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.

Keywords:

• Cobalt-molybdovanadate
• Hydrothermal synthesis
• Crystal structure
• XPS spectra

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China, the program for New Century Excellent Talents in University of Henan Province, the Foundation of Education Department of Henan Province, and the Natural Science Foundation of Henan Province.