SYNTHETIC MODELS FOR THE GLUCOSE-TOLERANCE FACTOR - THE SPECTROSCOPICCHARACTERIZATION AND TOXICITY STUDIES OF MONOMERIC AND DIMERIC CR(III) SPECIES

A number of chromium(III) complexes with glycine, cysteine, glutamic a nd nicotinic acids-models for biologically active Cr(III) species-have been prepared and characterized with physicochemical methods (UV/Vis, IR spectra, magnetic moments). Four of them have been also tested for their toxicity. On the basis of CF calculation it was found that only the nicotinates were octahedral Cr(III) species. Other complexes exhi bited a tetragonal deformations. Based upon 10 Dq values, the sequence of the ligand field strength was found to be: glycine> cysteine appro ximate to glutamic acid>nicotinic acid. The likely structures were pro posed for the isolated compounds. The preliminary toxicity studies sho wed that all tested complexes appeared to be nontoxic and can be poten tially applied as chromium nutrition products. (C) 1998 Elsevier Scien ce Ltd; All rights reserved.