A new octa-Mn-substituted poly(polyoxotungstate)

Abstract

A novel octa-Mn-substituted silicotungstate (ST) [H₂N(CH₃)₂]₈H₁₉Na₄{[K(H₂O)₄WO₄][SiMn^II₂W₁₀O₃₈]₃}[SiMn^III₂W₁₀O₃₈]·27H₂O (1) has been made by the hydrothermal reaction of the trivacant [A-α-SiW₉O₃₄]¹⁰⁻ ({SiW₉}) building block with Mn²⁺ and Mn⁷⁺ cations in the presence of dimethylamine hydrochloride and systematically characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single crystal X-ray diffraction. 1 is a tetrameric cluster formed by a hexa-Mn^II substituted cyclic trimeric {[K(H₂O)₄WO₄][SiMn^II₂W₁₀O₃₈]₃} unit and a {SiMn^III₂W₁₀O₃₈} fragment via two W–O–Mn^III linkers. Furthermore, its electrochemistry, thermal stability and magnetic properties have been studied.