Assembly of Mn-Containing Unprecedented Selenotungstate Clusters with Photocatalytic H2 Evolution Activity

The reaction of Na2WO4 and Na2SeO3 in the presence of MnCl2 under moderately acidic conditions yielded two unprecedented tungstoselenites: dimeric K2Na10[K2⊂{MnSe4W23O85(H2O)6}]·29H2O (1) and trimeric wheel-shaped K2Na10[K2⊂{Mn3Se7W39O131(OH)20(H2O)2}]·60H2O (2). The assemblies of 1 and 2 are based upon the structure directing effects of SeIV heteroatoms for generating diverse well-defined vacancy selenotungstate precursors during the formation. The polyoxoanion of 1 contains two novel Wells–Dawson-type-like {Se2W11} fragments, which are constructed from novel {SeW4} and {SeW7} species derived from Wells–Dawson-type {α-Se2W14} fragments and one disorder of Mn/W center. The polyoxoanion of 2 exhibits a crown-type structure composed of a [Se6W38O120(OH)18(H2O)2]6– “host” (abbreviated as {Se6W38}) encapsulating SeO32–-modified Mn/W and two K+ “guests”. Remarkably, the crown {Se6W38} shell remains a new type of {Se2W12}-based trimeric aggregate in the polyoxometalates chemistry. The two compounds were charact...