Coordination ability of selected amino sugars with Cu2+ ions in solution

Complex formation between Cu(II) and the amino sugars methyl-beta-L-daunosaminide (MeDauN), 6-amino-6-deoxy-D-glucose (Glc6N), 3-dimethylamino-3,4,6-trideoxy-D-xyloheksose (desosamine DSA), and methyl-3-amino-3-deoxy-alpha-D-mannopyranose (MeMan3N) was studied in aqueous solution by potentiometric and spectroscopic (EPR, electron absorption, and CD) techniques. The results show that Glc6N and DSA ligands, lacking the cis-oriented couples of [NH2, OH] donors, give rise only to dimeric complexes. The other two ligands, although both forming mononuclear species, exhibit different coordination abilities, depending on the assistance of donors able to yield axial interaction with the metal ion.