title: Catalytic reduction of dinitrogen to ammonia at well-defined single metal sites.
abstract: Dinitrogen (N2) is reduced to ammonia at room temperature and 1atm with molybdenum catalysts that contain tetradentate [HIPTN3N]3- triamidoamine ligands {[HIPTN3N]3-=[{3,5-(2,4,6-i-Pr3C6H2)2C6H3NCH2CH2}3N]3-, an example being [HIPTN3N]Mo(N2)} in heptane. Slow addition of the proton source ({2,6-lutidinium}{BAr'4}; Ar'=3,5-(CF3)2C6H3) and reductant (decamethyl chromocene) assure a high yield of ammonia (63-65% in four turnovers) versus dihydrogen formation. Numerous X-ray studies, along with isolation and characterization of seven intermediates in the proposed catalytic reaction (under noncatalytic conditions), suggest that N2 is being reduced at a sterically protected, single Mo centre that cycles between states Mo(III), Mo(IV), Mo(V) and Mo(VI).
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. rrs@mit.edu
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schrock
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D001665:Binding Sites; D002384:Catalysis; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D008670:Metals; D000641:Ammonia; D009584:Nitrogen