Synthesis and X-ray structural characterization of tris(l-glycinato)vanadium(III) and trans-tetraquadichlorovanadium(III) chloride

Despite the importance of VIII in biology, only three VIII complexes of naturally occurring amino acids have been structurally characterized. We report the structure of the first vanadium complex incorporating a glycine ligand, [V(Gly)3] · 2DMSO, which crystallizes in a monoclinic system with space group Cc, a = 8.9186(5) Å, b = 21.5347(9) Å, c = 9.9064(5) Å and β = 110.536(3)°. The X-ray structural data show the central VIII metal octahedrally coordinated by three bidentate glycinato ligands arranged a mer configuration, with both Δ and Λ enantiomers present in the unit cell. The bulk sample was isolated as [V(Gly)3] · DMSO · NaCl. Structural comparisons are made with the corresponding homoleptic glycinato complexes of CoIII, CrIII and NiII. The structure of trans-[V(OH2)4Cl2]Cl · 2H2O has also been re-determined. This latter complex crystallizes in a monoclinic system in the P2(1)/c space group, a = 6.4381(9) Å, b = 6.3843(9) Å, c = 11.7980(17) Å and β = 98.057(2)°. The vanadium atom lies at a crystallographic inversion centre within the distorted octahedron formed by the four water and two chloride ligands.

The synthesis and structure of the first vanadium complex incorporating glycine, mer [VIII(Gly)3] · DMSO, is presented. The structure of trans-[VIII(OH2)4Cl2]Cl · 2H2O has also been re-determined. This latter complex immediately forms upon dissolving the widely used VIII reagent VCl3 in aqueous solution.Figure optionsDownload as PowerPoint slide