Novel inorganic–organic hybrids constructed from multinuclear copper cluster and Keggin polyanions: from 1D wave-like chain to 2D network

Abstract

Two novel inorganic–organic hybrids constructed from Keggin-type polyanions and multinuclear copper clusters based on 1-H-1,2,3-benzotriazole (HBTA), [Cu^I₈(BTA)₄(HBTA)₈(SiMo₁₂O₄₀)]·2H₂O (1) and [Cu^II₆(OH)₄(BTA)₄(SiW₁₂O₄₀)(H₂O)₆]·6H₂O (2), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric (TG) analyses. In compound 1, eight Cu^I ions were linked by twelve HBTA/BTA ligands to form an octanuclear Cu^I cluster, which is connected by SiMo₁₂O₄₀⁴⁻ anion with two bridging O atoms and two terminal O atoms to construct a one-dimensional (1D) wave-like chain. The octanuclear copper unit represents the maximum subunit linked just by amine ligands in the POMs system. In 2, four BTA ligands linked five Cu^II ions constructing a pentanuclear “porphyrin-like” subunit, which is connected by another Cu^II ion to form a 1D metal–organic band. The SiW₁₂O₄₀⁴⁻polyanions as tetradentate inorganic linkages extend the 1D band into a two-dimensional (2D) network with (8³)₂(8⁵·10) topology. To the best of our knowledge, compounds 1 and 2 represent the first examples of inorganic–organic hybrids based on metal-HBTA multinuclear subunits and polyoxometalates. The photocatalysis and electrochemical properties have been investigated in this paper.