Multinuclear Er-Containing Polyoxometalate Macrocycle Based on Seleno-Bismutho-Tungstate Fragments

A high-nuclear Er-containing macrocyclic seleno-bismutho-tungstate [H2N(CH3)2]14Cs6H28[Er4(H2O)8{Er3(H2O)9 (SeBiW12O45)2}4]·127H2O (1) has been made by the one-pot assembly reaction of Na2WO4·2H2O, Er(NO3)3·6H2O, Bi(NO3)3·5H2O, Na2SeO3, and dimethylamine hydrochloride in the HOAc-NaOAc buffer solution and structurally characterized. The polyoxoanion of 1 features an octameric assembly [Er4(H2O)8{Er3(H2O)9(SeBiW12O45)2}4]48– composed of four dimeric Er3(H2O)9(SeBiW12O45)2 subunits alternately connected with four ErO6(H2O)2 groups. Notably, the SeBiW12O45 is a brand-new POM fragment formed by two different triangular pyramid heteroatoms, Se and Bi, simultaneously templating tungsten-oxygen groups clustered around them. 1 represents the first example of lanthanide-containing macrocyclic seleno-bismutho-tungstates and the largest bismutho-seleno-tungstate so far. Further, investigations on the catalytic performance show that compound 1 is highly efficient for the selective oxidation of various sulfides.