Dipole moments, charge-transfer parameters, and ionization potentials of the methyl-substituted benzene–tetracyanoethylene complexes

Abstract

The dipole moments of a series of charge-transfer complexes of methylbenzenes with tetracyano-ethylene in carbon tetrachloride solutions at 25 °C and the various parameters derived from Mulliken's theory have been evaluated. The energies of various states of the complexes were calculated via their relationships with the parameters, charge-transfer transition energies, and heats of formation of the complexes by means of the variation principle. Vertical ionization potentials of the donors were obtained from the calculated energies of the dative structures of the complexes. The dipole moments contributed from the charge-transfer interaction can also be reasonably interpreted as charge-transfer energies in terms of vertical ionization potentials of the donors.