Polyoxometalates–Directed Assembly of Inorganic–Organic Hybrid Compounds with Copper Multinuclear Nano-cluster Based on Flexible Double Tetrazole-based Thioether

Abstract

Two new inorganic–organic hybrid compounds constructed from different polyoxometalates (POMs) and copper multinuclear clusters, [Cu(bmte)(H2Mo8O26)0.5]·3H2O (1) and [Cu3(bmte)3(HSiMo12O40)]·H2O (2) (bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane), have been synthesized under hydrothermal conditions with a flexible double tetrazole-based thioether and characterized by IR, TG and single-crystal X-ray diffraction analyses. In compound 1, two bmte ligands chelate two CuI ions with three N atoms to form a binuclear nano-scale subunit [Cu2(bmte)2]2+, then the binuclear CuI subunits are connected by [Mo8O26]4− anions to build a one dimensional (1D) chain. In compound 2, a trinuclear nano-scale subunit [Cu3(bmte)3]3+ constructed from three CuI ions and three bmte ligands has been obtained, and the adjacent trinuclear subunits are linked by [SiMo12O40]4− anions to form a “zipper” 1D chain. The adjacent chains of the title compounds are ultimately extended into 2D layers by hydrogen bonds between bmte and POMs. The structural difference of the two compounds indicates that the POMs play an important structure-directed role on the final networks. In addition, the electrochemical behavior of 2-modified carbon paste electrode (2-CPE) and its electrocatalytic reduction of nitrite have been discussed.