1
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He P, Hu MY, Li JH, Qiao TZ, Lu YL, Zhu SF. Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation. Natl Sci Rev 2024; 11:nwad324. [PMID: 38314400 PMCID: PMC10837105 DOI: 10.1093/nsr/nwad324] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/07/2023] [Accepted: 11/06/2023] [Indexed: 02/06/2024] Open
Abstract
Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively, and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.
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Affiliation(s)
- Peng He
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Meng-Yang Hu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Jin-Hong Li
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Tian-Zhang Qiao
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Yi-Lin Lu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Shou-Fei Zhu
- Frontiers Science Center for New Organic Matter, State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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2
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Wandzilak A, Grubel K, Skubi KL, McWilliams SF, Bessas D, Rana A, Hugenbruch S, Dey A, Holland PL, DeBeer S. Mössbauer and Nuclear Resonance Vibrational Spectroscopy Studies of Iron Species Involved in N-N Bond Cleavage. Inorg Chem 2023; 62:18449-18464. [PMID: 37902987 PMCID: PMC10647920 DOI: 10.1021/acs.inorgchem.3c02594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Indexed: 11/01/2023]
Abstract
Diketiminate-supported iron complexes are capable of cleaving the strong triple bond of N2 to give a tetra-iron complex with two nitrides (Rodriguez et al., Science, 2011, 334, 780-783). The mechanism of this reaction has been difficult to determine, but a transient green species was observed during the reaction that corresponds to a potential intermediate. Here, we describe studies aiming to identify the characteristics of this intermediate, using a range of spectroscopic techniques, including Mössbauer spectroscopy, electronic absorption spectroscopy, Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and nuclear resonance vibrational spectroscopy (NRVS) complemented by density functional theory (DFT) calculations. We successfully elucidated the nature of the starting iron(II) species and the bis(nitride) species in THF solution, and in each case, THF breaks up the multiiron species. Various observations on the green intermediate species indicate that it has one N2 per two Fe atoms, has THF associated with it, and has NRVS features indicative of bridging N2. Computational models with a formally diiron(0)-N2 core are most consistent with the accumulated data, and on this basis, a mechanism for N2 splitting is suggested. This work shows the power of combining NRVS, Mössbauer, NMR, and vibrational spectroscopies with computations for revealing the nature of transient iron species during N2 cleavage.
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Affiliation(s)
- Aleksandra Wandzilak
- Max
Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany
- Faculty
of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow 30-059, Poland
| | - Katarzyna Grubel
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Kazimer L. Skubi
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department
of Chemistry, Carleton College, Northfield, Minnesota 55057, United States
| | - Sean F. McWilliams
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Dimitrios Bessas
- European
Synchrotron Radiation Facility, Grenoble F-38043, France
| | - Atanu Rana
- Max
Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany
- School of
Chemical Science, Indian Association for
the Cultivation of Science, Kolkata 700032, India
| | - Stefan Hugenbruch
- Max
Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany
| | - Abhishek Dey
- School of
Chemical Science, Indian Association for
the Cultivation of Science, Kolkata 700032, India
| | - Patrick L. Holland
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany
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3
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Jameei Moghaddam N, Gil-Sepulcre M, Wang JW, Benet-Buchholz J, Gimbert-Suriñach C, Llobet A. Interplay between β-Diimino and β-Diketiminato Ligands in Nickel Complexes Active in the Proton Reduction Reaction. Inorg Chem 2022; 61:16639-16649. [PMID: 36196853 PMCID: PMC9597662 DOI: 10.1021/acs.inorgchem.2c02150] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two Ni complexes are reported with κ4-P2N2 β-diimino (BDI) ligands with the general formula [Ni(XBDI)](BF4)2, where BDI is N-(2-(diphenylphosphaneyl)ethyl)-4-((2-(diphenylphosphaneyl)ethyl)imino)pent-2-en-2-amine and X indicates the substituent in the α-carbon intradiimine position, X = H for 1(BF4)2 and X = Ph for 2(BF4)2. Electrochemical analysis together with UV-vis and NMR spectroscopy in acetonitrile and dimethylformamide (DMF) indicates the conversion of the β-diimino complexes 12+ and 22+ to the negatively charged β-diketiminato (BDK) analogues (1-H)+ and (2-H)+ via deprotonation in DMF. Moreover, further electrochemical and spectroscopy evidence indicates that the one-electron-reduced derivatives 1+ and 2+ can also rapidly evolve to the BDK (1-H)+ and (2-H)+, respectively, via hydrogen gas evolution through a bimolecular homolytic pathway. Finally, both complexes are demonstrated to be active for the proton reduction reaction in DMF at Eapp = -1.8 V vs Fc+/0, being the active species the one-electron-reduced derivative 1-H and 2-H.
