POTENTIOMETRIC, POLAROGRAPHIC AND SPECTROSCOPIC STUDIES OF THE CU(II)-D-GLUCOSAMINE-D-LACTOBIONIC ACID TERNARY-SYSTEMS

Our recent work on Cu(II) and VO(IV) interactions with lactobionic aci d have shown1,2 that this sugar acid has an unusually high ability to coordinate both metal ions. The carboxyl group is not a very effective donor for cupric ions3,4 and metal interations with the set of the pr otonated hydroxyl groups should have considerable effects on complex s tability. This high stability of the lactobionic acid complexes can le ad to the involvement of this ligand in formation of ternary complexes with ligands such as aminosugars.3-6 Both ligands are important chela ting agents for Cu(II) ions in medicine, agriculture and food chemistr y.7-9 Since ternary complexes may play an important role in natural sy stems we have decided to follow complex formation in solutions contain ing lactobionic acid and one an aminosugar, D-glucosamine. The anchori ng group in D(+)-glucosamine (2-amino-2-deoxy-D-glucose) is an amino g roup which is much more effective donor than carboxylate which acts as an anchor in sugar acids. Thus in our study we have used excess lacto bionic acid to promote the formation of ternary complexes as major spe cies in the solutions studied.