EQUILIBRIUM AND SPECTROSCOPIC STUDIES OF TRANSITION-METAL COMPLEXES OF SUGAR-CONTAINING THIAZOLIDINE DERIVATIVES

Transition-metal co-ordination equilibria of 2(RS)-D-galactothiazolidine-4(R)-carboxylic acid were studied by potentiometric titrations in the range pH 1.5-8.5. In most cases, (1,1,1), (1,2,0) and (1,2,0) parent complexes M(p)L(q)H(r) were formed, but in the cases of oxovanadium(IV), manganese(II) and zinc(II) at > pH 6 mixed-ligand complexes involving hydroxide-ion co-ordination or further deprotonation of alcoholic hydroxy groups were also observed. EPR measurements indicated that the manganese(II) complex is dimeric, while that of VO2+ is monomeric.