Assembly of a new Keggin polyoxometalate-templated complex using flexible bis(benzimidazole) ligand

A new inorganic–organic hybrid compound [Cu2(L)4(H2O)2](SiW12O40)·8H2O (1) [L = 1,1′-(1,4-butanediyl)bis-1H-benzimidazole] has been hydrothermally synthesized and characterized by IR, elemental analyses, XRD and TG analysis. Compound 1 exhibits a two-dimensional (2D) layer network constructed from metal–organic cations [Cu2(L)4(H2O)2]n4n+. There exist π–π stacking interactions among the benzimidazole rings of the adjacent 2D layers leading to a double-sheet structure. The Keggin-type [SiW12O40]4− anions acting as inorganic templates are sandwiched by the double-sheet structure. There exist hydrogen bonding interactions between [SiW12O40]4− anions and double-sheet layers, which extend the 2D network to a 3D supramolecular framework. The electrochemical behavior and electrocatalysis of compound 1 have been studied.