ElectrophilicitySupporting and Nucleophilicity Information ... · PDF fileESI-1 ElectrophilicitySupporting and Nucleophilicity Information (ESI-1) of Commonly Used Aldehydes Department
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ESI-1
Supporting Information (ESI-1)
Electrophilicity and Nucleophilicity of Commonly Used
Aldehydes
Sanjay Pratihar *
Department of Chemical Sciences, Tezpur University, Napaam,784028, Asam, India
Nucleophilicity (N) values of various mono, di, and tri-substituted aldehydes calculated at B3LYP/6-311+G** level of theory in gas phase.
8-9
Table S7. Experimental and theoretical Nucleophilicity(N), Electrophilicity (E),and Net E of various aldehyde from kinetics and theoretical (gas phase calculation in MI) analysis
10-11
Fig. S3. Theoretical nucleophilicity in acetonitrile versus Experimental nucleophilicity plot of various para substituted benzaldehydes in three different methods
12
Fig. S4. Theoretical electrophilicity in acetonitrile versus Experimental electrophilicity plot of various para substituted benzaldehydes in three different methods
12
Table S8. HOMO, LUMO, Hardness (,Chemical Potential ( elecytrophilicity (E),and Nucleophilicity (N) values of various mono, di, and tri-substituted aldehydes calculated at B3LYP/6-311+G** level of theory in acetonitrile in method I.
13-14
Fig. S5. Theoretical nucleophilicity in method I versus Experimental nucleophilicity plot of various aldehyde.
15
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Fig. S6. Theoretical electrophilicity in method I versus experimental electrophilicity plot of various para substituted benzaldehydes in three different methods
15
Table S9 Table S9. Electrophilicity of five different aldehyde in this method and by mayr et al.
16
Fig. S7. Experimental electrophilicity in method versus experimental electrophilicity by Mayr et al.
16
Table S10. Ln(K/T) versus (1/T) plot for the determination of activation parameter for KMnO4 oxidation reaction of five different para-substituted benzaldehyde.
17
Table S11. Ln(K/T) versus (1/T) plot for the determination of activation parameter for NaBH4 reduction of five different para-substituted benzaldehyde.
18
Table S12. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of six different para-substituted benzaldehyde at 298 K.
19
Table S13. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 291 K.
20
Table S14. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 283 K.
21
Table S15. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 275 K
22
Table S16. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 275 K.
23
Table S17. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 285 K.
24
Table S18. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 298 K.
25
Table S19. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 309 K.
26
Table S20. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 321 K.
27
Table S21. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 333 K.
28
Table S22. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of six different aldehyde at 298 K
29
Table S23. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different aldehyde at 298 K.
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Table S24. Ln(A) versus time plot for the determination of rate constant (k) for 31
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NaBH4 reduction of six different benzaldehyde at 298 K.
References 32
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Experimental Section:
Materials and Instruments: Double distilled water was used throughout the experiments.
Degassing of oxygen in water and acetonitrile has been done with bubbling of argon for 30
minute. Acetonitrile, aldehydes, and KMnO4 were of AR grade. All the reagents were used
without further purification. All UV-visible absorption spectra were recorded in a double beam
digital spectrophotometer attached with a chiller.
UV-vis study for KMnO4 Oxidation of aldehydes: At first an aqueous homogeneous solution
of KMnO4 (2 × 10-4 M) in double distilled oxygen free water has been prepared for the study. In
another set, 5 ml aldehyde stock solution (2 × 10-1 M) has been prepared in pre-distilled oxygen
free acetonitrile. Then 200 µL of aldehyde solution has been mixed with KMnO4 solution (4 × 10-
4 M) in a UV-cuvette to record the progress of the reaction. The progress of the reaction has been
accounted from a steady decrease of all the four absorbance maxima at specified band (506, 525,
545, and 566 nm) positions (Figure 1). All the rate measurement for KMnO4 oxidation of
aldehyde has been done with time scan option at fixed absorbance (545 nm band of KMnO4).
UV-vis study for NaBH4 reduction of aldehydes: For monitoring the reduction kinetics of
aldehydes, NaBH4 solution (20 M) in double distilled oxygen free water has been prepared. The
aqueous NaBH4 solution is admixed with 100 µL distilled oxygen free acetonitrile stock solution
(2 × 10-1 M) of corresponding aldehyde. All the rate measurement for NaBH4 reduction of
aldehyde has been done with time scan option at fixed absorbance band of a particular aldehyde.
