Synthesis, structures and electrochemical properties of four organic-inorganic hybrid polyoxometalates constructed from polyoxotungstate clusters and transition metal complexes

摘要

Four novel organic-inorganic hybrid compounds [Cu_5 ~I(4,4'-bpy)3(2,2'-bpy)4][BW_(12)O_(40)]·H2O (1), [Ni_(0.5)(2,2'-bpy)_(1.25)][Ni(2,2'-bpy)3][Ni(2,2'-bpy)2(H2O)(SiW_(11)~(VI)W~VO_(40))]-0.5H2O (2), [H2bpy]2[Zn(2,2'-bpy)3]2[Si2W_(18)O_(62)]·1.5-H2O (3) and [Cu~(II)(2,2'-bpy)2]2[SiW_(12)O_(40)]·2H2O (4) (2,2'-bpy = 2,2'-bipyridine, 4,4'-bpy = 4,4'-bipyridine) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, electrochemical measurements and single-crystal X-ray diffraction. Compound (1) is a novel [BW_(12)O_(40)]~(5-) polyoxoanion bisupported by copper(I) coordination cations with mixed 2,2'-bpy and 4,4'-bpy ligands. Compound (2) is constructed from the [SiW_(11)~(VI)W~VO_(40)]~(5-) polyoxoanions supported by [Ni(2,2'-bpy)2]~(2+). Compound (3) is composed of a novel [Si2W_(18)O_(62)]~(8-) cluster and [Zn(2,2'-bpy)3]~(2+) complexes, which held together into a three-dimensional (3D) supra-molecular network through hydrogen-bonding interactions. Compound (4) shows a 2D layer framework constructed from a bisupporting Keggin polyoxoanion cluster and [Cu(2,2'-bpy)2]~(2+) coordination polymer fragments, resulting in 3D networks via supramolecular interactions.