A Missing Member of the Anderson–Evans Family: Synthesis and Characterization of the Trimethylolmethane-Capped {MnMo6O24} Cluster

In this work, the synthesis and structural characterization of the smallest possible member of the family of bis-functionalized {MnMo6O24} Anderson–Evans polyoxometalates (POMs) is reported. The synthesis of the title compound TBA3{[HC(CH2O)3]2MnMo6O18} (1) was accomplished by using trimethylolmethane as the capping unit (TBA: tetra(n-butyl)ammonium, n-Bu4N+). The molecular structure of the organic–inorganic POM gave rise to yet undisclosed 1H-NMR features, which are discussed thoroughly. Single-crystal X-ray diffraction (XRD) analysis revealed a highly regular 3D packing of the polyoxoanions within a matrix of TBA cations. The hybrid POM is of particular interest regarding potential applications in photocatalysis (i.e., hydrogen evolution) and energy storage. Thus, the electrochemical and thermal properties of 1 are also analyzed.