Transition-metal saccharide chemistry: synthesis and characterization of d-glucose, d-fructose, d-galactose, d-xylose, d-ribose, and maltose complexes of Co(II)

Monosaccharide (d-Glc, d-Fru, d-Gal, d-Xyl, and d-Rib) and disaccharide (Mal) complexes of Co(II) were synthesised from nonaqueous solutions using [NEt4]2[CoCl2Br2] or CoCl2 · 6H2O and isolated in the solid state. The purified complexes were characterized by diffuse reflectance, aqueous solution absorbance, CD, FTIR, magnetic susceptibility, EPR, and cyclic voltammetric studies. The complexes synthesised from [NEt4]2[CoCl2Br2] were found to be primarily dinuclear, whereas those synthesised from CoCl2 · 6H2O were found to be di- or tetra-nuclear. The hydrolytic stability of the complexes followed a trend: d-Rib > Mal > d-Glc > d-Xyl > d-Fru ⪢ d-Gal.