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Affiliation(s)
- Navid Jameei Moghaddam
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain.,Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007Tarragona, Spain
| | - Marcos Gil-Sepulcre
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain
| | - Jia-Wei Wang
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain
| | - Jordi Benet-Buchholz
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain
| | - Carolina Gimbert-Suriñach
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain.,Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193Barcelona, Spain
| | - Antoni Llobet
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007Tarragona, Spain.,Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193Barcelona, Spain
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4
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Feng H, Yang D, Mei T, Zhang Y, Wang B, Qu J. Synthesis and Structure of Thiolate‐Bridged Diiron and Dicobalt Complexes Supported by Modified β‐Diketiminate Ligand. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Huajin Feng
- Dalian University of Technology State Key Laboratory of Fine Chemicals CHINA
| | - Dawei Yang
- Dalian University of Technology State Key Laboratory of Fine Chemicals 2# Linggong Road 116024 Dalian CHINA
| | - Tao Mei
- Dalian University of Technology State Key Laboratory of Fine Chemicals CHINA
| | - Yahui Zhang
- Dalian University of Technology State Key Laboratory of Fine Chemicals CHINA
| | - Baomin Wang
- Dalian University of Technology State Key Laboratory of Fine Chemicals CHINA
| | - Jingping Qu
- Dalian University of Technology State Key Laboratory of Fine Chemicals CHINA
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5
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Linford-Wood TG, Mahon MF, Grayson MN, Webster RL. Iron-Catalyzed H/D Exchange of Primary Silanes, Secondary Silanes, and Tertiary Siloxanes. ACS Catal 2022; 12:2979-2985. [PMID: 35433105 PMCID: PMC9007460 DOI: 10.1021/acscatal.2c00224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Indexed: 11/28/2022]
Abstract
![]()
A synthetic
study into the catalytic hydrogen/deuterium (H/D) exchange
of 1° silanes, 2° silanes, and 3° siloxanes is presented,
facilitated by iron-β-diketiminato complexes (1a and 1b). Near-complete H/D exchange is observed for
a variety of aryl- and alkyl-containing hydrosilanes and hydrosiloxanes.
The reaction tolerates alternative hydride source pinacolborane (HBpin),
with quantitative H/D exchange. A synthetic and density functional
theory (DFT) investigation suggests that a monomeric iron-deuteride
is responsible for the H/D exchange.
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Affiliation(s)
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Matthew N. Grayson
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Ruth L. Webster
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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6
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Sang S, Unruh T, Demeshko S, Domenianni LI, van Leest NP, Marquetand P, Schneck F, Würtele C, de Zwart FJ, de Bruin B, González L, Vöhringer P, Schneider S. Photo-Initiated Cobalt-Catalyzed Radical Olefin Hydrogenation. Chemistry 2021; 27:16978-16989. [PMID: 34156122 PMCID: PMC9292329 DOI: 10.1002/chem.202101705] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Indexed: 11/30/2022]
Abstract
Outer-sphere radical hydrogenation of olefins proceeds via stepwise hydrogen atom transfer (HAT) from transition metal hydride species to the substrate. Typical catalysts exhibit M-H bonds that are either too weak to efficiently activate H2 or too strong to reduce unactivated olefins. This contribution evaluates an alternative approach, that starts from a square-planar cobalt(II) hydride complex. Photoactivation results in Co-H bond homolysis. The three-coordinate cobalt(I) photoproduct binds H2 to give a dihydrogen complex, which is a strong hydrogen atom donor, enabling the stepwise hydrogenation of both styrenes and unactivated aliphatic olefins with H2 via HAT.
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Affiliation(s)
- Sier Sang
- Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Tobias Unruh
- Institut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-UniversitätWegelerstrasse 1253117BonnGermany
| | - Serhiy Demeshko
- Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Luis I. Domenianni
- Institut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-UniversitätWegelerstrasse 1253117BonnGermany
| | - Nicolaas P. van Leest
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, Faculty of ChemistryUniversity of ViennaWähringer Straße 171090ViennaAustria
| | - Felix Schneck
- Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Christian Würtele
- Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Felix J. de Zwart
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Bas de Bruin
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of ChemistryUniversity of ViennaWähringer Straße 171090ViennaAustria
| | - Peter Vöhringer
- Institut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-UniversitätWegelerstrasse 1253117BonnGermany
| | - Sven Schneider
- Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
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7
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Hong DH, Ferreira RB, Catalano VJ, García-Serres R, Shearer J, Murray LJ. Access to Metal Centers and Fluxional Hydride Coordination Integral for CO 2 Insertion into [Fe 3(μ-H) 3] 3+ Clusters. Inorg Chem 2021; 60:7228-7239. [PMID: 33900076 DOI: 10.1021/acs.inorgchem.1c00244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CO2 insertion into tri(μ-hydrido)triiron(II) clusters ligated by a tris(β-diketiminate) cyclophane is demonstrated to be balanced by sterics for CO2 approach and hydride accessibility. Time-resolved NMR and UV-vis spectra for this reaction for a complex in which methoxy groups border the pocket of the hydride donor (Fe3H3L2, 4) result in a decreased activation barrier and increased kinetic isotope effect consistent with the reduced sterics. For the ethyl congener Fe3H3L1 (2), no correlation is found between rate and reaction solvent or added Lewis acids, implying CO2 coordination to an Fe center in the mechanism. The estimated hydricity (50 kcal/mol) based on observed H/D exchange with BD3 requires Fe-O bond formation in the product to offset an endergonic CO2 insertion. μ3-hydride coordination is noted to lower the activation barrier for the first CO2 insertion event in DFT calculations.
