Transition Metal Complexes of S-Propyl-L-Cysteine

Four transition metal complexes of the type M(L)(2) (M= Co, Ni, Cu, Zn and L=S-Propyl-L-cysteine) were synthesized and characterized by elemental analysis, spectral studies, thermo-gravimetric analysis, magnetic moment measurement and EPR. The complexes are proposed to have octahedral geometry around the metal atoms due to nitrogen and oxygen atoms. The ligand acts as a bridging ligand between two adjacent metal atoms leading to the formation of polymeric complexes. The carboxylate group in the ligand acts as bridging moiety between the two metal atoms. The polymeric nature of these complexes is also confirmed by the fact that they are insoluble in ordinary solvents. XAFS was used as confirmatory technique and it also shows octahedral environment around the central metal atom due to nitrogen and oxygen and clearly rejects the involvement of sulphur in the coordination sphere. EPR and XAFS show Jahn-Teller distortion around copper in the complex.