Substantially Conductive Polymers

Part 04

Witting Condensation

Ph3P CH CH PPh3 + C CO

HO

HCH CH

n

R. N. McDonald et. al. JACS 82,4669 ( 1960 )G. E. Wnek et. al. Polymer 20,1441 ( 1979 )

Ph3P CH CH PPh3 Ph3P CH C

PPh3

HC C

O

HO

H

Ph3P CH C

PPh3

HC C

O

H

H

OH

Ph3P CH C

Ph3P

HC C

O

H

H

O

Ph3P CH CH

C CO

H

Hetc. CH C

HCH C

HCH C

Hetc.

Ph3P BrH2C CH2Br

triphenyl phosphine

Ph3P H2C CH2 PPh3

Br Br

Base (like LiBu)

Ph3P HC CH PPh3Ph3P CH CH PPh3Phosphorus ylide (phosphorus-stabilized carbanion) 2

Dehalogenation

Cl

Cl3C CCl3

ClCl

Cl- Cl2

Cl

CCl

ClCl

Cl

CCln

M. Ballester et. al. JACS 88, 957 ( 1966 )

McMurry Condensation (TiCl3/LiAlH4)

OHC CHO- "O2"

CH CHn

L. Rajaraman et. al. Curr. Sci. 49 (3), 101 ( 1980 )

CO

CO - "O2"

C Cn

Feast et. al. Polymer Commum. 24,102 ( 1983 )

3

ClH2C

R

R

CH2ClNaH/DMF

-HClCH CH

n

R

R

( R = H, CH3, OCH3)

H. H. Horhold et. al. Makromol. Chem. 131, 165 ( 1970 )

C C

H

H

C CH

H

H

Cl

H

Cl

H

H

Cl

etc. CH2HC CH2

Cl

HC

Cl

CH2HCCl

CH CHn

C C

PhPh

N2 N2- N2 C C

Ph Ph

n

Dehydrohalogenation of Benzyl Halides

From Bis(diazobenzylic) Compounds

4

C C

PhPh

carbene intermediate

-HCl

ClH2C CH2Cl + SMe2 H2C CH2Me2S SMe2

ClClbissulfonium salt

NaOH

CH CHn

CH2HC

nSMe2

Cl

£G

Casting

sulfonium polyelectrolyte

£G

Casting dialysis

-NaCl- low MW molecules

+ NaCl

R. A. Wessling et.al.J. Polym. Sci. Polym. Symp.,72, 55( 1986 )U. S. Patent 3,706, 677 ( 1972 )U. S. Patent 3,401, 152 ( 1968 )

Via Sulfonium Polyeletrolyte Precursor

5

- SMe2

- HCl

C CMe2S SMe2

ClCl

H

H

H

H

NaOH

C CMe2S SMe2

H

H

H

C CSMe2

H

H

H

Cl

quinone dimethane

C CSMe2

H

H

H

Cl

diradical

Initiates the polymerization of quinone dimethane

6

C CSMe2

H

H

H

Cl

Other possible mechanism :

Nu C CSMe2

H

H

H

Nu

C CSMe2

H

H

H

Cl

CH2HC

nSMe2Cl

H2C CH2 SMe2

ClClCH2

HC

nSMe2

NaOH dialysis

(25 - 35 % yield)Acid titration : > 90 - 95 % NaOH has been consumed.

Why ?

Cl

Me2S

May be :

CH2 S

ClCl

NaOHMe

Me

a

ba

b

H2C CH S

Me

Me

H2C CH2 S

Cl

Me

MeOH+

non-productive pathwaysulfonium polyelectrolyte

H2CMe2S

Me2SMe2S

Cl