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Affiliation(s)
- Dae Ho Hong
- Center for Catalysis and Florida Center for Heterocyclic Chemistry, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Ricardo B Ferreira
- Center for Catalysis and Florida Center for Heterocyclic Chemistry, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Vincent J Catalano
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, United States
| | - Ricardo García-Serres
- Université Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249), F-38054 Grenoble, France
| | - Jason Shearer
- Department of Chemistry, Trinity University, San Antonio, Texas 78212, United States
| | - Leslie J Murray
- Center for Catalysis and Florida Center for Heterocyclic Chemistry, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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8
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Ott JC, Wadepohl H, Gade LH. Metalloradical Reactivity, Charge Transfer, and Atom Abstractions in a T-Shaped Iron(I) Complex. Inorg Chem 2021; 60:3927-3938. [DOI: 10.1021/acs.inorgchem.0c03724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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9
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Li G, Gu D, Cao R, Hong S, Liu Y, Liu Y. Highly Catalytically Active High-spin Single-atom Iron Catalyst Supported by Catechol-containing Microporous 2D Polymer. CHEM LETT 2020. [DOI: 10.1246/cl.200416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Guangwen Li
- School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Defa Gu
- School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Rui Cao
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Song Hong
- Center for Instrumental Analysis, Beijing University of Chemical Technology, Chaoyang, Beijing 100029, P. R. China
| | - Yushan Liu
- Trinity School of Durham and Chapel Hill, Durham and Chapel Hill, Durham, NC, 27708, USA
| | - Yuzhou Liu
- School of Chemistry, Beihang University, Beijing 100191, P. R. China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China
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10
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Lutz SA, Hickey AK, Gao Y, Chen CH, Smith JM. Two-State Reactivity in Iron-Catalyzed Alkene Isomerization Confers σ-Base Resistance. J Am Chem Soc 2020; 142:15527-15535. [PMID: 32786744 DOI: 10.1021/jacs.0c07300] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A low-coordinate, high spin (S = 3/2) organometallic iron(I) complex is a catalyst for the isomerization of alkenes. A combination of experimental and computational mechanistic studies supports a mechanism in which alkene isomerization occurs by the allyl mechanism. Importantly, while substrate binding occurs on the S = 3/2 surface, oxidative addition to an η1-allyl intermediate only occurs on the S = 1/2 surface. Since this spin state change is only possible when the alkene substrate is bound, the catalyst has high immunity to typical σ-base poisons due to the antibonding interactions of the high spin state.
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Affiliation(s)
- Sean A Lutz
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Anne K Hickey
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Chun-Hsing Chen
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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11
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Gasperini D, King AK, Coles NT, Mahon MF, Webster RL. Seeking Heteroatom-Rich Compounds: Synthetic and Mechanistic Studies into Iron Catalyzed Dehydrocoupling of Silanes. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01440] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Danila Gasperini
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Andrew K. King
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Nathan T. Coles
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Ruth L. Webster
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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12
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Kephart JA, Mitchell BS, Chirila A, Anderton KJ, Rogers D, Kaminsky W, Velian A. Atomically Defined Nanopropeller Fe 3Co 6Se 8(Ph 2PNTol) 6: Functional Model for the Electronic Metal-Support Interaction Effect and High Catalytic Activity for Carbodiimide Formation. J Am Chem Soc 2019; 141:19605-19610. [PMID: 31770487 DOI: 10.1021/jacs.9b12473] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Atomically defined interfaces that maximize the density of active sites and harness the electronic metal-support interaction are desirable to facilitate challenging multielectron transformations, but their synthesis remains a considerable challenge. We report the rational synthesis of the atomically defined metal chalcogenide nanopropeller Fe3Co6Se8L6 (L = Ph2PNTol) featuring three Fe edge sites, and its ensuing catalytic activity for carbodiimide formation. The complex interaction between the Fe edges and Co6Se8 support, including the interplay between oxidation state, substrate coordination, and metal-support interaction, is probed in detail using chemical and electrochemical methods, extensive single crystal X-ray diffraction, and electronic absorption and Mössbauer spectroscopy.
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Affiliation(s)
- Jonathan A Kephart
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Benjamin S Mitchell
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Andrei Chirila
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Kevin J Anderton
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Dylan Rogers
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Werner Kaminsky
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Alexandra Velian
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
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13
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Hickey AK, Greer SM, Valdez-Moreira JA, Lutz SA, Pink M, DeGayner JA, Harris TD, Hill S, Telser J, Smith JM. A Dimeric Hydride-Bridged Complex with Geometrically Distinct Iron Centers Giving Rise to an S = 3 Ground State. J Am Chem Soc 2019; 141:11970-11975. [PMID: 31283232 DOI: 10.1021/jacs.9b04389] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Structural and spectroscopic characterization of the dimeric iron hydride complex [Ph2B(tBuIm)2FeH]2 reveals an unusual structure in which a tetrahedral iron(II) site (S = 2) is connected to a square planar iron(II) site (S = 1) by two bridging hydride ligands. Magnetic susceptibility reveals strong ferromagnetic coupling between iron centers, with a coupling constant of J = +110(12) cm-1, to give an S = 3 ground state. High-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy confirms this model. A qualitative molecular orbital analysis of the electronic structure, as supported by electronic structure calculations, reveals that the observed spin configuration results from the orthogonal alignment of two geometrically distinct four-coordinate iron fragments held together by highly covalent hydride ligands.
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Affiliation(s)
- Anne K Hickey
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Samuel M Greer
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Juan A Valdez-Moreira
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Sean A Lutz
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Maren Pink
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Jordan A DeGayner
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - T David Harris
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Stephen Hill
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences , Roosevelt University , Chicago , Illinois 60605 , United States
| | - Jeremy M Smith
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , Indiana 47405 , United States
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14
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Kim D, Rahaman SMW, Mercado BQ, Poli R, Holland PL. Roles of Iron Complexes in Catalytic Radical Alkene Cross-Coupling: A Computational and Mechanistic Study. J Am Chem Soc 2019; 141:7473-7485. [PMID: 31025567 PMCID: PMC6953484 DOI: 10.1021/jacs.9b02117] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A growing and useful class of alkene coupling reactions involve hydrogen atom transfer (HAT) from a metal-hydride species to an alkene to form a free radical, which is responsible for subsequent bond formation. Here, we use a combination of experimental and computational investigations to map out the mechanistic details of iron-catalyzed reductive alkene cross-coupling, an important representative of the HAT alkene reactions. We are able to explain several observations that were previously mysterious. First, the rate-limiting step in the catalytic cycle is the formation of the reactive Fe-H intermediate, elucidating the importance of the choice of reductant. Second, the success of the catalytic system is attributable to the exceptionally weak (17 kcal/mol) Fe-H bond, which performs irreversible HAT to alkenes in contrast to previous studies on isolable hydride complexes where this addition was reversible. Third, the organic radical intermediates can reversibly form organometallic species, which helps to protect the free radicals from side reactions. Fourth, the previously accepted quenching of the postcoupling radical through stepwise electron transfer/proton transfer is not as favorable as alternative mechanisms. We find that there are two feasible pathways. One uses concerted proton-coupled electron transfer (PCET) from an iron(II) ethanol complex, which is facilitated because the O-H bond dissociation free energy is lowered by 30 kcal/mol upon metal binding. In an alternative pathway, an O-bound enolate-iron(III) complex undergoes proton shuttling from an iron-bound alcohol. These kinetic, spectroscopic, and computational studies identify key organometallic species and PCET steps that control selectivity and reactivity in metal-catalyzed HAT alkene coupling, and create a firm basis for elucidation of mechanisms in the growing class of HAT alkene cross-coupling reactions.
