Organic-Inorganic Hybrid Materials Based on Basket-like {Ca⊂P6Mo18O73} Cages

Four basket-like organic inorganic hybrids, formulated as [{Cu-II(H2O)(2)}{Ca-4(H2O)(4)(HO0.5)(3)(en)(2)}{Ca subset of(P6Mo4Mo14O73)-Mo-V-O-VI}]center dot 7H(2)O (1), (H(4)bth)[{Fe-II(H2O)}{Ca subset of(P6Mo18O73)-O-VI}]center dot 4H(2)O (2), (H(2)bih)(3)[{Cu-II(H2O)(2)}{Ca subset of(P6Mo2Mo16O73)-Mo-V-O-VI}]center dot 2H(2)O (3), (H(2)bib)(3)-[{Fe-II(H2O)(2)}{Ca subset of P6Mo2V (Mo16O73)-O-VI}]center dot 4H(2)O (4), (bth = 1,6-bis-(triazole)hexane; bih = 1,6-bis(imidazol)hexane; bib = 1,4-bis-(imidazole)butane) have been hydrothermally synthesized and fully characterized. Compounds 1-4 contain polyoxoanion [Ca subset of(P6MonMo18-nO73)-Mo-V-O-VI]((6+n)-) (n = 0, 2, or 4) (abbreviated as {P6Mo18O73}) as a basic building block, which is composed of a "basket body" {P2Mo14} unit and a "handle"-liked {P4Mo4} fragment encasing an alkaline-earth metal Ca2+-cation in the cage. Compound 1 exhibits an infrequent 2D layer structure linked by the Cu(H2O)(2) linker and an uncommon tetranudear calcium complex, while compound 2 is 8-connected 2-D layers connected by binuclear {Fe-2(H2O)(3)} segaments, which are observed for the first time as 2-D basket-like assemblies. Compounds 3 and 4 are similar 1D Z-typed chains bonded by M(H2O)(2) units (M = Cu for 3 and Fe for 4). The optical band gaps of 1-4 reveal their semiconductive natures. They exhibit universal highly efficient degradation ability for typical dyes such as methylene blue, methyl orange, and rhodamine B under UV light. The lifetime and catalysis mechanism of the catalysts have been investigated. The compounds also show good bifunctional electrocatalytic behavior for oxidation of amino acids and reduction of NO2-.