CORRELATION OF THE HYDRIDE AFFINITIES OF SUBSTITUTED AROMATIC CARBOCATIONS AND THE PROTON AFFINITIES OF SUBSTITUTED BENZENES CALCULATED BY MNDO WITH SIGMA+SUBSTITUENT CONSTANTS

MNDO-calculated heats of formation and ionization potentials of 248 structures involving substituted toluenes, diphenylmethanes (DPMH), xanthenes (XAN), 9H,10H-acridines (ACR), 9H-10-N-methylacridines (N-MACR), benzenes, and the corresponding carbocations are reported. Brown sigma-+ constants have been successfully correlated with the energies (DELTA-H(r)) of the isodesmic processes of bromination and protonation of substituted benzenes, solvolyses (dissociation) of substituted benzyl and benzhydryl (DPMCl) chlorides, hydride affinities of substituted aryl carbocations (benzyl, benzhydryl, etc.) as well as ionizations of substituted benzenes, toluenes, and diphenylmethanes. Comparisons of these results with experimental data and some ab initio theoretical calculations are also made.