The mixed-valent 10-manganese(III/IV)-containing 36-tungsto-4-arsenate(V), [Mn^III ₆Mn^IV ₄O₄(OH)₁₂(H₂O)₁₂(A-β-AsW₉O₃₄)₄]²²⁻

Abstract

Interaction of the mixed‐valent 12‐manganese coordination complex [MnIII8MnIV4O12(CH3COO)16(H2O)4] with the lacunary 9‐tungstoarsenate(V) [A‐α‐AsW9O34]9− resulted in the 10‐manganese(III/IV)‐containing 36‐tungsto‐4‐arsenate(V), [MnIII6MnIV4O4(OH)12(H2O)12(A‐β‐AsW9O34)4]22− (1). Polyanion 1 was isolated as a hydrated mixed potassium–sodium salt, K14Na8[MnIII6MnIV4O4(OH)12(H2O)12(A‐β‐AsW9O34)4]·104H2O, which crystallizes in the orthorhombic space group Pbcn and was characterized by FT–IR spectroscopy and single‐crystal X‐ray diffraction, as well as elemental and thermogravimetric analyses. The title polyanion contains a unique [MnIII6MnIV4O4(OH)12(H2O)12]14+ core stabilized within the 36‐tungsto‐4‐arsenate(V) framework.

Modified polyoxometalate: a novel monocapped bi-supporting and reduced α-Keggin structure {PMo12O40[Cu(2,2′-bpy)]}[Cu(2,2′-bpy)(en)(H2O)]2

“…Three strategies, i.e. reduction, substitution and lacunarity, were exploited to increase the surface charge density and activate the surface O atoms of a POM, for instance, changing M VI (M = Mo or W) to M V by a strong reducing agent (Han et al, 2014;Salomon et al, 2018;Sha et al, 2007), substituting high-oxidation-state Mo VI by lower oxidation state V IV or Nb V (Guo et al, 2011;Niu et al, 2010;Shen et al, 2014;Yuan et al, 2003), or removing MO 6 octahedra to form lacunary POMs (Al-Oweini et al, 2018;Zheng et al, 2008). Thus, various functionalized 'value-added' Keggin derivatives, such as capped, supported, substituted or extended structures, were self-assembled through incorporating or grafting transition metals, lanthanides, organometallic or organic groups onto the surface of polyoxoanions (Dolbecq et al, 2010;Gumerova & Rompel, 2018;Zhao et al, 2016).…”