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Title: Electronic Structures of an [Fe(NNR2 )]+/0/– Redox Series: Ligand Noninnocence and Implications for Catalytic Nitrogen Fixation

Journal Article · · Inorganic Chemistry
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [3];  [3]; ORCiD logo [3]; ORCiD logo [2]; ORCiD logo [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
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The intermediacy of metal–NNH2 complexes has been implicated in the catalytic cycles of several examples of transition-metal-mediated nitrogen (N2) fixation. In this context, we have shown that triphosphine-supported Fe(N2) complexes can be reduced and protonated at the distal N atom to yield Fe(NNH2) complexes over an array of charge and oxidation states. Upon exposure to further H+/e– equivalents, these species either continue down a distal-type Chatt pathway to yield a terminal iron(IV) nitride or instead follow a distal-to-alternating pathway resulting in N–H bond formation at the proximal N atom. To understand the origin of this divergent selectivity, herein we synthesize and elucidate the electronic structures of a redox series of Fe(NNMe2) complexes, which serve as spectroscopic models for their reactive protonated congeners.Using a combination of spectroscopies, in concert with density functional theory and correlated ab initio calculations, we evidence one-electron redox noninnocence of the "NNMe2/ moiety. Specifically, although two closed-shell configurations of the "NNR/ ligand have been commonly considered in the literature-isodiazene and hydrazido(2-)-we provide evidence suggesting that, in their reduced forms, the present iron complexes are best viewed in terms of an open-shell [NNR2i]•- ligand coupled antiferromagnetically to the Fe center. Lastly. this one-electron redox noninnocence resembles that of the classically noninnocent ligand NO and may have mechanistic implications for selectivity in N2 fixation activity.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
National Institutes of Health (NIH); National Science Foundation (NSF)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1558610
Journal Information:
Inorganic Chemistry, Vol. 58, Issue 5; ISSN 0020-1669
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 19 works
Citation information provided by
Web of Science

References (80)

The reduction of ligating dinitrogen to yield a ligating N2H2 moiety journal January 1972
Diazene-N-(di-imide) and hydrazido-(2–)N-(aminoimido) complexes: the addition of acids to dinitrogen complexes journal January 1974
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
The mechanism of the secondary alkylation of dinitrogen and the relationship between structure and reactivity in the alkylation of co-ordinated dinitrogen journal January 1980
Recent advances in the chemistry of nitrogen fixation journal December 1978
Diazene, diazenido, isodiazene and hydrazido complexes journal January 2017
Stepwise conversion of dinitrogen co-ordinated to molybdenum into an amine and an imido-complex. Relevance to the reactions of nitrogenase journal January 1982
Reduction Pathway of End-On Terminally Coordinated Dinitrogen. IV. Geometric, Electronic, and Vibrational Structure of a W(IV) Dialkylhydrazido Complex and Its Two-Electron-Reduced Derivative Undergoing N−N Cleavage upon Protonation journal May 2005
Structural, Spectroscopic, and Kinetic Investigation of the Molybdenum Dialkylhydrazido Complexes [MoBr(NNC 5 H 10 )(dppe) 2 ]Br and [Mo(NNC 5 H 10 )(dppe) 2 ]: Activation Parameters and Revised Mechanism for N−N Cleavage † journal March 2009
Synthesis, Structure, and LLCT Transitions in Terminal Hydrazido(2−) Bipyridine Complexes of Titanium journal August 2007
N–N Bond Cleavage of Mid-Valent Ta(IV) Hydrazido and Hydrazidium Complexes Relevant to the Schrock Cycle for Dinitrogen Fixation journal June 2013
Redox Non-Innocent Behavior of a Terminal Iridium Hydrazido(2−) Triple Bond journal October 2016
Nitrogen Fixation Catalyzed by Transition Metal Complexes: Recent Developments: Nitrogen Fixation Catalyzed by Transition Metal Complexes: Recent Developments journal February 2018
Isolation of an iron-nitrene complex from the dioxygen- and iron porphyrin-dependent oxidation of a hydrazine journal August 1982
