Synthesis and X-ray crystal structures of two transition metal complexes based on functionalised 1,5-anhydro-2-deoxy-d-galactitol and methyl 2-deoxy-α-d-galactopyranoside

Two new ligands of transition metal cations based on galactose-derived scaffolds were synthesised: 1,5-anhydro-2-deoxy-3,4,6-tri-O-(2-picolyl)-d-galactitol and methyl 2-deoxy-3,4,6-tri-O-(2-picolyl)-α-d-galactopyranoside. These ligands permitted the isolation as single crystals of a Co(II) and a Ni(II) complex, respectively. The structures of both complexes were determined by X-ray crystallography showing a coordination sphere including sugar-bound oxygen atoms. The sugar-derived ligands were found to be in both cases in high energy conformations in the crystal structures of the complexes. These conformations contain an arrangement of sugar-bound oxygen atoms similar to those observed in polyol–metal and carbohydrate–metal complexes.

Graphical abstractWe report two crystal structures of transition metal complexes with ligands based on two galacto pyranoid scaffolds. The coordinating sites are discussed in comparison with those found in carbohydrate–metal and polyol–metal complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide