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Title: Characterization of an Fe≡N–NH 2 intermediate relevant to catalytic N2 reduction to NH3

Journal Article · · Journal of the American Chemical Society
 [1];  [2];  [1];  [1];  [3];  [4];  [2];  [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Northwestern Univ., Evanston, IL (United States); Illinois College, Jacksonville, IL (United States)
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States); Univ. of Nebraska, Lincoln, NE (United States)
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The ability of certain transition metals to mediate the reduction of N2 to NH3 has attracted broad interest in the biological and inorganic chemistry communities. Early transition metals such as Mo and W readily bind N2 and mediate its protonation at one or more N atoms to furnish M(NxHy) species that can be characterized and, in turn, extrude NH3. By contrast, the direct protonation of Fe–N2 species to Fe(NxHy) products that can be characterized has been elusive. In this paper, we show that addition of acid at low temperature to [(TPB)Fe(N2)][Na(12-crown-4)] results in a new S = 1/2 Fe species. EPR, ENDOR, Mössbauer, and EXAFS analysis, coupled with a DFT study, unequivocally assign this new species as [(TPB)Fe≡N–NH2]+, a doubly protonated hydrazido(2–) complex featuring an Fe-to-N triple bond. This unstable species offers strong evidence that the first steps in Fe-mediated nitrogen reduction by [(TPB)Fe(N2)][Na(12-crown-4)] can proceed along a distal or “Chatt-type” pathway. Finally, a brief discussion of whether subsequent catalytic steps may involve early or late stage cleavage of the N–N bond, as would be found in limiting distal or alternating mechanisms, respectively, is also provided.

Research Organization:
California Inst. of Technology, Pasadena, CA (United States); Northwestern Univ., Evanston, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Inst. of Health (NIH) (United States); National Science Foundation (NSF) (United States)
OSTI ID:
1347701
Journal Information:
Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 24 Vol. 137; ISSN 0002-7863
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (57)

