MONOSUBSTITUTED BENZENES - SOME FEATURES OF THE ELECTRON-DENSITY DISTRIBUTION OBTAINED BY ABINITIO CALCULATIONS

A comparative analysis was made of the electron density distribution in monosubstituted benzenes by the nonempirical LCAO-MO SCF STO-3G method It was shown that the effective charge that appears at the carbon atoms of the benzene ring as a result of introduction of the substituent is divided into pi and sigma components in the same proportions, irrespective of the position of the carbon atoms (ortho, meta, para). It was established that there are also linear relationships between the pi charges of the ortho, meta, and para carbon atoms of monosubstituted benzenes. Thus, the changes in all the pi and sigma charges of the ortho, meta,and para carbon atoms during substitution in benzene are related linearly to each other. The obtained equations in the generalized form reflect the response of the benzene ring to substitution.