Two wheel-like polytungstates obtained by incorporation of two {Cu4} clusters and two molybdenum centers in the {W48} wheel

Abstract

Two new {P₈W₄₈} wheel-based compounds, Na₁₂Li₁₆{[Cu(H₂O)]₂[Cu₄(OH)₄(H₂O)₈]₂P₈W₄₈O₁₈₄}·55H₂O (1), and K₄Na₂₄Li₁₀{(MoO₂)₂(P₈W₄₈O₁₈₄)}·61H₂O (2) have been synthesized by a conventional aqueous solution method, and characterized by UV, IR, TG analysis, XPRD, ³¹P NMR, XPS, single-crystal X-ray diffraction analyses, magnetic study and electrochemistry study. In compound 1, a wheel-type {P₈W₄₈} containing two {Cu₄} clusters and two isolated Cu cations results in a 10-Cu-containing polyoxotungstate, which represents the first {P₈W₄₈}-based compound trapping two transition metal (TM) clusters in its inner cavity. Further, the polyoxoanion was connected by Na⁺ and Li⁺ cations into a 3D framework. Compound 2 is a 2-Mo-containing {P₈W₄₈}-based polyoxotungstate. Magnetic study indicates that antiferromagnetic interactions exist in compound 1.