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Affiliation(s)
- Dongyoung Kim
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - S. M. Wahidur Rahaman
- LCC-CNRS, Université de Toulouse, INPT, 205 Route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Rinaldo Poli
- LCC-CNRS, Université de Toulouse, INPT, 205 Route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
| | - Patrick L. Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
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15
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Hong DH, Murray LJ. Carbon Dioxide Insertion into Bridging Iron Hydrides: Kinetic and Mechanistic Studies. Eur J Inorg Chem 2019; 2019:2146-2153. [PMID: 31787843 PMCID: PMC6884086 DOI: 10.1002/ejic.201801404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Indexed: 11/11/2022]
Abstract
The reduction of CO2 to formic acid by transition metal hydrides is a potential pathway to access reactive C1 compounds. To date, no kinetic study has been reported for insertion of a bridging hydride in a weak-field ligated complex into CO2; such centers have relevance to metalloenzymes that catalyze this reaction. Herein, we report the kinetic study of the reaction of a tri(μ-hydride)triiron(II/II/II) cluster supported by a tris(β-diketimine) cyclophane (1) with CO2 monitored by 1H-NMR and temperature-controlled UV-vis spectroscopy. We found that 1 reacts with CO2 to traverse the reported monoformate (1-CO 2 ) and a diformate complex (1-2CO 2 ) at 298 K in toluene, and ultimately yields the triformate species (1-3CO 2 ) at elevated temperature. The second order rate constant, H/D kinetic isotope effect, ∆H ‡,and ∆S ‡for formation of 1-CO 2 were determined as 8.4(3)×10-4 M-1·s-1, 1.08(9), 11(1) kcal·mol-1, and -3(1)×10 cal·mol-1·K-1, respectively at 298 K. These parameters suggest that CO2 coordination to the iron centers does not coordinate prior to the rate controlling step whereas Fe-H bond cleavage does.
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16
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Cruz TFC, Pereira LCJ, Waerenborgh JC, Veiros LF, Gomes PT. Hydroboration of terminal olefins with pinacolborane catalyzed by new 2-iminopyrrolyl iron(ii) complexes. Catal Sci Technol 2019. [DOI: 10.1039/c8cy02319k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
New Fe(ii) mono(2-iminopyrrolyl) complexes catalyze the hydroboration of terminal olefins with pinacolborane via a borane oxidative addition pathway.
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Affiliation(s)
- Tiago F. C. Cruz
- Centro de Química Estrutural
- Departamento de Engenharia Química
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
| | - Laura C. J. Pereira
- C2TN-Centro de Ciências e Tecnologias Nucleares
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
- Portugal
| | - João C. Waerenborgh
- C2TN-Centro de Ciências e Tecnologias Nucleares
- Instituto Superior Técnico
- Universidade de Lisboa
- 2695-066 Bobadela LRS
- Portugal
| | - Luís F. Veiros
- Centro de Química Estrutural
- Departamento de Engenharia Química
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
| | - Pedro T. Gomes
- Centro de Química Estrutural
- Departamento de Engenharia Química
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
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17
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Ott JC, Wadepohl H, Enders M, Gade LH. Taking Solution Proton NMR to Its Extreme: Prediction and Detection of a Hydride Resonance in an Intermediate-Spin Iron Complex. J Am Chem Soc 2018; 140:17413-17417. [PMID: 30486649 DOI: 10.1021/jacs.8b11330] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Guided by DFT based modeling the chemical shift range of a hydride resonance in the proton nuclear magnetic resonance (NMR) spectrum of the intermediate-spin, square planar iron complex tBu(PNP)Fe-H was predicted and detected as a broad resonance at -3560 ppm (295 K) with a temperature dependent shift of approximately 2000 ppm between 223 and 383 K. The first detection of a metal-bonded hydrogen atom by solution NMR in a complex with a paramagnetic ground state illustrates the interplay of theory and experiment for the characterization of key components in paramagnetic base metal catalysis.
