Five new multifunctional inorganic–organic hybrids based on Keggin-type polyoxometalates and a 3,5-di(1H-imidazol-1-yl)benzoic acid ligand

Abstract

Five new inorganic–organic hybrid compounds, [Co₂(HDIBA)₂(DIBA)₂(H₂O)₄]·HPW₁₂O₄₀·2H₂O (1), [Ni₂(HDIBA)₂(DIBA)₂(H₂O)₄]·HPW₁₂O₄₀ (2), [Ag(H₂DIBA)₂·PW₁₂O₄₀]·2H₂O (3), [Ag(H₂DIBA)₂·PMo₁₂O₄₀]·2H₂O (4) and [Ag(H₂DIBA)₂·HSiMo₁₂O₄₀]·2H₂O (5) (HDIBA = 3,5-di(1H-imidazol-1-yl)benzoic acid), based on Keggin-type polyoxometalates (POMs) have been synthesized by a hydrothermal method. Their structures were characterized through single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. The discrete units of 1 are further extended into a 3D supramolecular structure by π–π stacking and hydrogen bonding interactions. In compound 2, wavy ladderlike bimetallic chains are linked by hydrogen bonding interactions to form a 3D supramolecular structure, with POMs filling in the cages. In compounds 3–5, POMs act as bidentate inorganic bridging ligands to link [Ag(H₂DIBA)₂]³⁺ into 1D chains. Their cyclic voltammetric behaviors and electrocatalytic properties were studied. Notably, compound 4 exhibits amperometric sensing performance toward BrO₃⁻. The organic dye pollutant removal behaviors of 1–5 were explored. In addition, the antibacterial/antifungal activities and photoluminescence properties of 3–5 were also investigated.