What Quantum Chemistry Can Do for Forensic Science
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What Quantum Chemistry Can Do for Forensic Science Danielle Sapse and Nicholas D. K. Petraco John Jay College of Criminal Justice City University of New York mino Acid Alanine Reactivity with the Fingerprint Reagent Ninhydrin.
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Danielle Sapse and Nicholas D. K. Petraco John Jay College of Criminal Justice City University of New York. What Quantum Chemistry Can Do for Forensic Science. Amino Acid Alanine Reactivity with the Fingerprint Reagent Ninhydrin. H = E. Outline. - PowerPoint PPT Presentation
Transcript of What Quantum Chemistry Can Do for Forensic Science
What Quantum Chemistry Can Do for Forensic Science
Danielle Sapse and Nicholas D. K. PetracoJohn Jay College of Criminal Justice
City University of New York
Amino Acid Alanine Reactivity with the Fingerprint Reagent Ninhydrin.
Outline● How a Quantum Chemist can Help Forensic
Science● History and Trivia on Fingerprints● Ninhydrin + Alanine Gives Ruhemann’s
Purple● Results● Future Applications for Forensic Science
More fingerprints Explosives detection Probes for illegal drugs
Forensic Science – Quantum Chemistry A Potential Synergy
● Opportunity to improve communication between theorists and (bio) analytical chemists and biologists
● Computer speed always improving and big molecular systems can be treated
● Theory can't replace the lab but can help!
What Can We Learn From ?● Energy and Structures of Molecules
Molecular orbitals and relative energetics to help understand reactivity
Structures help us understand reactivity and design useful molecules such as materials, drugs and probes
● Electronic Spectra● Vibrational, Rotational Spectra● NMR and ESR Spectra● Thermodynamic data from Statistical-
Mechanics
A Forensic Science Classic: Fingerprints!
● Palm prints used for human identification in courts perhaps as early as 1st century Roman Empire
● 7th century China, was perhaps the first documented use of fingerprints as means of identification.
● It was probably Faulds (1880) who first proposed exploiting fingerprints for criminalistics in modern times.
● As a means of identification, fingerprints are still par excellence.1
Fingerprint Amplification● Latent prints, only trace amounts of biomaterial
– Very hard or impossible to see by themselves.
– Solution: Use some kind of developing agent.
Closed Shell Ground State
Singlet Exc. State
Triplet Exc. State
Ene
rgy Fluorescence
LaserPhosphorescence
I.S.C.
Fluorescence, Phosphorescence
● Fingerprint fluorescence is faint Treat fingerprint with materials to obtain
fluorescent or phosphorescent compounds
BeforeMenzel et al.
AfterMenzel et al.
Fingerprint Amplification
● Ninhydrin first suggested to develop latent fingerprints in 1950’s.
● Ninhydrin reacts with amino acids in fingerprints to produce Ruhemann's purple
o Brightly colored and easy to identify by eye
o Fluoresces slightly at the 582 nm and 407 nm when treated with a zinc or cadmium salts
o Starting material, ninhydrin, is cheap
Ninhydrin-Ruhemann’s Purple System
O
O
OH
OH
O
OH O
O
N
ninhydrin Ruhemann’s purple
● Synthesize new compounds with properties superior to Ruhemann's purple.
● No known chemical system which offers significant advantages in color to Ruhemann’s purple.
Ultimately we want to help improve chromogenic and fluorogenic properties
● An unequivocal understanding of the mechanism of formation for Ruhemann’s purple is important!
The mechanism for the reaction between amino-acids and ninhydrin was never fully settled.
McCaldin Mechanism Lamothe Mechanism Friedman Mechanism
● We have attempted to understand these mechanisms using ab-inito computations.
Motivation
● Structures of all molecules in McCaldin, Lamothe and Friedman mechanisms optimized at RHF-SCF level using a 6-31G* basis set and analytic derivative methods. Gradients optimized to > 0.0001 a.u.
Largest Abelian point groups used
● Harmonic vibrational frequencies computed for all structures using finite difference of analytic gradients. All computed structures found to be energetic minima
● Benchmark structures for ninhydrin, alanine and Ruhemann’s Purple were found using DFT B3LYP and a 6-31G**.