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Affiliation(s)
- Jonas C Ott
- Anorganisch-Chemisches Institut , Universität Heidelberg , Im Neuenheimer Feld 276 , 69120 Heidelberg , Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut , Universität Heidelberg , Im Neuenheimer Feld 276 , 69120 Heidelberg , Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut , Universität Heidelberg , Im Neuenheimer Feld 276 , 69120 Heidelberg , Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut , Universität Heidelberg , Im Neuenheimer Feld 276 , 69120 Heidelberg , Germany
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18
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Pelmenschikov V, Gee LB, Wang H, MacLeod KC, McWilliams SF, Skubi KL, Cramer SP, Holland PL. High-Frequency Fe-H Vibrations in a Bridging Hydride Complex Characterized by NRVS and DFT. Angew Chem Int Ed Engl 2018; 57:9367-9371. [PMID: 29847703 DOI: 10.1002/anie.201804601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Indexed: 11/10/2022]
Abstract
High-spin iron species with bridging hydrides have been detected in species trapped during nitrogenase catalysis, but there are few general methods of evaluating Fe-H bonds in high-spin multinuclear iron systems. An 57 Fe nuclear resonance vibrational spectroscopy (NRVS) study on an Fe(μ-H)2 Fe model complex reveals Fe-H stretching vibrations for bridging hydrides at frequencies greater than 1200 cm-1 . These isotope-sensitive vibrational bands are not evident in infrared (IR) spectra, showing the power of NRVS for identifying hydrides in this high-spin iron system. Complementary density functional theory (DFT) calculations elucidate the normal modes of the rhomboidal iron hydride core.
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Affiliation(s)
| | - Leland B Gee
- Department of Chemistry, University of California, Davis, CA, 95616, USA.,Current Address: Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Hongxin Wang
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - K Cory MacLeod
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA
| | | | - Kazimer L Skubi
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA
| | - Stephen P Cramer
- Department of Chemistry, University of California, Davis, CA, 95616, USA
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19
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Pelmenschikov V, Gee LB, Wang H, MacLeod KC, McWilliams SF, Skubi KL, Cramer SP, Holland PL. High-Frequency Fe-H Vibrations in a Bridging Hydride Complex Characterized by NRVS and DFT. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Leland B. Gee
- Department of Chemistry; University of California; Davis CA 95616 USA
- Current Address: Department of Chemistry; Stanford University; Stanford CA 94305 USA
| | - Hongxin Wang
- Department of Chemistry; University of California; Davis CA 95616 USA
| | - K. Cory MacLeod
- Department of Chemistry; Yale University; New Haven CT 06520 USA
| | | | - Kazimer L. Skubi
- Department of Chemistry; Yale University; New Haven CT 06520 USA
| | - Stephen P. Cramer
- Department of Chemistry; University of California; Davis CA 95616 USA
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20
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Schmidt VA, Kennedy CR, Bezdek MJ, Chirik PJ. Selective [1,4]-Hydrovinylation of 1,3-Dienes with Unactivated Olefins Enabled by Iron Diimine Catalysts. J Am Chem Soc 2018; 140:3443-3453. [PMID: 29414238 DOI: 10.1021/jacs.8b00245] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The selective, intermolecular [1,4]-hydrovinylation of conjugated dienes with unactivated α-olefins catalyzed by α-diimine iron complexes is described. Value-added "skipped" diene products were obtained with exclusive [1,4]-selectivity, and the formation of branched, ( Z)-olefin products was observed with no evidence for alkene isomerization. Mechanistic studies conducted with the well-defined, single-component iron precatalyst (MesDI)Fe(COD) (MesDI = [2,4,6-Me3-C6H2-N═CMe]2); COD = 1,5-cyclooctadiene) provided insights into the origin of the high selectivity. An iron diene complex was identified as the catalyst resting state, and one such isoprene complex, (iPrDI)Fe(η4-C5H8), was isolated and characterized. A combination of single crystal X-ray diffraction, Mößbauer spectroscopy, magnetic measurements, and DFT calculations established that the complex is best described as a high-spin Fe(I) center ( SFe = 3/2) engaged in antiferromagnetic coupling to an α-diimine radical anion ( SDI = -1/2), giving rise to the observed S = 1 ground state. Deuterium-labeling experiments and kinetic analyses of the catalytic reaction provided support for a pathway involving oxidative cyclization of an alkene with the diene complex to generate an iron metallacycle. The observed selectivity can be understood in terms of competing steric interactions in the transition states for oxidative cyclization and subsequent β-hydrogen elimination.
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Affiliation(s)
- Valerie A Schmidt
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - C Rose Kennedy
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Máté J Bezdek
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Paul J Chirik
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
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21
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Manz DH, Duan PC, Dechert S, Demeshko S, Oswald R, John M, Mata RA, Meyer F. Pairwise H 2/D 2 Exchange and H 2 Substitution at a Bimetallic Dinickel(II) Complex Featuring Two Terminal Hydrides. J Am Chem Soc 2017; 139:16720-16731. [PMID: 29037034 DOI: 10.1021/jacs.7b08629] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A compartmental ligand scaffold HL with two β-diketiminato binding sites spanned by a pyrazolate bridge gave a series of dinuclear nickel(II) dihydride complexes M[LNi2(H)2], M = Na (Na·2) and K (K·2), which were isolated after reacting the precursor complex [LNi2(μ-Br)] (1) with MHBEt3 (M = Na and K). Crystallographic characterization showed the two hydride ligands to be directed into the bimetallic pocket, closely interacting with the alkali metal cation. Treatment of K·2 with dibenzo(18-crown-6) led to the separated ion pair [LNi2(H)2][K(DB18C6)] (2[K(DB18C6)]). Reaction of Na·2 or K·2 with D2 was investigated by a suite of 1H and 2H NMR experiments, revealing an unusual pairwise H2/D2 exchange process that synchronously involves both Ni-H moieties without H/D scrambling. A mechanistic picture was provided by DFT calculations which suggested facile recombination of the two terminal hydrides within the bimetallic cleft, with a moderate enthalpic barrier of ∼62 kJ/mol, to give H2 and an antiferromagnetically coupled [LNiI2]- species. This was confirmed by SQUID monitoring during H2 release from solid 2[K(DB18C6)]. Interaction with the Lewis acid cation (Na+ or K+) significantly stabilizes the dihydride core. Kinetic data for the M[L(Ni-H)2] → H2 transition derived from 2D 1H EXSY spectra confirmed first-order dependence of H2 release on M·2 concentration and a strong effect of the alkali metal cation M+. Treating [LNi2(D)2]- with phenylacetylene led to D2 and dinickel(II) complex 3- with a twice reduced styrene-1,2-diyl bridging unit in the bimetallic pocket. Complexes [LNiII2(H)2]- having two adjacent terminal hydrides thus represent a masked version of a highly reactive dinickel(I) core. Storing two reducing equivalents in adjacent metal hydrides that evolve H2 upon substrate binding is reminiscent of the proposed N2 binding step at the FeMo cofactor of nitrogenase, suggesting the use of the present bimetallic scaffold for reductive bioinspired activation of a range of inert small molecules.
