Correlation of Ionization Potentials and the Sums of Substituent Constants for Substituted Benzenes

1973 ◽  
Vol 51 (18) ◽  
pp. 3065-3070 ◽  
Author(s):  
Harry W. Gibson
Keyword(s):  
Ionization Potentials ◽  
Mo Calculations ◽  
Substituted Benzenes ◽  
Substituent Constants ◽  
Occupied Orbital ◽  
Better Than ◽  
Electrostatic Theory

Previously reported experimentally determined ionization potentials of substituted benzenes are well correlated by the sum of the para substituent constants, regardless of the orientation of the substituents. σ+ is better than σ for this purpose. Tri-through hexasubstituted benzenes are also correlated, but the slope and intercept are higher in accord with electrostatic theory. These results in support of recent MO calculations indicate that substituent constants are good measures of the energy of the highest occupied orbital.

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.

IONIZATION POTENTIALS OF METHYL-SUBSTITUTED BENZENES AND CYCLOPENTADIENES

1964 ◽  
Vol 42 (10) ◽  
pp. 2256-2261 ◽  
Author(s):  
F. Meyer ◽  
A. G. Harrison
Keyword(s):  
Electron Impact ◽  
Experimental Results ◽  
Ionization Potentials ◽  
Orbital Method ◽  
Substituted Benzenes ◽  
Group Orbital

The ionization potentials of a number of methyl-substituted benzenes and cyclopentadienes have been measured by electron impact. The experimental results are compared to calculations based on a group orbital method.

Linear free energy relationships. VIII. Ionization potentials of aliphatic compounds

1977 ◽  
Vol 55 (14) ◽  
pp. 2637-2641 ◽  
Author(s):  
Harry W. Gibson
Keyword(s):  
Free Energy ◽  
Solution Phase ◽  
Ionization Potentials ◽  
Linear Free Energy Relationships ◽  
Aliphatic Compounds ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Ring Nitrogen ◽  
Substituent Constants ◽  
A Site

Ionization potentials (IP) of HX, CH3X, C2H5X, and i-C3H7X, where X is a substituent with non-bonded electrons, are directly proportional to ionization potentials of 4-substituted quinuclidines. This is taken as evidence that in general the energy required to remove an electron from a substituent X, as is the case in HX, CH3X, C2H5X, and i-C3H7X, is directly proportional to the energy required to remove an electron from a site remote from the substituent, as in the quinuclidines in which an electron is lost from the ring nitrogen. Furthermore, the IP's of the HX-i-C3H7X series are directly proportional to inductive substituent constants, σI, providing a valuable correlation between gas and solution phase behavior.

An evaluation of empirical methods for calculating the ionization potentials of substituted benzenes

1976 ◽  
Vol 11 (2) ◽  
pp. 207-211 ◽  
Author(s):  
John M. Behan ◽  
Robert A. W. Johnstone ◽  
T. William Bentley
Keyword(s):  
Ionization Potentials ◽  
Empirical Methods ◽  
Substituted Benzenes

Structural Effects on Nitrile Infrared Integrated Intensities of Alpha,Beta-Diaryl Cyanoethylenes: Hammett and Quantum Chemical Approaches

1978 ◽  
Vol 33 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Ivan Juchnovski ◽  
Rositza Kuzmanova ◽  
Jordan Tsenov ◽  
José Kaneti ◽  
Ivan Binev
Keyword(s):  
Steric Hindrance ◽  
Quantum Chemical ◽  
Nitrile Group ◽  
Structural Effects ◽  
Mo Calculations ◽  
Infrared Intensities ◽  
Substituent Constants ◽  
Alpha Beta ◽  
Integrated Intensities ◽  
Derivatives Of

AbstractThe nitrile infrared intensities of a series of a,β-diaryl cyanoethylenes were juxtaposed to the associated substituent constants, HMO and SCF-MO indices and fair to excellent correlations were established. The competitive resonance of the nitrile group with alpha-and beta-aryl substituents is discussed. HMO calculations were used to estimate the steric hindrance to conjugation caused by polycyclic substituents and SCF-MO calculations were made to obtain uniform predictions of nitrile intensities and frequencies for hetero-cyclic derivatives of acrylonitrile.

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