ELECTRONIC CHARGE-DENSITY DISTRIBUTIONS IN TETRATHIAFULVALENE DERIVATIVES

We have calculated electronic charge density distributions for typical representatives of tetrathiafulvalenes. We have applied a combined se mi-empirical and ab initio method to perform these calculations becaus e of the complexity of these molecules. Calculations have unambiguousl y shown an essential influence of modifications of the back-bone aroma tic group on the distribution of electronic charge density. Moreover, we have observed a substantial change of the charge density gradients under the influence of aromatic ring modifications. This leads to a st rong nonuniformity of the electronic charge density distribution. It i s surprising that the main charge density change is observed on the ot her molecule end than the structural modification (e.g. a substitution ) has been made. (C) 1998 Elsevier Science Ltd. All rights reserved.