Untersuchung von einfachen π-Elektronensystemen mit Hilfe von Elektronenspin-Resonanz und Polarographie

Abstract

It was the intention of this study to test the molecular orbital approximations of HÜCKEL and McLACHLAN by means of the experimental methods of EPR and polarography. In the experimental part problems are discussed as to electrolytic generation of free radicals and as to the ERP method with g-factors being measured with an accuracy of ± 2 ppm. In the theoretical part the molecular orbital theories of HÜCKEL and MCLACHLAN are summerized with particular regard to quantities which can be measured by EPR and polarography. A simple model of a σ → π → σ* excitation is developed which predicts a linear correlation between g-factor shift and π-energy of the lowest half-filled orbital. The validity of the model is discussed in terms of the g-factor theory recently deduced by STONE. The results of the experiments are presented in a subsequent paper.