Formation of Ammonia from an Iron Nitrido Complex journal April 2009
Transformation of an [Fe(η2-N2H3)]+ Species to π-Delocalized [Fe2(μ-N2H2)]2+/+ Complexes journal March 2011
Terminal Iron Dinitrogen and Iron Imide Complexes Supported by a Tris(phosphino)borane Ligand journal January 2011
Iron–dinitrogen coordination chemistry: Dinitrogen activation and reactivity journal September 2010
ME and ME complexes of iron and cobalt that emphasize three-fold symmetry (E=O, N, NR) journal April 2011
High-Valent Iron(IV)–Oxo Complexes of Heme and Non-Heme Ligands in Oxygenation Reactions journal July 2007
Climbing Nitrogenase: Toward a Mechanism of Enzymatic Nitrogen Fixation journal May 2009
Recent Advances in the Chemistry of Dinitrogen Complexes journal June 1995
The iron-molybdenum cofactor of nitrogenase journal December 1990
Recent advances in the chemistry of nitrogen fixation journal December 1978
Mechanism of Molybdenum Nitrogenase journal January 1996
Structure−Function Relationships of Alternative Nitrogenases journal January 1996
The structural characterization of two isomeric hydrazido(2-) intermediates in the conversion of molybdenum-bound dinitrogen to ammonia and hydrazine journal February 1986
Studies Relevant to Catalytic Reduction of Dinitrogen to Ammonia by Molybdenum Triamidoamine Complexes journal February 2005
Mixed-Valence Dinitrogen-Bridged Fe(0)/Fe(II) Complex journal October 2010
Protonation of the Dinitrogen-Reduction Catalyst [HIPTN 3 N]Mo III Investigated by ENDOR Spectroscopy journal January 2011
Coordination of a Complete Series of N 2 Reduction Intermediates (N 2 H 2 , N 2 H 4 , and NH 3 ) to an Iron Phosphine Scaffold journal October 2011
Metal–Metal Interactions in C 3 -Symmetric Diiron Imido Complexes Linked by Phosphinoamide Ligands journal December 2012
Characterization of an Intermediate in the Ammonia-Forming Reaction of Fe(DMeOPrPE) 2 N 2 with Acid (DMeOPrPE = 1,2-[bis(dimethoxypropyl)phosphino]ethane) journal November 2013
Preparation and properties of dinitrogen-molybdenum complexes. 3. Preparation and molecular structure of 1-(.eta.-hydrazido(2-))fluorobis[1,2-bis(diphenylphosphino)ethane]molybdenum tetrafluoroborate-dichloromethane solvate, [Mo(N2H2)F(Ph2PCH2CH2PPh2)2][BF4].CH2Cl2 journal November 1976
Formation of {[HIPTN 3 N]Mo(III)H} − by Heterolytic Cleavage of H 2 as Established by EPR and ENDOR Spectroscopy journal December 2009
Hydroxylation of Camphor by Reduced Oxy-Cytochrome P450cam:  Mechanistic Implications of EPR and ENDOR Studies of Catalytic Intermediates in Native and Mutant Enzymes journal February 2001
Catalytic Mechanism of Heme Oxygenase through EPR and ENDOR of Cryoreduced Oxy-Heme Oxygenase and Its Asp 140 Mutants journal February 2002
A Low-Spin d 5 Iron Imide:  Nitrene Capture by Low-Coordinate Iron(I) Provides the 4-Coordinate Fe(III) Complex [PhB(CH 2 PPh 2 ) 3 ]Fe⋮N- p -tolyl journal January 2003
A Tetrahedrally Coordinated L 3 Fe−N x Platform that Accommodates Terminal Nitride (Fe IV ⋮N) and Dinitrogen (Fe I −N 2 −Fe I ) Ligands journal May 2004
EPR Study of the Low-Spin [d 3 ; S = 1 / 2 ], Jahn−Teller-Active, Dinitrogen Complex of a Molybdenum Trisamidoamine journal March 2007
Experimental and Theoretical EPR Study of Jahn−Teller-Active [HIPTN 3 N]MoL Complexes (L = N 2 , CO, NH 3 ) journal April 2010
Catalytic C−H Bond Amination from High-Spin Iron Imido Complexes journal April 2011
Synthesis and Electronic Structure Determination of N -Alkyl-Substituted Bis(imino)pyridine Iron Imides Exhibiting Spin Crossover Behavior journal November 2011
A Nonclassical Dihydrogen Adduct of S = 1 / 2 Fe(I) journal October 2011
N 2 Functionalization at Iron Metallaboratranes journal November 2011
Conversion of Fe–NH 2 to Fe–N 2 with release of NH 3 journal December 2012
Catalytic Reduction of N 2 to NH 3 by an Fe–N 2 Complex Featuring a C-Atom Anchor journal January 2014
EPR, ENDOR, and Electronic Structure Studies of the Jahn–Teller Distortion in an Fe V Nitride journal August 2014
A 10 6 -Fold Enhancement in N 2 -Binding Affinity of an Fe 2 (μ-H) 2 Core upon Reduction to a Mixed-Valence Fe II Fe I State journal September 2014
Alkali Metal Control over N–N Cleavage in Iron Complexes journal November 2014
Free H 2 Rotation vs Jahn–Teller Constraints in the Nonclassical Trigonal (TPB)Co–H 2 Complex journal October 2014
Chemistry: Cyclic fixation of nitrogen journal October 1985
Electrosynthesis of ammonia journal October 1985
Catalytic conversion of nitrogen to ammonia by an iron model complex journal September 2013
Recent developments in the homogeneous reduction of dinitrogen by molybdenum and iron journal May 2013
Triggering N2 uptake via redox-induced expulsion of coordinated NH3 and N2 silylation at trigonal bipyramidal iron journal May 2010
A molybdenum complex bearing PNP-type pincer ligands leads to the catalytic reduction of dinitrogen into ammonia journal December 2010
Molybdenum does it again journal January 2011
Structure of the FeFe-cofactor of the iron-only nitrogenase and possible mechanism for dinitrogen reduction journal January 2004
Multimetallic cooperativity in activation of dinitrogen at iron–potassium sites journal January 2014
On the feasibility of N2 fixation via a single-site FeI/FeIV cycle: Spectroscopic studies of FeI(N2)FeI, FeIVN, and related species journal November 2006
Evidence for an alternative nitrogen fixation system in Azotobacter vinelandii. journal December 1980
Terminal Nitrido and Imido Complexes of the late Transition Metals journal March 2009
Comparative Biochemical Characterization of the Iron-Only Nitrogenase and the Molybdenum Nitrogenase from Rhodobacter Capsulatus journal March 1997
Nitrogenase MoFe-Protein at 1.16 A Resolution: A Central Ligand in the FeMo-Cofactor journal September 2002
Catalytic Reduction of Dinitrogen to Ammonia at a Single Molybdenum Center journal July 2003
CHEMISTRY: So That's How It's Done--Maybe journal July 2003
N2 Reduction and Hydrogenation to Ammonia by a Molecular Iron-Potassium Complex journal November 2011
Evidence for Interstitial Carbon in Nitrogenase FeMo Cofactor journal November 2011
Structural models for the metal centers in the nitrogenase molybdenum-iron protein journal September 1992
Synthesis and characterization of cationic iron complexes supported by the neutral ligands NP i -Pr 3 , NArP i -Pr 3 , and NS t -Bu 3 journal April 2005

