An Unusual Asymmetric Polyoxomolybdate Containing Mixed-Valence Antimony and Its Derivatives: [Sb₄^VSb₂^IIIMo₁₈O₇₃(H₂O)₂]¹²⁻ and {M(H₂O)₂[Sb₄^VSb₂^IIIMo₁₈O₇₃(H₂O)₂]₂}²²⁻ (M = Mn^II, Fe^II, Cu^II or Co^II)

Abstract

A new type of heteropolyanion containing mixed-valence antimony, [Sb₄^VSb₂^IIIMo₁₈O₇₃(H₂O)₂]¹²⁻ (<b>1a</b>), and its four derivatives, {M(H₂O)₂[Sb₄^VSb₂^IIIMo₁₈O₇₃(H₂O)₂]₂}²²⁻ (M = Mn^II, Fe^II, Cu^II, or Co^II) (<b>2a−5a</b>), have been isolated as ammonium salt, and their structures were determined by single-crystal X-ray diffraction. The framework of the polyanion <b>1a</b> displays a curious asymmetric structure, and there exist six types of Sb coordination environments and seven types of {MoO₆} octahedra. The title compounds were also characterized by elemental analyses, IR, UV–vis, Raman spectra, and cyclic voltammogramms.