AN ELECTROCHEMICAL STUDY OF SOLVENT-COMPLEX INTERACTIONS IN INOCYCLOHEXANE-N,N,N',N'-TETRAACETATOCHROMATE(III) AND ANE-N-HYDROXYETHYL-N,N',N'-TRIACETATOCHROMIUM(III)

The electroreduction of inocyclohexane-N,N,N',N'-tetraacetatochromate( III) and ane-N-hydroxyethyl-N,N',N'-triacetatochromium(III) has been i nvestigated in different solvents on a mercury electrode by convolutio n potential sweep voltammetry. The dependence of the observed diffusio n coefficients, standard potentials and double layer corrected electro n transfer rates on solvent properties has been interpreted. It has be en shown that the formal potentials for the reduction of both complexe s are linear functions of the solvent acceptor numbers. The logarithm of the corrected standard rate constant for the rans-1,2-diaminocycloh exane-N,N,N',N'-tetraacetato complex depends on both the acceptor numb er and the logarithm of the solvent's longitudinal relaxation time. On the other hand in case of the ,2-diaminoethane-N-hydroxyethyl-N,N',N' -triacetato complex, this quantity depends on the solvent's acceptor a nd donor number. It is concluded that the ane-N-hydroxyethyl-N,N',N'-t riacetatochromium(III) complex undergoes substitution of the coordinat ed water molecule originally present as a ligand. However, for the ran s-1,2-diaminocyclohexane-N,N,N',N'-tetraacetato chromium(III) complex there is no indication of the incorporation of solvent molecules in th e first coordination sphere as a ligand. Copyright (C) 1996 Elsevier S cience Ltd.