Alkyl Inductive Effects on Molecular Ionization Potentials. XVI. Esters

1973 ◽  
Vol 51 (23) ◽  
pp. 3963-3965 ◽  
Author(s):  
Leonard S. Levitt ◽  
Harry F. Widing ◽  
Barbara W. Levitt
Keyword(s):  
Lone Pair ◽  
Alkyl Substituent ◽  
Ionization Potentials ◽  
Electron Loss ◽  
Average Correlation ◽  
Inductive Effects ◽  
Substituent Constants ◽  
Average Standard Error ◽  
Straight Lines ◽  
Molecular Ionization

Correlation of molecular ionization potentials, E1, with Taft's alkyl inductive substituent constants, σ1(R), has now been extended to include the esters. It is found that three series of esters, the formates, acetates, and methyl alkanoates, fall on three separate straight lines in accord with the general equation E1 = E0 + a1σ1(R), where E0 is the intercept and a1 the slope. The average standard error for the three lines is 0.024 eV with an average correlation coefficient of 0.992, showing that the alkyl substituent exerts an inductive influence on the electron density at the site suffering the electron loss: a lone pair on either the carbonyl or alkoxy oxygen atom. Evidence is deduced for the site of electron expulsion and a prediction is made concerning the site of vapor phase protonation of esters and carboxylic acids. E1 values presently not available experimentally are predicted for several esters.

Inductive Effects on Molecular Ionization Potentials, XVIII Alkylpyridines and Alkylthiophenes. Molecular Orbital Calculations on Alkylbenzenes and Alkylpyridines

1977 ◽  
Vol 32 (10) ◽  
pp. 1160-1164 ◽  
Author(s):  
Cyril Párkányi ◽  
Leonard S. Levitt
Keyword(s):  
Molecular Orbital ◽  
Linear Correlation ◽  
Molecular Orbitals ◽  
Ionization Potentials ◽  
Molecular Orbital Calculations ◽  
Alkyl Groups ◽  
Inductive Effects ◽  
Substituent Constants ◽  
Linear Correlations ◽  
Molecular Ionization

Models of alkylbenzenes were treated by the HMO and SCF—MO methods and excellent linear correlations were found between the experimental ionization potentials, EI, and the energies of the highest occupied π-molecular orbitals calculated by the above-mentioned methods. A similar linear correlation was obtained for a group of methylpyridines. Also, the experimental ionization potentials of methylpyridines and alkylthiophenes have been linearly correlated with the sum of TAFT'S inductive substituent constants, ΣσI of the alkyl groups.

Alkyl Inductive Effects on Molecular Ionization Potentials. XIV. Amides

1975 ◽  
Vol 13 (1) ◽  
pp. 69-72 ◽  
Author(s):  
H. F. Widing ◽  
B. W. Levitt ◽  
L. S. Levitt
Keyword(s):  
Ionization Potentials ◽  
Inductive Effects ◽  
Molecular Ionization

Correlation between Alkyl Cation Affinities and Proton Affinities—A Means to Rationalise Alkyl Group Substituent Effects

2000 ◽  
Vol 6 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Einar Uggerud
Keyword(s):  
Linear Relationship ◽  
Alkyl Group ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Thermochemical Data ◽  
Proton Affinities ◽  
Alkyl Groups ◽  
Substituent Constants ◽  
Straight Lines ◽  
Methyl Cation

Using literature thermochemical data it is demonstrated that the known linear relationship between proton affinities and methyl cation affinities can be extended to other alkyl groups (ethyl, i-propyl, t-butyl). It is suggested that the slopes of the straight lines can be used to define a new set of alkyl substituent constants.

Inductive effects on molecular ionization potentials—VI

Tetrahedron ◽  
1972 ◽  
Vol 28 (13) ◽  
pp. 3369-3373 ◽  
Author(s):  
L.S. Levitt ◽  
B.W. Levitt ◽  
C. Párkányi
Keyword(s):  
Ionization Potentials ◽  
Inductive Effects ◽  
Molecular Ionization

Inductive effects on molecular ionization potentials—X

Tetrahedron ◽  
1973 ◽  
Vol 29 (7) ◽  
pp. 941-943 ◽  
Author(s):  
L.S. Levitt ◽  
B.W. Levitt
Keyword(s):  
Ionization Potentials ◽  
Inductive Effects ◽  
Molecular Ionization
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