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Affiliation(s)
- Dennis-Helmut Manz
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Peng-Cheng Duan
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Rainer Oswald
- Institut für Physikalische Chemie, Universität Göttingen , Tammannstrasse 6, D-37077 Göttingen, Germany
| | - Michael John
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Ricardo A Mata
- Institut für Physikalische Chemie, Universität Göttingen , Tammannstrasse 6, D-37077 Göttingen, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen , Tammannstrasse 4, D-37077 Göttingen, Germany
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22
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Casitas A, Krause H, Lutz S, Goddard R, Bill E, Fürstner A. Ligand Exchange on and Allylic C–H Activation by Iron(0) Fragments: π-Complexes, Allyliron Species, and Metallacycles. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00571] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Alicia Casitas
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Helga Krause
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Sigrid Lutz
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Richard Goddard
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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23
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Arnet NA, McWilliams SF, DeRosha DE, Mercado BQ, Holland PL. Synthesis and Mechanism of Formation of Hydride-Sulfide Complexes of Iron. Inorg Chem 2017; 56:9185-9193. [PMID: 28726395 DOI: 10.1021/acs.inorgchem.7b01230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron-sulfide complexes with hydride ligands provide an experimental precedent for spectroscopically detected hydride species on the iron-sulfur MoFe7S9C cofactor of nitrogenase. In this contribution, we expand upon our recent synthesis of the first iron sulfide hydride complex from an iron hydride and a sodium thiolate ( Arnet, N. A.; Dugan, T. R.; Menges, F. S.; Mercado, B. Q.; Brennessel, W. W.; Bill, E.; Johnson, M. A.; Holland, P. L., J. Am. Chem. Soc. 2015 , 137 , 13220 - 13223 ). First, we describe the isolation of an analogous iron sulfide hydride with a smaller diketiminate supporting ligand, which benefits from easier preparation of the hydride precursor and easier isolation of the product. Second, we describe mechanistic studies on the C-S bond cleavage through which the iron sulfide hydride product is formed. In a key experiment, use of cyclopropylmethanethiolate as the sulfur precursor leads to products from cyclopropane ring opening, implicating an alkyl radical as an intermediate. Combined with the results of isotopic labeling studies, the data are consistent with a mechanism in which homolytic C-S bond cleavage is followed by rebound of the alkyl radical to abstract a hydrogen atom from iron to give the observed alkane and iron-sulfide products.
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Affiliation(s)
- Nicholas A Arnet
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Sean F McWilliams
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Daniel E DeRosha
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06511, United States
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24
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McWilliams SF, Brennan-Wydra E, MacLeod KC, Holland PL. Density Functional Calculations for Prediction of 57Fe Mössbauer Isomer Shifts and Quadrupole Splittings in β-Diketiminate Complexes. ACS OMEGA 2017; 2:2594-2606. [PMID: 28691111 PMCID: PMC5494642 DOI: 10.1021/acsomega.7b00595] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/24/2017] [Indexed: 05/09/2023]
Abstract
The relative ease of Mössbauer spectroscopy and of density functional theory (DFT) calculations encourages the use of Mössbauer parameters as a validation method for calculations, and the use of calculations as a double check on crystallographic structures. A number of studies have proposed correlations between the computationally determined electron density at the iron nucleus and the observed isomer shift, but deviations from these correlations in low-valent iron β-diketiminate complexes encouraged us to determine a new correlation for these compounds. The use of B3LYP/def2-TZVP in the ORCA platform provides an excellent balance of accuracy and speed. We provide here not only this new correlation and a clear guide to its use but also a systematic analysis of the limitations of this approach. We also highlight the impact of crystallographic inaccuracies, DFT model truncation, and spin states, with intent to assist experimentalists to use Mössbauer spectroscopy and calculations together.
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Affiliation(s)
- Sean F McWilliams
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Emma Brennan-Wydra
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - K Cory MacLeod
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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25
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Anderton KJ, Knight BJ, Rheingold AL, Abboud KA, García-Serres R, Murray LJ. Reactivity of hydride bridges in a high-spin [Fe 3(μ-H) 3] 3+ cluster: reversible H 2/CO exchange and Fe-H/B-F bond metathesis. Chem Sci 2017; 8:4123-4129. [PMID: 28603601 PMCID: PMC5443887 DOI: 10.1039/c6sc05583d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/27/2017] [Indexed: 01/08/2023] Open
Abstract
The triiron trihydride complex Fe3H3L (1) [where L3– is a tris(β-diketiminate)cyclophanate] reacts with CO and with BF3·OEt2 to afford (FeICO)2FeII(μ3-H)L (2) and Fe3F3L (3), respectively.
