Glucosamine Research Today is a free monthly online journal that collates and summarizes the latest research about Glucosamine, including details on chondroitin sulfate, uses, effects, benefits, arthritis. | ||||||||
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Nickel(II) complexes with Schiff-base ligands derived from epimeric pyranose backbones as 2,3-chelators: modeling the coordination chemistry of chitosan.Burkhardt A, Görls H, Plass W Lehrstuhl für Anorganische Chemie II, Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Carl-Zeiss-Promenade 10, D-07745 Jena, Germany. Two mononuclear nickel(II) complexes with Schiff-base ligands derived from the epimeric sugars glucosamine and mannosamine have been synthesized. The X-ray crystal structure reveals a distorted octahedral geometry at the nickel(II) ions with an N4O2 donor set and the rare 2,3-chelation of the donor atoms of the carbohydrate backbone. Upon complexation only the glucopyranose ring maintains the 4C1 chair conformation, whereas the mannopyranose ring adopts the OS5 screw-boat conformation. Dimeric units of complex cations are formed by intermolecular hydrogen bonding which are further assembled by pi-stacking affording one-dimensional chains with a twofold screw symmetry. Published 18 April 2008 in Carbohydr Res, 343(7): 1266-77.
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