Revisiting the synthesis of [Mo6(η5-C5Me5)O18]−. X-Ray structural analysis, UV-visible, electrochemical and multinuclear NMR characterization

In methanol, [n-Bu4N][MoCp*O3] reacted with [n-Bu4N]2[Mo4O10(OMe)4Cl2] to yield [n-Bu4N][Mo6Cp*O18] in reasonable yield, thus opening a new route in the synthesis of organometallic derivatives of polyoxometalates. The crystal and molecular structure of [n-Bu4N][Mo6Cp*O18]·Me2CO has been determined by single-crystal X-ray diffraction. The ion [Mo6Cp*O18]– has been thoroughly characterized by multinuclear NMR in solution. The 95Mo and 17O NMR data support the conclusion that the Cp* ligand is a better σ + π donor than the oxo ligand. The complex is electrochemically active and displays three successive one-electron reduction processes.