Computational Methods
Structure (Abelian point group) DFT 6-31G** B3LYP Energy (hartree)
Ninhydrin (C2) -647.460616
Alanine (C1) -323.747976
Ruhemann’s Purple isomer 1 (C1) -1046.957475
1.086
1.085
1.394
1.406
1.395
1.483
1.214 1.549
1.399
0.971
121.0
118.0
121.0
110.4
107.6
103.9
113.5
106.1
1.085
1.086
1.393
1.395
1.405
1.491
1.216 1.512
1.513
1.489
1.286
1.368
1.218
1.376
1.503
1.337
0.967
1.214
1.475
1.506
1.406
1.387
1.3791.408
1.393
1.407
1.395
1.404
1.086
1.085
1.405
1.088
1.086
1.085
1.085
121.1
118.0121.0
121.0
118.0110.0
110.3
105.8107.5
105.8121.1
122.0 122.543.3
111.0
107.7
108.1105.6
107.5118.1
121.1
120.6118.1
121.5
120.7
DFT Benchmark Structures
ninhydrin
Ruhemann’s Purple
General Scheme for the Reaction of Ninhydrin with -amino acids to form Ruhemann’s Purple
CO2
aldehyde
ninhydrin + -amino acid Strecker degradation Strecker degradation intermediate
dehydrationand hydrolysis
several intermediates
hydrindantin and possible side products
Ruhemann’s Purple
McCaldin
Mechanism
DE kcal/mol
a ninhydrin + alanine 1 + H2O
7.08
b 1 2 + H2O + CO2 2.22
c 2 + 2 H+ 4 -4.35
d 2 + H2O 3 + acetald -9.55
e 4 + H2O 3 + acetald -5.20
f 3 + H2O 6 + NH3 3.50
g 3 + H2O 7 + NH3 -8.76
h 6 7 -12.26
i 3 + nin 5 + H2O -8.42
j 7 + nin + 2 H+ 8 + H2O
1.36
k 5 RP + H2O + H+ 28.94
O
O
OH
OH
ninhydrin
+ H2N CHC
CH3
OH
O
alanine
- H2O
a
O
O
OH
NH
CHC
CH3
OH
O
- H2O- CO2
b1
O
O
HN CH CH3
2
+ 2H+c
O
OH
N CH CH3
4
O
OH
NH2
3
HCOCH3 +
+ H2Od
O
O
OH
7
+ H2O
e
+ H2Og
O
OH
OH
6
- NH3
f
h
j+ ninhydrin+ 2H+
- H2O
O
O
OH
O
O
HO
i+ ninhydrin
- H2O
O
O O
O
HONH
k- H+
- H2OO
OH O
O
N
5
Ruhemann's Purpleisomer 1
8
O
O O
O
NH
Ruhemann's Purpleisomer 2
O
O O
ONH
Ruhemann's Purpleisomer 3
Lamothe
Mechanism
DE kcal/mol
l 3 + ninhydrin 6 + 9 + H2O
22.68
m 6 + ninhydrin 8 + H2O
-10.90
n 3 + ninhydrin 5’ + H2O
8.62
o 6 + 9 RP + H2O -2.16
p 5’ RP + H2O 11.90
O
O
OH
OH
ninhydrin
+ H2N CHC
CH3
OH
O
alanine
- H2O
a
O
O
OH
NH
CHC
CH3
OH
O
- H2O- CO2
b1
O
O
HN CH CH3
2
+ 2H+c
O
OH
N CH CH3
4
O
OH
NH2
3
HCOCH3 ++ H2O
e
O
O
NH
9
- H2O
O
OH
OH
6
l
m + ninhydrin- H2O
O
O
OH
O
O
HO
n+ ninhydrin
- H2O
OH
O O
O
HONH
p - H2O
O
OH O
O
N
5'
+ ninhydrin
+
8
o - H2O
Ruhemann's Purpleisomer 1
O
O O
O
NH
Ruhemann's Purpleisomer 2
O
O O
ONH
Ruhemann's Purpleisomer 3
Friedman
Mechanism
DE kcal/mol
r ninhydrin 10 + H2O 17.95
s 10 + alanine 1 -10.87
t 1 11 + H2O 9.21
u 11 4 + CO2 -11.34
v 4 12 -8.19
w 12 + H2O 3 + acetald 2.99
q 3 + ninhydrin RP + 2 H2O + 2 H+
20.52
O
O
OH
OH
ninhydrin
+ H2N CHC
CH3
OH
O
alanine
- H2O
r
O
O
OH
NH
CHC
CH3
OH
O
- H2Ot
1
O
O
N CH CH3
11
- CO2u
O
OH
N CH CH3
4
O
OH
NH2
3
HCOCH3 +
O
O
OH
7
+ H2O
w
+ H2Og
- NH3
j+ ninhydrin+ 2H+
- H2O
O
O
OH
O
O
HO
q
+ ninhydrin- 2H2O
- 2H+
O
OH O
O
N
8
O
O
O
10
s
COOH
v
O
O
N CH CH3
12
Ruhemann's Purpleisomer 1
O
O O
O
NH
Ruhemann's Purpleisomer 2
O
O O
ONH
Ruhemann's Purpleisomer 3
O
O
OH
OH
ninhydrin
+ H2N CHC
CH3
OH
O
alanine
- H2O
a
O
O
OH
NH
CHC
CH3
OH
O
- H2O- CO2
b1
O
O
HN CH CH3
2
+ 2H+c
O
OH
N CH CH3
4
O
OH
NH2
3
HCOCH3 +
+ H2Od
O
O
OH
7
+ H2O
e
+ H2Og
O
OH
OH
6
- NH3
f
h
j+ ninhydrin+ 2H+
