title: N₂reduction and hydrogenation to ammonia by a molecular iron-potassium complex.
abstract: The most common catalyst in the Haber-Bosch process for the hydrogenation of dinitrogen (N(2)) to ammonia (NH(3)) is an iron surface promoted with potassium cations (K(+)), but soluble iron complexes have neither reduced the N-N bond of N(2) to nitride (N(3-)) nor produced large amounts of NH(3) from N(2). We report a molecular iron complex that reacts with N(2) and a potassium reductant to give a complex with two nitrides, which are bound to iron and potassium cations. The product has a Fe(3)N(2) core, implying that three iron atoms cooperate to break the N-N triple bond through a six-electron reduction. The nitride complex reacts with acid and with H(2) to give substantial yields of N(2)-derived ammonia. These reactions, although not yet catalytic, give structural and spectroscopic insight into N(2) cleavage and N-H bond-forming reactions of iron.
authors.affiliation: Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
authors.forename: Meghan M
authors.initials: MM
authors.lastname: Rodriguez
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.forename: William W
authors.initials: WW
authors.lastname: Brennessel
authors.forename: Patrick L
authors.initials: PL
authors.lastname: Holland
mesh_terms: D000143:Acids / Q000737:chemistry; D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D055598:Chemical Phenomena; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry; D006865:Hydrogenation; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D011188:Potassium / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry*; D015204:Spectroscopy, Mossbauer
chemical_list: D000143:Acids; D005290:Ferric Compounds; D005296:Ferrous Compounds; D017680:Potassium Compounds; D000641:Ammonia; D006108:Graphite; D009584:Nitrogen; D011188:Potassium
references.citation: J Phys Chem B. 2006 Sep 14;110(36):17719-35
references.pmid: 16956255
references.citation: J Am Chem Soc. 2004 May 26;126(20):6252-4
references.pmid: 15149221
references.citation: J Am Chem Soc. 2001 Sep 19;123(37):9222-3
references.pmid: 11552855
references.citation: Acc Chem Res. 2009 May 19;42(5):609-19
references.pmid: 19267458
references.citation: Chem Commun (Camb). 2007 Dec 7;(45):4797-9
references.pmid: 18004445
references.citation: Nature. 2004 Feb 5;427(6974):527-30
references.pmid: 14765191
references.citation: Science. 2003 Jul 4;301(5629):76-8
references.pmid: 12843387
references.citation: Nat Chem. 2011 Feb;3(2):120-5
references.pmid: 21258384
references.citation: Angew Chem Int Ed Engl. 2006 Aug 25;45(34):5613-6
references.pmid: 16858715
references.citation: J Am Chem Soc. 2005 Jul 27;127(29):10184-5
references.pmid: 16028926
references.citation: J Am Chem Soc. 2006 Jan 25;128(3):756-69
references.pmid: 16417365
references.citation: J Am Chem Soc. 2005 Sep 7;127(35):12378-86
references.pmid: 16131219
references.citation: Inorg Chem. 2004 May 17;43(10):3306-21
references.pmid: 15132641
references.citation: J Am Chem Soc. 2002 Mar 27;124(12):3012-25
references.pmid: 11902893
references.citation: Chem Rev. 1996 Nov 7;96(7):2983-3012
references.pmid: 11848849
references.citation: Inorg Chem. 2008 Oct 6;47(19):8687-95
references.pmid: 18781730
references.citation: Chem Soc Rev. 2010 Nov;39(11):4044-56
references.pmid: 20571678