A SPECTROSCOPIC STUDY OF THE INTERACTION OF THE VO2+ CATION WITH THE 2 COMPONENTS OF CHONDROITIN SULFATE

The interaction of the vanadyl (IV) cation with N-acetyl-D-galactosami ne, D-galactosamine, and D-glucuronic acid has been investigated by el ectron absorption spectroscopy at different metal to ligand ratios and pH values. In the case of D-glucuronic acid, a more detailed study wa s undertaken, using differential IR spectroscopy in solution. The resu lts show that the cation interacts with the two nitrogenated molecules only at higher pH values, generating 2:1 ligand to metal complexes in which coordination occurs through two pairs of deprotonated OH groups of the rings. In the case of D-glucuronic acid, the IR-measurements a llowed a wider insight into the structural characteristics of the comp lexes generated in acidic media. The involvement of the glycosidic oxy gen atom in coordination, is suggested at pH = 3.