The triiron trihydride complex Fe3H3L (1) [where L3– is a tris(β-diketiminate)cyclophanate] reacts with CO and with BF3·OEt2 to afford (FeICO)2FeII(μ3-H)L (2) and Fe3F3L (3), respectively. Variable-temperature and applied-field Mössbauer spectroscopy support the assignment of two high-spin (HS) iron(i) centers and one HS iron(ii) ion in 2. Preliminary studies support a CO-induced reductive elimination of H2 from 1, rather than CO trapping a species from an equilibrium mixture. This complex reacts with H2 to regenerate 1 under a dihydrogen atmosphere, which represents a rare example of reversible CO/H2 exchange and the first to occur at high-spin metal centers, as well as the first example of a reversible multielectron redox reaction at a designed high-spin metal cluster. The formation of 3 proceeds through a previously unreported net fluoride-for-hydride substitution, and 3 is surprisingly chemically inert to Si–H bonds and points to an unexpectedly large difference between the Fe–F and Fe–H bonds in this high-spin system.
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Affiliation(s)
- Kevin J Anderton
- Center for Catalysis , University of Florida , 214 Leigh Hall P.O. Box 117200 , Gainesville , FL 32611 , USA .
| | - Brian J Knight
- Center for Catalysis , University of Florida , 214 Leigh Hall P.O. Box 117200 , Gainesville , FL 32611 , USA .
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry , University of California San Diego , 9500 Gilman Drive, MC 0358 , La Jolla , CA 92093-0358 , USA
| | - Khalil A Abboud
- Department of Chemistry , University of Florida , 214 Leigh Hall P.O. Box 117200 , Gainesville , FL 32611 , USA
| | - Ricardo García-Serres
- Laboratoire de Chimie de Biologie des Métaux , UMR 5249 , Université Joseph Fourier , Grenoble-1, CNRS-CEA 17 Rue des Martyrs , 38054 Grenoble Cedex 9 , France
| | - Leslie J Murray
- Center for Catalysis , University of Florida , 214 Leigh Hall P.O. Box 117200 , Gainesville , FL 32611 , USA .
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26
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Thompson CV, Arman HD, Tonzetich ZJ. A Pyrrole-Based Pincer Ligand Permits Access to Three Oxidation States of Iron in Organometallic Complexes. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00144] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Vance Thompson
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Hadi D. Arman
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Zachary J. Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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27
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Bellows SM, Arnet NA, Gurubasavaraj PM, Brennessel WW, Bill E, Cundari TR, Holland PL. The Mechanism of N-N Double Bond Cleavage by an Iron(II) Hydride Complex. J Am Chem Soc 2016; 138:12112-23. [PMID: 27598037 PMCID: PMC5499983 DOI: 10.1021/jacs.6b04654] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The use of hydride species for substrate reductions avoids strong reductants, and may enable nitrogenase to reduce multiple bonds without unreasonably low redox potentials. In this work, we explore the N═N bond cleaving ability of a high-spin iron(II) hydride dimer with concomitant release of H2. Specifically, this diiron(II) complex reacts with azobenzene (PhN═NPh) to perform a four-electron reduction, where two electrons come from H2 reductive elimination and the other two come from iron oxidation. The rate law of the H2 releasing reaction indicates that diazene binding occurs prior to H2 elimination, and the negative entropy of activation and inverse kinetic isotope effect indicate that H-H bond formation is the rate-limiting step. Thus, substrate binding causes reductive elimination of H2 that formally reduces the metals, and the metals use the additional two electrons to cleave the N-N multiple bond.
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Affiliation(s)
- Sarina M. Bellows
- Department of Chemistry, University of Rochester, Rochester, NY 14627
| | | | | | | | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr, Germany
| | - Thomas R. Cundari
- Department of Chemistry and CASCaM, University of North Texas, Denton, TX 76203
| | - Patrick L. Holland
- Department of Chemistry, University of Rochester, Rochester, NY 14627
- Department of Chemistry, Yale University, New Haven, CT 06520
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Čorić I, Holland PL. Insight into the Iron-Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands. J Am Chem Soc 2016; 138:7200-11. [PMID: 27171599 PMCID: PMC5508211 DOI: 10.1021/jacs.6b00747] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nitrogenase enzymes are used by microorganisms for converting atmospheric N2 to ammonia, which provides an essential source of N atoms for higher organisms. The active site of the molybdenum-dependent nitrogenase is the unique carbide-containing iron-sulfur cluster called the iron-molybdenum cofactor (FeMoco). On the FeMoco, N2 binding is suggested to occur at one or more iron atoms, but the structures of the catalytic intermediates are not clear. In order to establish the feasibility of different potential mechanistic steps during biological N2 reduction, chemists have prepared iron complexes that mimic various structural aspects of the iron sites in the FeMoco. This reductionist approach gives mechanistic insight, and also uncovers fundamental principles that could be used more broadly for small-molecule activation. Here, we discuss recent results and highlight directions for future research. In one direction, synthetic iron complexes have now been shown to bind N2, break the N-N triple bond, and produce ammonia catalytically. Carbon- and sulfur-based donors have been incorporated into the ligand spheres of Fe-N2 complexes to show how these atoms may influence the structure and reactivity of the FeMoco. Hydrides have been incorporated into synthetic systems, which can bind N2, reduce some nitrogenase substrates, and/or reductively eliminate H2 to generate reduced iron centers. Though some carbide-containing iron clusters are known, none yet have sulfide bridges or high-spin iron atoms like the FeMoco.
