D-Glucose adducts with zinc-group metal ions. Synthesis, and spectroscopic and structural characterization of Zn(II), Cd(II), and Hg(II) complexes with d-glucose, and the effects of metal-ion binding on the sugar anomeric structures

Abstract

The interaction of the zinc-group metal halide salts in solution with d-glucose has been investigated. Solid adducts of the type M( d-glucose)X 2· nH 2O, where M = Zn(II), Cd(II), or Hg(II); X = Cl − or Br −; and n = 4 or 2, were isolated and characterized by f.t.-i.r. and n.m.r. spectroscopy, and by molar conductivity measurements. The Zn(II)- and Cd(II)-glucose adducts appear structurally similar, binding to one d-glucose molecule, possibly through the 1-OH and 2-OH groups as well as to four H 2O molecules, forming a six-coordinate metal cation. The Hg(II) ion may be bonded to two sugar molecules (unidentately) and to two H 2O molecules, resulting in a four-coordinate structure around mercury. The binding of Zn(II) and Cd(II) is via the α anomer of d-glucose. The possibility cannot be excluded that the Hg(II) ion binds to both the α and β anomers.