellow4R ,
Colortech Yellow GR
Leatherol Yellow 2F
3 211,,219,227,
250,251,283,
303
Melioderm Brown 2GLp,
Dermacron Brown HGT,
Dermacron Brown J,
Dermacron Brown RD,
Colortech Brown NG
Leatherol Brown 2G
4
205,209,220,
237,241,249,
260,261,264,
286,292,293,
304
Melioderm Brown HGTp,
Dermacron Brown HNR,
Dermacron Brown NR,
Dermacron Brown EB,
Colortech Brown NK
Leatherol Brown HGP
5
206,207,210,
215,216,219,
227,258,259,
269,271,272,
273,275,276,
278,279,282,
283,291,295
Melioderm Brown HF,
Melioderm Deep Brown Fp,
Dermacron Brown HRS,
Dermacron Brown HG,
Dermacron Brown FBT,
Dermacron Brown SRH/C,
Colortech Brown DG
Colortech Brown SG
Leatherol Brown 1288,
Leatherol Brown 1289
6
203,215,227,
235,243,255,
259,263,267,
272,279,287,
303
Melioderm Olive GBp,
Melioderm Green HFp,
Dermacron Olive Brown K,
Dermacron Olive Brown GB,
Dermacron Brown HGT,
Colortech Olive Brown GB
Leatherol Olive 2402
7
206,210,214,
216,226,258,
277,278,293,
202
Melioderm Bordeaux Vp,
Dermacron Bordeaux NB,
Dermacron Bodeaux R,
Dermacron Brown B2C,
Colortech Red E
Leatherol Bordeaux 2430
191
Table-4.40 Comparison of my dyes with well known National & International leather dyes.
Sr.# Dye # Nearest International Dye Nearest Local Dye
1 206,214,218,
226,262,266,
274
Derma Violet 2B,
Derma Violet 3B,
Dermacron Violet 4BS,
Colortech Violet 4BN
Leatherol Violet 3B
2 202,214,222,
226,228,262,
274,302
Derma Violet 6677,
Dermacron Violet 3R,
Dermacron Violet L,
Colortech Violet RB
Leatherol Violet 3R
3
204,205,209,
213,219,237,
238,242,245,
246,250,261,
264,268,281,
284,292,301,
304
Melioderm Orange 2GLp,
Dermacron Fast Orange 2GL,
Dermacron Fast Orange TGL,
Dermacron Fast Orange G,
Colortech Orange 2G
Leatherol Orange 2G
4
237,241,249,
261,264,282,
286,289,290,
292,201,304
Derma Orange RSN,
Dermacron Orange GS,
Dermacron Orange PR,
Dermacron Orange RL,
Coloetech Orange GS
Leatherol Orange RSN
5
208,212,216,
233,257,261,
264,281,282,
286,289,290,
292,201,302,
304
Derma Red 2201,
Melioderm Red HF Gp,
Dermacron Red HF,
Dermacron Red RSR,
Dermacron Red 2R,
Colortech Red NG
Leatherol Red 2201
6 261,264,282,
286,289,290,
292,304
Melioderm Brilliant Red MFp,
Dermacron Scarlet GL,
Dermacron Scarlet GLS,
Colortech Red EN
Leatherol Scarlet GLS
7 269,270,272,
276
Melioderm Grey GBp,
Melioderm Grey LLp,
Dermacron Grey N2B,
Dermacron Navy C 200%,
Dermacron Grey BL,
Colortech Grey LNG
Colortech Grey EGL
Leatherol Grey BL
192
SUMMARY
The main aim of the present work was to synthesize novel pyrazole derivatives and their dyes.
This was achieved by conducting multistep synthesis, including reactions like nitrosation,
reduction, diazotization, coulpling and metallization. Thus 1(p-sulfophenyl)-3-methyl-2-
pyrazoline-5-one was nitrosated and then reduced to an amine hydrochloride. The hydrochloride
was diazotized to produce a novel diazonium compound. The exact structure of the diazonium
compound was confirmed through its XRD and was found to be a diazoxide. This diazo
compound was coupled with various well known couplers to produce new dyes capable of
metallization. It is noteworthy to mention here that all the couplers selected were blocked at
position para so as to facilitate coupling of diazo at position ortho to the hydroxyl groups of
couplers.