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Electro- and Solar-Driven Fuel Synthesis with First Row Transition Metal Complexes journal October 2018
Catalytic N 2 -to-NH 3 Conversion by Fe at Lower Driving Force: A Proposed Role for Metallocene-Mediated PCET journal February 2017
Catalytic transformation of dinitrogen into ammonia and hydrazine by iron-dinitrogen complexes bearing pincer ligand journal July 2016
Heterogeneous Fe3 single-cluster catalyst for ammonia synthesis via an associative mechanism journal April 2018
Group 8 Transition Metal-Dinitrogen Complexes book January 2019
Nitrogen Fixation Reaction Derived from Nanostructured Catalytic Materials journal August 2018
Atomic Nb Anchoring on Graphdiyne as a New Potential Electrocatalyst for Nitrogen Fixation: A Computational View journal September 2019
A Triad of Highly Reduced, Linear Iron Nitrosyl Complexes: {FeNO} 8–10 journal August 2016
Direct Transformation of Molecular Dinitrogen into Ammonia Catalyzed by Cobalt Dinitrogen Complexes Bearing Anionic PNP Pincer Ligands journal August 2016
Proton‐Coupled Reduction of an Iron Cyanide Complex to Methane and Ammonia journal September 2016
Redox Non-Innocent Behavior of a Terminal Iridium Hydrazido(2−) Triple Bond journal October 2016
A Triad of Highly Reduced, Linear Iron Nitrosyl Complexes: {FeNO} 8-10 journal August 2016
Direct Transformation of Molecular Dinitrogen into Ammonia Catalyzed by Cobalt Dinitrogen Complexes Bearing Anionic PNP Pincer Ligands journal August 2016
Proton-Coupled Reduction of an Iron Cyanide Complex to Methane and Ammonia journal September 2016
Redox Non-Innocent Behavior of a Terminal Iridium Hydrazido(2−) Triple Bond journal October 2016
Transition Metal Diborides: A New Type of High‐performance Electrocatalysts for Nitrogen Reduction journal May 2019
Nitrogen Reduction to Ammonia on a Biomimetic Mononuclear Iron Centre: Insights into the Nitrogenase Enzyme journal December 2017
Synthesis and Reactivity of Iron- and Cobalt-Dinitrogen Complexes Bearing PSiP-Type Pincer Ligands toward Nitrogen Fixation: Synthesis and Reactivity of Iron- and Cobalt-Dinitrogen Complexes Bearing PSiP-Type Pincer Ligands toward Nitrogen Fixation journal July 2017
Synthesis and Reactivity of Iron- and Cobalt-Dinitrogen Complexes Bearing PSiP-Type Pincer Ligands toward Nitrogen Fixation journal July 2017
Nitrogen Fixation Catalyzed by Transition Metal Complexes: Recent Developments: Nitrogen Fixation Catalyzed by Transition Metal Complexes: Recent Developments journal February 2018
Revisiting mechanistic studies on dinitrogen reduction to ammonia by an iron dinitrogen complex as nitrogenase mimic journal July 2019
N 2 Reduction on Fe‐Based Complexes with Different Supporting Main‐Group Elements: Critical Roles of Anchor and Peripheral Ligands journal October 2018
Nitrogen Reduction to Ammonia on Atomic‐Scale Active Sites under Mild Conditions journal February 2019
Catalytic transformation of dinitrogen into ammonia and hydrazine by iron-dinitrogen complexes bearing pincer ligand journal July 2016
Heterogeneous Fe3 single-cluster catalyst for ammonia synthesis via an associative mechanism journal April 2018
Complexes of ambiphilic ligands: reactivity and catalytic applications journal January 2016
Stepwise N–H bond formation from N 2 -derived iron nitride, imide and amide intermediates to ammonia journal January 2016
Exploring secondary-sphere interactions in Fe–N x H y complexes relevant to N 2 fixation journal January 2017
Cationic silyldiazenido complexes of the Fe(diphosphine) 2 (N 2 ) platform: structural and electronic models for an elusive first intermediate in N 2 fixation journal January 2017
Single transition metal atom embedded into a MoS 2 nanosheet as a promising catalyst for electrochemical ammonia synthesis journal January 2018
Triphos–Fe dinitrogen and dinitrogen–hydride complexes: relevance to catalytic N 2 reductions journal January 2018
Computational screening of a single transition metal atom supported on the C 2 N monolayer for electrochemical ammonia synthesis journal January 2018
Conversion of dinitrogen to ammonia on Ru atoms supported on boron sheets: a DFT study journal January 2019
Facile synthesis of a Ru-dispersed N-doped carbon framework catalyst for electrochemical nitrogen reduction journal January 2020
Support effect boosting the electrocatalytic N 2 reduction activity of Ni 2 P/N,P-codoped carbon nanosheet hybrids journal January 2020
Thermodynamic Stability in Acid Media of FeN 4 -Based Catalytic Sites Used for the Reaction of Oxygen Reduction in PEM Fuel Cells journal January 2017

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