Hydrothermal syntheses and crystal structures of two organic–inorganic hybrid molybdovanadates based on [V2Mo6(OH)2O24]4− and [VMo12O40]3− polyoxoanions

Abstract

Two new organic–inorganic hybrid cobalt-molybdovanadates [Co(phen)3]H2[H2V2Mo6O26] · 7H2O (1) and [Co(2,2′-bipy)3][Na(H2O)7][VMo12O40] (2) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV, XPS spectroscopy, thermogravimetric (TG) analyses, and X-ray single crystal diffraction. The molecular structure of 1 consists of a [V2Mo6(OH)2O24]4− polyoxoanion, a [Co(phen)3]2+, two H+ and seven lattice water molecules. The structure of [V2Mo6(OH)2O24]4− consists of six MoO6 octahedra and two VO4 tetrahedra; six MoO6 octahedra are linked by edge-sharing oxygens forming a {Mo6} ring, and two VO4 tetrahedra cap opposite sides of the {Mo6} ring. The molecular structural unit of 2 is constructed from a typical Keggin-type [VMo12O40]3− polyoxoanion and a [Co(2,2′-bipy)3]2+ cation and a Na+ countercation; Co2+ is coordinated by six nitrogens from three 2,2′-bipyridines forming a distorted octahedron.