- H2OO
O
OH
O
O
HO
i+ ninhydrin
- H2O
O
O O
O
HONH
5
OH
O O
O
HONH
p - H2O
O
OH O
O
N
5'
n+ ninhydrin
- H2O
Ruhemann's Purpleisomer 1
O
O O
O
NH
Ruhemann's Purpleisomer 2
O
O O
ONH
Ruhemann's Purpleisomer 3
Our postulated mechanism at 25oC
New HF-6-31G** Results on Substituted Ninhydrin-Ruhemann’s Purple Systems
Ruhemann’s Purple Substitution
DE
kcal/mol
unsubs RP 17.52
RP-F (11) 17.12
RP-F (12) 17.55
RP-NH2 (13) 27.72
RP-NH2 (14) 19.66
RP-OCH3 (15) 22.34
RP-OCH3 (16) 28.27
RP-OH (17) 26.91
RP-OH (18) 19.94
Intermediate Structures
DE
kcal/mol
unsubs (19) 3.14
int.-F (20) -1.45
int.-F (21) 6.51
int.-NH2 (22) 6.50
int.-NH2 (23) 3.51
int.-OCH3 (24) 6.94
int.-OCH3 (25) 6.19
int.-OH (26) 8.24
int.-OH (27) 1.87
O
O
OH
OH+ H2N CHC
CH3
OH
O
2
R
H2O CO2HCOCH3
O
OH O
O
N + + +3
R
R
R= HFNH2OCH3OH
O
O
OH
OH+ H2N CHC
CH3
OH
O
R
O
O
OH
NH
CHC
CH3
OH
O
R
● Future Projects
Compute low lying excited electronic and vibrational states to predict fluorescent/ phosphorescent ability
Tailor molecules to cheap portable lasers!• Ruhemann's Purple-Transition Metal-Halide• Explore substituted ninhydrines• Derivatives of indanediones• Quantum Dots!
• Clusters of Atoms• Exotic quantum properties• Phosphoresce well
Forensic Science – Quantum Chemistry
Forensic Science – Quantum Chemistry ● Explosives Detection
Live in an age of terrorism Many articles to examine Ideally testing must be
Fast and user friendly Portable Safe and reliable
Lanthanide complexes Have been useful for finger prints Phosphoresce well Coordinate well with explosives Quantum Dots
Forensic Science – Quantum Chemistry ● Quantum Chemistry can help with design
Metal and Ligand excited states Determine efficiency of metal-ligand energy
transfer process Indicate ligand structures to prevent binding of
unwanted species● Metal-Ligand possibilities
Europium, Terbium Derivatives of thenoyiltrifloroacetone and
othrophanthrolene● Quantum dots CdS, CdSe, GaAs, InAs
Forensic Science – Quantum Chemistry
S
O
CF3
O
NN
thenoyiltrifloroacetone othrophanthrolene
Forensic Science – Quantum Chemistry ● Molecular Sensors
Miniaturization to the molecular level Improve selectivity and detection limits Widen range of detectable analytes Sensor modeling allows optimization of
response properties to analyte Important factors
• Molecular topology• Binding site geometry• Binding and stabilizing interactions
Few probes for illegal drugs, yet many binding sites
Forensic Science – Quantum Chemistry ● Molecular Sensors for canabinols and
amphetamines Species are of reasonable size
C5H
11O
OH
R
Canabinol 3,4-Methylenedioxymethamph.
O
ONH
Forensic Science – Quantum Chemistry ● Ferrocene based barbiturate sensors
R
R
HN
O
O
HN
R R
HN HN
N N
N
NO
O
Fe
Fe
● John Jay College of Criminal Justice
● Our co-authors:
o Prof. Anne-Marie Sapse
o Prof. Gloria Proni
o Jennifer Jackiw
● Our collaborators and colleagues:
o Prof. Thomas Kubic
o Chris Chen
o Chris Barden
o Prof. Jon Riensrta-Kiracofe
o Detective Nicholas Petraco (NYPD ret.)
o Officer Patrick McLaughlin (NYPD)
Acknowledgments
