Synthesis and characterization of molybdenum and tungsten complexes containing tris(diphenylphosphino)methane (tdppm)

Reaction of tris(diphenylphosphino)methane, (Ph2P)3CH (tdppm) with 1 equivalent of M(CO)3(EtCN)3 (M = Mo 1a, M = W 1b) affords [Mo{η2-(Ph2P)3CH}(CO)3(EtCN)] 2a and [W{η2-(Ph2P)3CH}(CO)3(EtCN)] 2b, respectively. Single crystal structure determinations were performed for complexes 2a and 2b. Both structures adopt a distorted octahedral geometry about Mo and W atoms, with one CO and EtCN group occupying an axial position, while the phosphine ligand and two CO ligands occupy the equatorial positions. To our knowledge this is the first structurally-characterized W complex containing the tdppm ligand.