THE FIRST IONIZATION-POTENTIALS AND CONJUGATION IN BENZENE-DERIVATIVES CONTAINING ORGANOSILICON, ORGANOGERMANIUM, ORGANOTIN, AND ORGANOLEADSUBSTITUENTS

The inductive and resonance effects of silicon-, germanium-, tin-. and lead-containing and some organic substituents on the HOMO energies (E -HOMO) for 43 monosubstituted and p-disubstituted benzene derivatives were analysed in the Koopmans approximation. A linear dependence betwe en the perturbation energy delta E and the resonance sigma(R)(+) param eters of the substituents was established. The Koopmans approximation is a rough approximation for the compounds studied, since to provide f or its rigorous fulfilment. the delta E values must depend on the sigm a(R)(0) parameters of the substituents. The principal regularities of increasing the sigma,pi-conjugation between the organoelement substitu ents and the pi-system caused by a positive charge on the benzene ring were established.