ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 33, Number 2
JKCSEZ 33(2)
April 20, 1989 

Electrochemical reductions of trans-[Co(en)2X2](ClO4)n (where X is cyanide, nitrite, ammonia, and isothiocyanate) were investigated by cyclic voltammetry and polarography at mercury and glassy carbon electrode. trans-[Co(en)2(CN)2]ClO4 was reduced to Co(Ⅱ) complex followed by adsorption to the mercury electrode. Cyanide ion was not released from the reduced Co(Ⅱ) complex but the cyanide and (en) were released after the reduction to metallic cobalt. The other complexes except trans-[Co(en)2(CN)2]ClO4 were reduced to cobalt(Ⅱ) complexes followed by release of monodendate ligand, and (en) was released at the reduction step to metallic cobalt. trans-[Co(en)2(NO2)2]ClO4 was reduced to cobalt(Ⅱ) complex, and NO2- ion was released followed by electroreduction through ECE mechanism at pH 2. On glassy carbon electrode, all complexes of Co(Ⅲ) were reduced to Co(Ⅱ) complexes with irreversible one-electron diffusion controlled reaction in which (en) was not released at this step. Increasing absorption wave number of complexes caused to negative shift of peak potential.