Equilibrium and spectroscopic studies of transition metal complexes of sugar-containing thiazolidine derivatives
Abstract
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 MpLqHr 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.