ELECTROCHEMICAL AND ELECTRONIC SPECTROSCOPIC BEHAVIOR OF TRANS-BIS(ETHANEDIAL DIOXIMATO(1-),N,N') DIIODOCOBALTATE(III), [CO(GH)(2)I-2](-) IN CONNECTION WITH THE CATIONS H+, NH4+, ET(4)N(+), HQN(+) (QUINOLEINIUM)

The electrochemistry of six-coordinated cobalt(III) cobaloximatic salt s is reported in acetonitrile containing 0.1 M tetrabutylammonium hexa fluorophosphate as supporting electrolyte. The investigated compounds are represented as R[Co(GH)(2)I-2] where GH(-) is ethanedial dioximate or glyoximate and R = H+, NH4+, Et(4)N(+), Hqn(+) (quinoleinium). Eac h complex undergoes up to three oxidative processes and two metal-cent ered reduction steps within the potential range of the solvent. Except for Et(4)N[Co(GH)(2)I-2], all the other complexes display an addition al redox system situated between the two metal centered processes. The more likely origin for this additional redox signal is the reduction of the proton contained in the cations H+, NH4+ and Hqn(+) associated to [Co(GH)(2)I2](-) in the corresponding complexes. The electrochemica l behaviour of the cobaloximatic ion is only slightly influenced by th e counter cation. The electronic spectra of these compounds show three bands similar to those generally found for cobaloximes.