Synthesis, characterization and crystal structure of a novel Os(II)-supported tungstoarsenate [HAsW7O28Os(dmso)3]6−

Reaction of tri-lacunary Keggin tungstoarsenate with osmium complex Os(dmso)4Cl2 under mild condition led to the formation of a novel Os (II)-supported tungstoarsenate Na5(NH4)[HAsW7O28Os(dmso)3]·15H2O (1a). Single-crystal X-ray diffraction analysis shows that compound 1a crystallizes in the monoclinic space group P21/c (no. 14) with a=14.9166(12) Å, b=23.6935(19) Å, c=16.5349(14) Å, β=92.7950(10)°, V=5836.9(8) Å3, Z=4 with R1=0.0453. The crystal structure reveals two features: (1) the polyanion [HAsW7O28Os(dmso)3]6− (1) consists of a Os(dmso)3 unit linked to a tungstoarsenate fragment {HAsW7O28} via two Os–O–W bonds and one Os–O–As bond resulting in an assembly with Cs symmetry, which represents a novel mode of Os-coordination to a polyoxoanion framework; (2) 3D architecture assembled by the polyanion 1 and sodium linkers. In addition, the compound 1a was well characterized by the multinuclear NMR (13C, 1H), IR spectroscopy, UV–vis spectroscopy, elemental analysis, and cyclic voltammetry (CV).

Graphical abstractA new tungstoarsenate containing a Os(dmso)3 unit [HAsW7O28Os(dmso)3]6− (1) has been synthesized using [HAsW9O34]8− as polyanion precursor and structurally characterized.Figure optionsDownload full-size imageDownload as PowerPoint slide