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Affiliation(s)
- Ilija Čorić
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Patrick L. Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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Leich V, Spaniol TP, Maron L, Okuda J. Molekulares Calciumhydrid: Dicalciumtrihydrid‐Kation, stabilisiert durch einen neutralen makrocyclischen NNNN‐Liganden. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201600552] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Valeri Leich
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1 52056 Aachen Deutschland
| | - Thomas P. Spaniol
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1 52056 Aachen Deutschland
| | - Laurent Maron
- CNRS, INSA, UPS, UMR 5215, LPCNO Université de Toulouse 135 avenue de Rangueil 31077 Toulouse Frankreich
| | - Jun Okuda
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1 52056 Aachen Deutschland
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30
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Leich V, Spaniol TP, Maron L, Okuda J. Molecular Calcium Hydride: Dicalcium Trihydride Cation Stabilized by a Neutral NNNN-Type Macrocyclic Ligand. Angew Chem Int Ed Engl 2016; 55:4794-7. [DOI: 10.1002/anie.201600552] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Valeri Leich
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
| | - Thomas P. Spaniol
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
| | - Laurent Maron
- CNRS, INSA, UPS, UMR 5215, LPCNO; Université de Toulouse; 135 avenue de Rangueil 31077 Toulouse France
| | - Jun Okuda
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
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Arnet NA, Dugan TR, Menges FS, Mercado BQ, Brennessel WW, Bill E, Johnson MA, Holland PL. Synthesis, Characterization, and Nitrogenase-Relevant Reactions of an Iron Sulfide Complex with a Bridging Hydride. J Am Chem Soc 2015; 137:13220-3. [PMID: 26457740 PMCID: PMC4818001 DOI: 10.1021/jacs.5b06841] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The
FeMoco of nitrogenase is an iron–sulfur cluster with
exceptional bond-reducing abilities. ENDOR studies have suggested
that E4, the state that binds and reduces N2, contains bridging hydrides as part of the active-site iron-sulfide
cluster. However, there are no examples of any isolable iron-sulfide
cluster with a hydride, which would test the feasibility of such a
species. Here, we describe a diiron sulfide hydride complex that is
prepared using a mild method involving C–S cleavage of added
thiolate. Its reactions with nitrogenase substrates show that the
hydride can act as a base or nucleophile and that reduction can cause
the iron atoms to bind N2. These results add experimental
support to hydride-based pathways for nitrogenase.
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Affiliation(s)
- Nicholas A Arnet
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Thomas R Dugan
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Fabian S Menges
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - William W Brennessel
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion , Mülheim an der Ruhr, Germany
| | - Mark A Johnson
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
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32
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Lee Y, Anderton KJ, Sloane FT, Ermert DM, Abboud KA, García-Serres R, Murray LJ. Reactivity of Hydride Bridges in High-Spin [3M-3(μ-H)] Clusters (M = FeII, CoII). J Am Chem Soc 2015; 137:10610-7. [PMID: 26270596 DOI: 10.1021/jacs.5b05204] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The designed [3M-3(μ-H)] clusters (M = Fe(II), Co(II)) Fe3H3L (1-H) and Co3H3L (2-H) [where L(3-) is a tris(β-diketiminate) cyclophane] were synthesized by treating the corresponding M3Br3L complexes with KBEt3H. From single-crystal X-ray analysis, the hydride ligands are sterically protected by the cyclophane ligand, and these complexes selectively react with CO2 over other unsaturated substrates (e.g., CS2, Me3SiCCH, C2H2, and CH3CN). The reaction of 1-H or 2-H with CO2 at room temperature yielded Fe3(OCHO)(H)2L (1-CO2) or Co3(OCHO)(H)2L (2-CO2), respectively, which evidence the differential reactivity of the hydride ligands within these complexes. The analogous reactions at elevated temperatures revealed a distinct difference in the reactivity pattern for 2-H as compared to 1-H; Fe3(OCHO)3L (1-3CO2) was generated from 1-H, while 2-H afforded only 2-CO2.
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Affiliation(s)
- Yousoon Lee
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Kevin J Anderton
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Forrest T Sloane
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - David M Ermert
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Khalil A Abboud
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Ricardo García-Serres
- Université Grenoble Alpes, LCBM/PMB and CEA, iRTSV/CBM/PMB and CNRS, UMR 5249, LCBM/PMB, 38000 Grenoble, France
| | - Leslie J Murray
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
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Huang S, Zhao H, Li X, Wang L, Sun H. Synthesis of [POCOP]-pincer iron and cobalt complexes via Csp3–H activation and catalytic application of iron hydride in hydrosilylation reactions. RSC Adv 2015. [DOI: 10.1039/c5ra00072f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Csp3–H bond activation in pincer ligand (Ph2PO(o-C6H2-(4,6-tBu2)))2CH2 (1) (POCH2OP) was achieved by Fe(PMe3)4 and CoMe(PMe3)4 to afford (POCHOP)Fe(H) (PMe3)2 (2) and (POCHOP)Co(PMe3)2 (4).
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Affiliation(s)
- Shaofeng Huang
- School of Chemistry and Chemical Engineering
- Key Laboratory of Special Functional Aggregated Materials
- Ministry of Education
- Shandong University
- 250199 Jinan
| | - Hua Zhao
- School of Chemistry and Chemical Engineering
- Key Laboratory of Special Functional Aggregated Materials
- Ministry of Education
- Shandong University
- 250199 Jinan
| | - Xiaoyan Li
- School of Chemistry and Chemical Engineering
- Key Laboratory of Special Functional Aggregated Materials
- Ministry of Education
- Shandong University
- 250199 Jinan
| | - Lin Wang
- School of Chemistry and Chemical Engineering
- Key Laboratory of Special Functional Aggregated Materials
- Ministry of Education
- Shandong University
- 250199 Jinan
| | - Hongjian Sun
- School of Chemistry and Chemical Engineering
- Key Laboratory of Special Functional Aggregated Materials
- Ministry of Education
- Shandong University
- 250199 Jinan
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