New self-assembly hybrid compounds based on arsenic–vanadium clusters and transition metal mixed-organic-ligand complexes

Abstract

Seven novel compounds based on arsenic–vanadium clusters [Ni(im)(2,2′-bpy)]₂[Ni(im)₂]₂[Ni(2,2′-bpy)][As₈V₁₄O₄₂(H₂O)] (1), [Ni(2,2′-bpy)₃][Ni(im)₂]_0.5[Ni(2,2′-bpy)(im)][As₈V₁₄O₄₂(H₂O)] (1a), [Ni(2,2′-bpy)(phen)][Ni(2,2′-bpy)₂][As₈V₁₄O₄₂(H₂O)]·H₂O (2) and [Ni(2,2′-biim)(2,2′-bpy)₂]₂[As₈V₁₄O₄₂(H₂O)]·6H₂O (3), [Cd(2,2′-bpy)(phen)₂]₂[As₈V₁₄O₄₂(H₂O)]·4H₂O (4), [Cd₄(phen)₄(ox)(H₂O)₆][As₆V₁₅O₄₂(H₂O)]·2H₂O (5) and [Co₂(phen)₄(ox)][H₂As₈V₁₄O₄₂(H₂O)]·(apy)₂·2H₂O (6) (Him = imidazole, phen = 1,10-phenanthroline, 2,2′-biim = 2,2′-biimidazole, apy = 2-aminopyridine) have been synthesized and characterized by IR, UV-vis, XRD, TG, CD spectrum, elemental analysis and single-crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 is the first example of a hybrid compound constructed from polyoxometalates and transition metal mixed-organic-ligand complexes of negatively charged nitrogen-containing ligands and neutral nitrogen-containing ligands. Compound 1a is the first example of a POM supported TMC which is formed via arsenic–metal contact. Compound 2 is a chiral compound which exhibits a novel 1-D triple-chain structure constructed from [As₈V₁₄O₄₂(H₂O)]⁴⁻ clusters, a type of chiral transition metal mixed-organic-ligand complex and a type of chiral transition metal complex. Compounds 3 and 4 are supramolecular compounds which are formed by [As₈V₁₄O₄₂(H₂O)]⁴⁻ clusters and transition metal mixed-organic-ligand complexes, respectively. Compounds 5 and 6 are constructed from arsenic–vanadium clusters and transition metal complexes of nitrogen-containing ligands and oxalic groups. The catalytic properties of compounds 1 and 2–6 have been investigated and we found that the transition metal mixed-organic-ligand complexes have dramatic influences on the catalytic properties of catalysts.