Collect. Czech. Chem. Commun. 1998, 63, 187-198

Electrochemical Investigations of the Nickel(II)-Penicillamine System. Inert and Labile Complexes Detected by Polarography

Ana Iona, Florinel G. Banicab and Constantin Lucaa

a Universitatea Politehnica din Bucuresti, Catedra de Chimie Analitica si Analiza Instrumentala, Galea Grivitei 132, R-78122 Bucuresti, Romania
b Norwegian University of Science and Technology (NTNU), Department of Chemistry (Rosenborg), N-7034 Trondheim, Norway


The effect of penicillamine on nickel diffusion current demonstrates that Ni22- is a kinetically inert complex whereas NiL is labile (L2- = (CH3)2C(S-)CH(NH2)COO-)). The difference in kinetic stability between the analogous bis-ligand complexes of Ni(II) with either penicillamine or cysteine is tentatively explained taking into account their structures. It is suggested that nickel detoxication by chelate ligands depends on the inert character rather than on the thermodynamic stability of the relevant nickel complex.

Keywords: Amino acids; Chelates; Penicillamine; Nickel complexes; Nickel toxicology; Electrochemistry.