First synthesis and characterization of zinc(II) complexes containing N-glycosides derived from ethylenediamine and D-glucosamine

Abstract

Zinc(II) complexes containing N-glycosides derived from D-glucosamine (D-GlcN) and ethylenediamine (en), [Zn(D-GlcN-en)₂]X₂ (1a X = Cl, 1b X₂ = SO₄^2–), were prepared and characterized by elemental analysis and nuclear magnetic resonance spectroscopy involving X-ray crystallography, where D-GlcN-en = 1-{(2-aminoethyl)amino}-2-amino-1,2-dideoxy-D-glucose. The complex cation of 1a has a nearly C₂ symmetry and the central zinc atom is octahedrally coordinated by two tridentate N-glycoside ligands from D-glucosamine and ethylenediamine. The N-glycoside ligand, D-GlcN-en, ligates to the zinc atom through the C² amino nitrogen atom of D-glucosamine and the two nitrogen atoms of the diamine in a meridional mode. The analysis of the solution conformation of the sugar ring in 1a based on vicinal coupling constants confirmed the similar structure revealed by X-ray crystallography.