Construction of two novel borotungstates modified by different ligands connected with single/double bridges

Abstract

Two novel organic–inorganic hybrid borotungstates are decorated by two disparate ligands: (H₂bibp)₂[bibp{Cu(bipy)(bibp)}₂{Cu(bipy)Cl}₂{BW₁₂O₄₀}₂]·3H₂O (1) and [{Cu(bipy)₂}{Cu(bipy)(Hbtb)}{BW₁₂O₄₀}] (2) (bipy = 2,2′-bipyridine, bibp = 4,4′-bis(imidazolyl)biphenyl, btb = 1,4-bis(1H-1,2,4-triazol-1-yl)benzene) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, UV-Vis, XRD and single-crystal X-ray diffraction. Compound 1 exhibits an interesting network consisting of two [BW₁₂O₄₀]⁵⁻ ({BW₁₂}) polyoxoanion units linked by two kinds of copper ions to shape a hole structure. Each unit is linked through [bibp{Cu(bipy)(bibp)}₂{Cu(bipy)Cl}₂]⁶⁺ to form a Z-type one-dimensional (1-D) chain by alternating the single/double-bridge connection. Compound 2 is composed of {BW₁₂} polyoxoanions and the [{Cu(bipy)₂}{Cu(bipy)(Hbtb)}]⁵⁺ coordination cation, connected by a {Cu-btb-Cu} single-bridge to generate a novel 1-D network. There are π–π stacking interactions or supramolecular interactions all throughout to construct two-dimensional (2-D) and three-dimensional (3-D) architectures. The photocatalytic properties, electrochemical properties and electrocatalytic activities of these two compounds have been investigated in detail.