Theoretical Background:
Global reactivity descriptors are defined for the system as a whole. Recently electrophilicity has
been defined by Parr et al.7a as the energy of stabilization of a chemical species when it attains an
additional fraction of electronic charge from the environment. The global electrophilicity index
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2
is defined as = /2 where is the electronic chemical potential1 and is the chemical
hardness.2
In an important contribution, Gazquez et al.9 have defined electrodonating power ( ) as
and (1))(2
2
AII
)(16
)3( 2
AIAI
Note that according to this definition, a low value of signifies a better electron donor. In the
present work nucleophilicity has been defined as the inverse of electrodonating power (10/ ) in
order to equate with the general notion that “more is better”. They also described
electroaccepting power ( ) as
and (2))(2
2
AIA
)(16
)3( 2
AIAI
Later on, Ayers et. al. introduced two sets of different equation from the IP and EA for both the
electrophilicity and nucleophilicity as8
and (3))(8)3( 2
AIAIN
)(8
)( 2
AIAIE
The electronic chemical potential and the chemical hardness have to be known for the calculation
of electrophilicity (E) and nucleophilicity (N) index. The electronic chemical potential is the
negative of electronegativity χ, is defined for an N-electron system with external potential v(r)
and total energy E as the partial derivative of the energy to the number of electrons at constant
external potential and in absence of a magnetic field:3
)(rVN
E
2AI
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where I and A are the vertical ionization energy and electron affinity, respectively. These two
quantities were calculated in Gaussian 03 program4 by using the B3LYP methods and 6-311+G**
as basis set. Hardness is defined as the corresponding second derivative as proposed by Parr and
Pearson.21
21
)(2
2
rvNE
)( AI
It is now common to exclude the factor ½ in the above definition. In this paper we calculated the
chemical hardness as the difference between the vertical ionization energy I and electron affinity
A. Where Ionization potential (IP) and A ELUMO = Electron affinity (EA)
The following absorbance band of aldehydes have been chosen for rate measurement of NaBH4
reduction of aldehyde (Table S1).
Table S1. Absorbane band ( max) of six different para substituted benzaldehydes.
Aldehyde max (nm)
4- (dimethyl amino) benzaldehyde 342
4-Methoxy Benzaldehyde 283
4-Methyl Benzaldehyde 263
Benzaldehyde 248
4-Bromo Benzaldehyde 263
4-Chloro Benzaldehyde 258
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Figure S1: Hammett plot of log(kY/kH) versus σp for KMnO4 oxidation of six different para substituted aldehyde.
Figure S2: Hammett plot of log(kY/kH) versus σp for NABH4 reduction of six different para substituted aldehyde.
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Table S2. Pseudo first order rate constant values of KMnO4 Oxidation of five different para substituted benzaldehydes.Temperature Cl (sec-1) Br (sec-1) H (sec-1) OMe (sec-1) NMe2 (sec-1)
Table S3. Pseudo first order rate constant values of NaBH4 reduction of five different para substituted benzaldehydes.Temperature Cl (sec-1) Br (sec-1) H (sec-1) OMe (sec-1) NMe2 (sec-1)
Theoretical Section: The ground state geometry optimizations of all the aldehydes were performed using GAUSSIAN 03.4 at B3LYP level of theory. All the atoms are treated with 6-311+G(d,p) basis set. Geometries of all species studied were fully optimized, and they were characterized as true intermediates on the potential energy surface by the absence of imaginary frequencies, after frequency calculation on the optimized geometries. During the reaction path analysis The transition state (TS) model of KMnO4 oxidation reaction has been analyzed at B3LYP level of theory. For Manganese Effective core potential (ECP) along with valence basis sets (LANL2DZ) was used, while for other atoms 6-311+G** basic set was used.
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Table S4. Optimized structure along with some important bond distance of aldehyde MnO4- intermediates.
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Table S5. Optimized Tranisition state (TS) structure along with some important bond distance of KMnO4 oxidation reaction.
Fig. S3. Theoretical nucleophilicity in acetonitrile versus Experimental nucleophilicity plot of various para substituted benzaldehydes in three different methods
Fig. S4. Theoretical electrophilicity in acetonitrile versus Experimental electrophilicity plot of various para substituted benzaldehydes in three different methods
Fig. S5. Theoretical nucleophilicity in method I versus Experimental nucleophilicity plot of various aldehyde.
Fig. S6. Theoretical electrophilicity in method I versus experimental electrophilicity plot of various para substituted benzaldehydes in three different methods
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Table S9. Electrophilicity of five different aldehyde in this method and by mayr et al.Aldehyde Electrophilicity (in this
Fig. S7. Experimental electrophilicity in method versus experimental electrophilicity by Mayr et al.
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Table S10. Ln(K/T) versus (1/T) plot for the determination of activation parameter for KMnO4 oxidation reaction of five different para-substituted benzaldehyde.
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Table S11. Ln(K/T) versus (1/T) plot for the determination of activation parameter for NaBH4 reduction of five different para-substituted benzaldehyde.
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Table S12. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of six different para-substituted benzaldehyde at 298 K.
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Table S13. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 291 K.
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Table S14. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 283 K.
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Table S15. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of Five different para-substituted benzaldehyde at 275 K.
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Table S16. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 275 K.
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Table S17. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 285 K.
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Table S18. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 298 K.
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Table S19. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 309 K.
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Table S20. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 321 K.
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Table S21. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different para-substituted benzaldehyde at 333 K.
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Table S22. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of six different aldehyde at 298 K.
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Table S23. Ln(A) versus time plot for the determination of rate constant (k) for KMnO4 oxidation of Five different aldehyde at 298 K.
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Table S24. Ln(A) versus time plot for the determination of rate constant (k) for NaBH4 reduction of six different benzaldehyde at 298 K.
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References
1 Parr, R. G.; Donnelly, R. A.; Levy, M.; Palke, W. E. J. Chem. Phys. 1978, 68,
3801.
2 Parr, R. G.; Pearson, R. G. J. Am. Chem. Soc. 1983, 105, 7512.
3 Parr, R. G.; Donnelly, R. A.; Levy, M.; Palke, W. E. Journal of Chemical Physics
1978, 68, 3801-3807.
4 Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.;
Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.;
Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.;
Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.;