Iron porphyrin-nitrene complexes: preparation from 1,1-dialkylhydrazines. Electronic structure from NMR, Moessbauer, and magnetic susceptibility studies and crystal structure of the [tetrakis(p-chlorophenyl)porphyrinato][(2,2,6,6-tetramethyl-1-piperidyl)nitrene]iron complex journal March 1984
N 2 Functionalization at Iron Metallaboratranes journal November 2011
H–H and Si–H Bond Addition to Fe≡NNR 2 Intermediates Derived from N 2 journal March 2013
Dinitrogen Activation at Iron and Cobalt Metallalumatranes journal July 2013
Effects of N 2 Binding Mode on Iron-Based Functionalization of Dinitrogen to Form an Iron(III) Hydrazido Complex journal June 2018
Characterization of an Fe≡N–NH 2 Intermediate Relevant to Catalytic N 2 Reduction to NH 3 journal June 2015
Nitrogen Fixation via a Terminal Fe(IV) Nitride journal October 2017
An Fe-N 2 Complex That Generates Hydrazine and Ammonia via Fe═NNH 2 : Demonstrating a Hybrid Distal-to-Alternating Pathway for N 2 Reduction journal March 2016
Complexes with Nitrogen-Centered Radical Ligands: Classification, Spectroscopic Features, Reactivity, and Catalytic Applications journal November 2013
A Terminal Ni(III)−Imide with Diverse Reactivity Pathways journal August 2005
Three-Coordinate Copper(I) Amido and Aminyl Radical Complexes journal March 2009
Selectivity and Mechanism of Hydrogen Atom Transfer by an Isolable Imidoiron(III) Complex journal June 2011
Catalytic C−H Bond Amination from High-Spin Iron Imido Complexes journal April 2011
Characterization of Iron-Imido Species Relevant for N -Group Transfer Chemistry journal February 2016
A Synthetic Single-Site Fe Nitrogenase: High Turnover, Freeze-Quench 57 Fe Mössbauer Data, and a Hydride Resting State journal January 2016
Catalytic N 2 -to-NH 3 Conversion by Fe at Lower Driving Force: A Proposed Role for Metallocene-Mediated PCET journal February 2017
Fe-Mediated HER vs N 2 RR: Exploring Factors That Contribute to Selectivity in P 3 E Fe(N 2 ) (E = B, Si, C) Catalyst Model Systems journal January 2018
Fe-Mediated Nitrogen Fixation with a Metallocene Mediator: Exploring p K a Effects and Demonstrating Electrocatalysis journal April 2018
Molecular orbital analysis of the metal–hydrazide(2−) bonding in co-ordination chemistry † journal January 1998
Bonding analysis of transition metal NNR end-on complexes and comparison with isoelectronic NNR2 species journal January 2001
Synthesis and direct spectroscopic observation of a 1,1-dialkyldiazene. Infrared and electronic spectrum of N-(2,2,6,6-tetramethylpiperidyl)nitrene journal March 1978
Low-temperature matrix isolation of the 1,1-diazene H2NN. Electronic and infrared characterization journal August 1984
Ground and excited states of isodiazene – an ab initio study journal April 2000
Heme versus Non-Heme Iron-Nitroxyl {FeN(H)O} 8 Complexes: Electronic Structure and Biologically Relevant Reactivity journal February 2014
Electron paramagnetic resonance spectra of 1,1-dialkylhydrazyl radicals in solution journal September 1973
The EPR Spectra of Hydrazyl and Some 1-Substituted Hydrazyl Radicals in Solution journal March 1974
Electron paramagnetic resonance spectroscopic study of radical cations from hydrazine, methylhydrazine, and dimethylhydrazines journal June 1971
Quantitative Geometric Descriptions of the Belt Iron Atoms of the Iron−Molybdenum Cofactor of Nitrogenase and Synthetic Iron(II) Model Complexes journal January 2007
Photolysis of Dimethylcarbamoyl Azide in an Argon Matrix: Spectroscopic Identification of Dimethylamino Isocyanate and 1,1-Dimethyldiazene journal November 2013
A complex of the hydrazidium (N–NH 3 + ) ligand: X-ray structure of [WCl(NNH 3 )(PMe 3 ) 4 ]Cl 2 journal January 1987
Protonation reactions of dinitrogen complexes of molybdenum and tungsten with PMe3 as Co-ligand. X-Ray structure of the hydrazidium complex [WCl(NNH3)(PMe3)4] Cl2 journal January 1990
Synthesis and reactions of monomeric hydrazine and hydrazido complexes that contain the Cp*MoMe3 core journal June 1993
Titanium Hydrazido and Imido Complexes:  Synthesis, Structure, Reactivity, and Relevance to Alkyne Hydroamination journal February 2004
Synthesis, Structures and Reactivity of Group 4 Hydrazido Complexes Supported by Calix[4]arene Ligands journal December 2008
Site selectivity and reversibility in the reactions of titanium hydrazides with Si–H, Si–X, C–X and H+ reagents: TiNα 1,2-silane addition, Nβ alkylation, Nα protonation and σ-bond metathesis journal January 2012
The Cambridge Structural Database
  • Groom, Colin R.; Bruno, Ian J.; Lightfoot, Matthew P.
  • Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials, Vol. 72, Issue 2, p. 171-179 https://doi.org/10.1107/S2052520616003954
journal April 2016
XAS Characterization of a Nitridoiron(IV) Complex with a Very Short Fe−N Bond journal July 2007
An Iron Nitride Complex journal March 2008
Structural and Spectroscopic Characterization of an Electrophilic Iron Nitrido Complex journal August 2008
Mössbauer Spectroscopy and Transition Metal Chemistry: Fundamentals and Applications book January 2011
Spectroscopic Properties and Electronic Structure of Five- and Six-Coordinate Iron(II) Porphyrin NO Complexes:  Effect of the Axial N-Donor Ligand journal April 2006
Vibrational Assignments of Six-Coordinate Ferrous Heme Nitrosyls: New Insight from Nuclear Resonance Vibrational Spectroscopy journal November 2008
Atomic parameters for paramagnetic resonance data journal June 1978
Terminal Iron Dinitrogen and Iron Imide Complexes Supported by a Tris(phosphino)borane Ligand journal January 2011
Excited electronic states of ketene journal May 1976
Copper Corroles: the Question of Noninnocence journal November 2010
Electronic Structure of Selected {FeNO} 7 Complexes in Heme and Non-Heme Architectures: A Density Functional and Multireference ab Initio Study journal January 2010
A Step beyond the Feltham–Enemark Notation: Spectroscopic and Correlated ab Initio Computational Support for an Antiferromagnetically Coupled M(II)–(NO) − Description of Tp*M(NO) (M = Co, Ni) journal November 2011
Structural and Spectroscopic Characterization of a High-Spin {FeNO} 6 Complex with an Iron(IV)−NO − Electronic Structure journal April 2016
Electronic structure analysis of multistate reactivity in transition metal catalyzed reactions: the case of C–H bond activation by non-heme iron(iv)–oxo cores journal January 2013
Ground-state potential energy surface of diazene journal May 1987
Activation of Diazene and the Nitrogenase Problem:  An Investigation of Diazene-Bridged Fe(II) Centers with Sulfur Ligand Sphere. 2. Vibrational Properties journal September 1997
The Reduction Pathway of End-on Coordinated Dinitrogen. I. Vibrational Spectra of Mo/W−N2, −NNH, and −NNH2 Complexes and Quantum Chemistry Assisted Normal Coordinate Analysis journal April 1999
Reduction Pathway of End-On Coordinated Dinitrogen. 3. Electronic Structure and Spectroscopic Properties of Molybdenum/Tungsten Hydrazidium Complexes journal January 2003
Electron spin resonance spectra of some isotopically substituted hydrocarbon radicals journal January 1967
Efficient Nitrogen Fixation via a Redox-Flexible Single-Iron Site with Reverse-Dative Iron → Boron σ Bonding journal April 2018
Evaluating Molecular Cobalt Complexes for the Conversion of N 2 to NH 3 journal May 2015
N–H Bond Dissociation Enthalpies and Facile H Atom Transfers for Early Intermediates of Fe–N 2 and Fe–CN Reductions journal February 2017
Studies Relevant to Catalytic Reduction of Dinitrogen to Ammonia by Molybdenum Triamidoamine Complexes journal February 2005
Reduction Pathway of End-On Terminally Coordinated Dinitrogen. V. N−N Bond Cleavage in Mo/W Hydrazidium Complexes with Diphosphine Coligands. Comparison with Triamidoamine Systems journal May 2005
A bound reaction intermediate sheds light on the mechanism of nitrogenase journal March 2018
Nuclear Resonance Vibrational Spectroscopy Applied to [Fe(OEP)(NO)]: The Vibrational Assignments of Five-Coordinate Ferrous Heme−Nitrosyls and Implications for Electronic Structure journal March 2010
Nuclear resonance vibrational spectroscopy of a protein active-site mimic journal August 2001
Nuclear resonant spectroscopy journal January 2004
SHELXT – Integrated space-group and crystal-structure determination journal January 2015
Crystal structure refinement with SHELXL journal January 2015

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