Influence of Transition Metal Coordination Nature on the Assembly of Multinuclear Subunits in Polyoxometalates-Based Compounds

Four inorganic-organic hybrids based on Keggin-type polyoxometalate (POM), [Ag-3(bmte)(2)(PMo12O40)] (1), [Cu-3(1)(bmte)(3)(PMo12O40)](2), [Cu-11(bmte)(3)(HPMo12O40)](3), and [Ni(bmte)(3)(HPMo12O40] (4) (bmte = 1,2-bis(I -methyl-5-mercapto- 1,2,3,4-tetrazole)ethane), have been synthesized under hydrothermal conditions by tuning the coordination nature of transition metal (TM) ions. The transformation of coordination modes of TM ions has a crucial influence on the multinuclear structures of this series. In compound 1, binuclear subunits (Ag(l)(2)(bmte)(2)](2+) occur, which is connected by PMo12O403- (PMo12) anions to construct a one-dimensional (ID) chain. Furthermore, these chains are linked by Ag(2) ions acting as fuses to construct a two-dimensional (2D) gridlike sheet. Compound 2 shows trinuclear clusters. [Cu-3(1)(bmte)(3)](3+), which are also connected by PMo12 anions to construct a ID chain. These two neighboring chains arrange like a zipper. Compounds 3 and 4 are isostructural. In compound 3, the metal-organic subunit is a 2D sheet constructed by a series of three-membered circles. The polyoxoanions are sandwiched by these two sheets like a hamburger. The influence of the TM coordination nature on the assembly of multinuelear subunits in POM-based compounds is discussed.