Effect of the Keggin anions on assembly of CuI-bis(tetrazole) thioether complexes containing multinuclear CuI-cluster

In order to investigate the effect of polyoxometalate (POM) on the assembly of transition metal-bis(tetrazole) thioether complexes, three new complexes based on different Keggin anions and multinuclear CuI-cluster [CuI12(bmtr)9(HSiMo12O40)4] (1), [CuI3(bmtr)3(PM12O40)] (M=W for 2; Mo for 3) (bmtr=1,3-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)propane), have been hydrothermally synthesized and characterized by routine physical methods and single crystal X-ray diffraction. In compound 1, two kinds of nanometer-scale tetranuclear subunits linked by [SiMo12O40]4− polyanions assemble a (3, 4)-connected three-dimensional (3D) self-penetrating framework. Compounds 2 and 3 are isostructural, exhibiting a 1D chain with [PW12O40]3−/[PMo12O40]3− polyanions and trinuclear clusters arranging alternately. The distinct structural differences between these POM-based CuI-bmtr complexes of 1 and 2/3 maybe rest on the contrast of Keggin-type polyoxometalate with different central heteroatoms, which have been discussed in detail. In addition, the electrochemical properties of the title complexes have been investigated.