Hydrothermal syntheses and crystal structures of two novel inorganic–organic hybrid compounds based on saturated α-Keggin phosphomolybdate clusters

Two novel inorganic–organic hybrid compounds based on α-Keggin {PMo12O40} (PMo12) clusters, [CuI(bim)2]2{[CuII(bim)2]2[PMoVI9MoV3O40]} (1) and [CuI(mim)2]4[PMoVI11MoVO40]·H2O (2) (bim = benzimidazole, mim = 2-methylimidazole), have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR spectrum, PXRD, elemental and TG analyses. Single crystal X-ray diffraction analyses reveal that both the two three-dimension (3D) supramolecular structures include left- and right-handed helical chains formed by modified polyoxometalate (POM) clusters via hydrogen bonds. 1 is an unusual bicapped Keggin compound with two Cu atoms as caps connecting with the POM via four bridging oxygen atoms, respectively. 2 is a tetrasupporting compound based on PMo12 cluster modified by four [CuI(mim)2]+ fragments. Photocatalytic activities of the two compounds have also been investigated in this paper.