In this work five series of dyes were prepared. These included:
i - Naphthol-AS series
ii - Pyrazolone series
iii - Naphthol series
iv - p-Substituted phenol and Resorcinol series
v - Bisphenol series
Each series is presented with a general structure in ―H‖ form as below:
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
O
O
NHM
R1 R2
R3
i-Naphthol-AS series
193
N
N
CH3
O
HO3SN N
N
N
R
O
R2
R1
R3
OH2OH2
OH2
M
ii- Pyrazolone series
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
M O R3
R1
R2
iii- Naphthol series
OH2OH2
OH2
HO3S
N
N
CH3
O
N N
M O
R1
R
iv- p-Substituted phenol series
OH2OH2
OH2
OH2OH2OH2
O
N
N
CH3
O
NN Ar-
N
N
CH3
O
N N
O
SO
Ar-
O
M
M
v- Bisphenol series (BPS-dye shown, where Ar- is p-sulfophenyl group)
194
The first series included naphthol-ASA, naphthol-ASBS, naphthol-ASD, naphthol-AS E,
naphthol-ASLC, naphthol-ASOL and naphthol-ASPH as couplers. In the 2nd
series pyrazolones
like 4-SPMP, SPCP, PMP, PTMP, 3-ClPMP, 3-SPMP and 2,5diClSPMP were used as couplers.
In the 3rd
series 5 different naphthols namely β-naphthol, Schaeffer’s Acid, R-Acid, H-Acid and
N-phenyl J-Acid were used as couplers. While the 4th
series included p-chlorophenol,
p-nitrophenol, phenol-4-suphonicAcid, 2-nitrophenol-4-suphonic Acid and resorcinol as
couplers. Similarly the couplers used in bisphenol series were bisphenol-S and bisphenol-A. The
general synthetic scheme was as under:
195
+ Na NO2 HCl+ + NaCl H2O+
+ Zn HCl+ + ZnCl2 H2O+
+ NaCl H2O+N
+
N
N
N
CH3
O-
O3S
N
N
CH3
ON
OH
HO3S
-Na
+
0 - 5 oC
(Nitrosation)
(Reduction)
(Diazotization)
144155
145146
146 147
HO3SN
N
CH3
OH
HO3SN
N
CH3
ON
OH
100 - 105 oCHO3S
N
N
CH3
OHNH3Cl
-
HO3S
N
N
CH3
OHNH3Cl
-+
+
NaNO2 + HCl
- 5 - 0 oC
N+
N
N
N
CH3
O-
O3S-
Na+
+
CH2
CH2OH N
N
N
N
CH3
OH
O3SCH2
CH2OHnaphtholic/phenolic coupler
(Coupling)
Na+ -
-Na
+
N
N
N
N
CH3
OH
O3SCH2
CH2OH
(Metallization) -Na
+
OH2
OH2
OH2
N
N
N
N
CH3
O
O3SCH2
CH2O
M
General Scheme; General synthetic scheme for the preparation of all dyes.
In the present work a total number of 104 dyes were synthesized and their fastness properties
were evaluated by application on cow crust. Most of the dyes had very good properties.Several
of these dyes had exactly the same shade as that of commercial dyes while other can be easily
formulated to get the desired shades as mentioned in National and International shade
comparisons. Although in this work 104 new dyes had been synthesized yet it is the opening of a
new era of scientific research and a lot work can be done in future.
196
FUTURE PROSPECTS
In the present work, as mentioned earlier, 2-pyrazoline-5-one have been used first time as a diazo
component containing an azo group at position 4 of pyrazoline ring. For this purpose the diazo of
SPMP has been synthesized and used as active component (amine component). Similarly other
pyrazolones like PMP, PTMP and SPCP may also be employed in the same manner. Several
other pyrazolones can also be exploited in the future.
The components used as couplers were various types of naphthols and phenols. Several other
naphthols, phenols and other couplers like acetoacetanilides and amines may also be used in the
future projects.
In this research work only chromium, iron and copper metal complexes has been prepared and
used as leather dyes. In future other metals can also be checked for their metallization (complex
formation).
While in the present work only acid dyes has been synthesized but in the future work other types
of dyes like azoic, reactive, disperse, substantive and even food dyes can also be synthesized and
evaluated.
In short there are tremendous opportunities to utilize these scaffolds for the custom build a vast
numer of dyes (metallized or not).
197
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