Synthesis and Catalytic Reactivity of Bis(molybdenum-trihalide) Complexes Bridged by Ferrocene Skeleton toward Catalytic Nitrogen Fixation

Bis(molybdenum-trihalide) complexes bearing PNP-type pincer ligand bridged by ferrocene skeleton are synthesized and characterized by X-ray analysis. Ferrocene-linked bis(molybdenum-trihalide) complexes have a lower catalytic activity than do the corresponding mononuclear molybdenum trihalide complexes under the same reaction conditions. The cyclic voltammetry of ferrocene-linked bis(molybdenum-trichloride) complex shows an electronic interaction between the molybdenum and iron centers, but no electronic interaction between the two molybdenum centers is observed in the ferrocene-linked bis(molybdenum-trichloride) complex. Density functional theory calculations indicate no formation of an intramolecular dinitrogen-bridged dimolybdenum structure in the ferrocene-linked bismolybdenum complexes bearing PNP-type pincer ligands.