COMPLEXES OF ALPHA-DIIMINES WITH PENTAMET HYLCYCLOPENTADIENYLRHODIUM IN DIFFERENT OXIDATION-STATES

Cationic complexes [CpRhCl(alpha-diimine)]+ of trivalent rhodium and heterocyclic alpha-diimines or 1,4-disubstituted 1,4-diazabutadienes w ere isolated as hexafluorophosphates und subjected to electrochemical studies. Chemical or electrochemical two electron reduction yields int ensely coloured and highly reactive neutral complexes CpRh(alpha-diim ine) which are very easily oxidized and which can be reduced further a t negative potentials. The electronic structure of these compounds was studied using H-1-NMR and UV/Vis spectroscopy. Comparisons of charge transfer (CT) transition energies with redox potentials suggest very v ariable geometrical changes between ground and CT excited states.