Synthesis of Tungsten and Molybdenum Carbon Dioxide Complexes

Tungsten and molybdenum eta(2)-CO2 complexes of the form TpM(NO)(L)(eta(2)-CO2), where M = W, Mo, Tp = tris(pyrazolyl)borate, and L = PMe3, 1-methylimidazole, have been synthesized by displacement of an eta(2)-aromatic ligand under elevated CO2 pressure. These complexes have been characterized by single-crystal X-ray diffraction. The eta(2)-CO2 complexes are air stable and resist decomposition in solution. In addition, the molybdenum eta(2)-CO2 complex undergoes chemical reduction of the eta(2)-CO2 ligand to form TpMo (NO) (1-methylimidazole) (CO).