The tridentate metal-binding sites of the common glycoses.
Co(III)(tacn) and Ga(III)(tacn) fragments (tacn = 1,4,7-triazacyclononane) are suitable metal probes for the detection of the tridentate chelating sites of a glycose. Three moles of hydroxide per mole of cobalt or gallium support triple deprotonation of the chelating triol functions at a glycose's backbone. The individual chelating sites are detected using 1D and 2D NMR techniques. The metal-binding sites always include the hydroxy function at the anomeric carbon atom. Chelators are derived from both the pyranose and the furanose isomers while forming five- and six-membered chelate rings by the use of cis,cis-1,2,3-triol functions. The assignment of less frequently occurring ligand isomers are supported by a DFT approach. Crystal-structure analysis on Na(4)[Cr(beta-d-Manf1,2,3H(-3))(2)]NO(3).8.5H(2)O (Man = mannose) additionally upholds the NMR assignments.
Ghaschghaie
Natascha
N
Department of Chemistry and Biochemistry of the Ludwig Maximilian University Munich, Butenandtstr. 5-13, D-81377, Munich, Germany.
Hoffmann
Thomas
T
Steinborn
Martin
M
Klüfers
Peter
P
D001665:Binding Sites; D002384:Catalysis; D002614:Chelating Agents / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005708:Gallium / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012266:Ribose / Q000737:chemistry
D002614:Chelating Agents; D006571:Heterocyclic Compounds; D003035:Cobalt; C075712:1,4,7-triazacyclononane; D012266:Ribose; D005708:Gallium