Electrochemical behaviour of cobalt(II) L-amino acids in aqueous dimethyl formamide, N-methylformamide and formamide media at dropping mercury electrode

Polarographic technique has been used to evaluate the kinetic parameters and formation constants of cobalt(II) complexes with L-arginine, L-lysine, L-tryptophan, L-tyrosine, L-aspartic acid and L-glutamic acid at pH 8.40 +/- 0.20 and at a constant ionic strength (mu = 0.1) in aqueous dimethylformamide (DMF), N-methylformamide (NMF) and formamide mixture (v/v) at d.m.e. The reduction of all these complexes is found to be irreversible. The kinetic parameters (K-fh(0), alpha n, xi) for these complexes were calculated using Meites-Israel method and its modification by Gaur and Bhargava. In all these cases a single reduction wave is obtained and i(d) value decreases with increase in the percentage of solvent (20-60% v/v). Further it was observed that E-1/2 value shifted towards more negative side in all Co-II complexes in NMF medium possibly due to high. dielectric constant and viscosity of the medium.