COMPLEXES OF COBALT(III) WITH D-GLUCOSAMINE AND AMINES

Abstract

D-Glucosamine and ammonia, 1,2-ethylenediamine, or 1,10-phenanthroline form complexes with Co(III)*. The complexes are: [Co(NH3)3-H2O-D-glucosamine]3+, [Co(en)2.D-glucosamine]2+ and [Co(phen)2.D-glucosamine]3+. Formation of the last two complexes is stereospecific with Co(III), with predominance of the DELTA over the LAMBDA diastereomer. The DELTA and LAMBDA diastereomers of the ethylenediamine and phenanthroline complexes with D-gluCOsamine were separated and their configurations about Co(III) assigned from the CD and ORD spectra. The ethylenediamine complex has pK(a) approximately 3.4 and is more acidic than the other complexes, pointing to coordination of the alkoxide residue at position 1 of glucosamine.