title: Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic.
abstract: Although nitrogenase enzymes routinely convert molecular nitrogen into ammonia under ambient temperature and pressure, this reaction is currently carried out industrially using the Haber-Bosch process, which requires extreme temperatures and pressures to activate dinitrogen. Biological fixation occurs through dinitrogen and reduced NxHy species at multi-iron centres of compounds bearing sulfur ligands, but it is difficult to elucidate the mechanistic details and to obtain stable model intermediate complexes for further investigation. Metal-based synthetic models have been applied to reveal partial details, although most models involve a mononuclear system. Here, we report a diiron complex bridged by a bidentate thiolate ligand that can accommodate HN=NH. Following reductions and protonations, HN=NH is converted to NH3 through pivotal intermediate complexes bridged by N2H3(-) and NH2(-) species. Notably, the final ammonia release was effected with water as the proton source. Density functional theory calculations were carried out, and a pathway of biological nitrogen fixation is proposed.
authors.affiliation: State Key Laboratory of Fine Chemicals, School of Pharmaceutical Science and Technology, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Baomin
authors.initials: B
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Dawei
authors.initials: D
authors.lastname: Yang
authors.forename: Peng
authors.initials: P
authors.lastname: Tong
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Zhao
authors.forename: Lun
authors.initials: L
authors.lastname: Luo
authors.forename: Yuhan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Si
authors.initials: S
authors.lastname: Chen
authors.forename: Fang
authors.initials: F
authors.lastname: Cheng
authors.forename: Jingping
authors.initials: J
authors.lastname: Qu
mesh_terms: D000577:Amides / Q000737:chemistry*; D000641:Ammonia / Q000138:chemical synthesis / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D058085:Iron Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D000577:Amides; D001952:Bridged-Ring Compounds; D058085:Iron Compounds; D013438:Sulfhydryl Compounds; D000641:Ammonia; D009591:Nitrogenase