X-ray Crystal Structure and Characterization of Tetra-vanadyl Capped Highly Reduced Polyoxometalate Anion [PMo5VI MO7V O40 (VIV O)4]2−1

A novel polyoxometalate [H3, O]2 [PMo5VIMo7V O40, (VIV O)4]. 6Py(Py = pyridine) was synthesized and characterized by IR spectrometry, TG and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group (C2/m) with a = 1.3680(3) nm, b = 2.1740(4) nm, c = 1. 1630(2) nm, β = 118.62(3)° V = 3.0362(10) nm3, Z = 2, and R1(wR2) = 0.0772(0.2312). The compound contains a highly reduced vanadylpolymolybdophosphate polyoxometalate anion with a four-capped structure. The four [VO] units cap four opposite pits of the pseudo-Keggin core {PMo12O40}.