1
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Liu HY, Lant HMC, Troiano JL, Hu G, Mercado BQ, Crabtree RH, Brudvig GW. Electrocatalytic, Homogeneous Ammonia Oxidation in Water to Nitrate and Nitrite with a Copper Complex. J Am Chem Soc 2022; 144:8449-8453. [PMID: 35535858 DOI: 10.1021/jacs.2c01788] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrocatalytic ammonia oxidation at room temperature and pressure allows energy-economical and environmentally friendly production of nitrites and nitrates. Few molecular catalysts, however, have been developed for this six- or eight-electron oxidation process. We now report [Cu(bipyalk)]+, a homogeneous electrocatalyst that realizes the title reaction in water at 94% Faradaic efficiency. The catalyst exhibits high selectivity against water oxidation in aqueous media, as [Cu(bipyalk)]+ is not competent for water oxidation.
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Affiliation(s)
- Han-Yu Liu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.,Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Hannah M C Lant
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Jennifer L Troiano
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.,Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Gongfang Hu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.,Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Robert H Crabtree
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.,Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Gary W Brudvig
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.,Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, Connecticut 06516, United States
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2
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Lu Y, Tsegaw YA, Wodyński A, Li L, Beckers H, Kaupp M, Riedel S. Investigation of Molecular Iridium Fluorides IrF
n
(
n
=1–6): A Combined Matrix‐Isolation and Quantum‐Chemical Study. Chemistry 2022; 28:e202104005. [PMID: 35181951 PMCID: PMC9310635 DOI: 10.1002/chem.202104005] [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: 11/06/2021] [Indexed: 12/03/2022]
Abstract
The photo‐initiated defluorination of iridium hexafluoride (IrF6) was investigated in neon and argon matrices at 6 K, and their photoproducts are characterized by IR and UV‐vis spectroscopies as well as quantum‐chemical calculations. The primary photoproducts obtained after irradiation with λ=365 nm are iridium pentafluoride (IrF5) and iridium trifluoride (IrF3), while longer irradiation of the same matrix with λ=278 nm produced iridium tetrafluoride (IrF4) and iridium difluoride (IrF2) by Ir−F bond cleavage or F2 elimination. In addition, IrF5 can be reversed to IrF6 by adding a F atom when exposed to blue‐light (λ=470 nm) irradiation. Laser irradiation (λ=266 nm) of IrF4 also generated IrF6, IrF5, IrF3 and IrF2. Alternatively, molecular binary iridium fluorides IrFn (n=1–6) were produced by co‐deposition of laser‐ablated iridium atoms with elemental fluorine in excess neon and argon matrices under cryogenic conditions. Computational studies up to scalar relativistic CCSD(T)/triple‐ζ level and two‐component quasirelativistic DFT computations including spin‐orbit coupling effects supported the formation of these products and provided detailed insights into their molecular structures by their characteristic Ir−F stretching bands. Compared to the Jahn‐Teller effect, the influence of spin‐orbit coupling dominates in IrF5, leading to a triplet ground state with C4v symmetry, which was spectroscopically detected in solid argon and neon matrices.
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Affiliation(s)
- Yan Lu
- Freie Universität Berlin Institut für Chemie und Biochemie-Anorganische Chemie Fabeckstrasse 34/36 14195 Berlin Germany
| | - Yetsedaw A. Tsegaw
- Freie Universität Berlin Institut für Chemie und Biochemie-Anorganische Chemie Fabeckstrasse 34/36 14195 Berlin Germany
| | - Artur Wodyński
- Technische Universität Berlin Institut für Chemie Theoretische Chemie/Quantenchemie Sekr. C7 Strasse des 17. Juni 135 10623 Berlin Germany
| | - Lin Li
- Freie Universität Berlin Institut für Chemie und Biochemie-Anorganische Chemie Fabeckstrasse 34/36 14195 Berlin Germany
| | - Helmut Beckers
- Freie Universität Berlin Institut für Chemie und Biochemie-Anorganische Chemie Fabeckstrasse 34/36 14195 Berlin Germany
| | - Martin Kaupp
- Technische Universität Berlin Institut für Chemie Theoretische Chemie/Quantenchemie Sekr. C7 Strasse des 17. Juni 135 10623 Berlin Germany
| | - Sebastian Riedel
- Freie Universität Berlin Institut für Chemie und Biochemie-Anorganische Chemie Fabeckstrasse 34/36 14195 Berlin Germany
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3
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Smolobochkin AV, Gazizov AS, Burilov AR, Pudovik MA, Sinyashin OG. Ring opening reactions of nitrogen heterocycles. RUSSIAN CHEMICAL REVIEWS 2019. [DOI: 10.1070/rcr4891] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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4
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Wright AM, Pahls DR, Gary JB, Warner T, Williams JZ, M Knapp SM, Allen KE, Landis CR, Cundari TR, Goldberg KI. Experimental and Computational Investigation of the Aerobic Oxidation of a Late Transition Metal-Hydride. J Am Chem Soc 2019; 141:10830-10843. [PMID: 31259542 DOI: 10.1021/jacs.9b04706] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The rational development of homogeneous catalytic systems for selective aerobic oxidations of organics has been hampered by the limited available knowledge of how oxygen reacts with important organometallic intermediates. Recently, several mechanisms for oxygen insertion into late transition metal-hydride bonds have been described. Contributing to this nascent understanding of how oxygen reacts with metal-hydrides, a detailed mechanistic study of the reaction of oxygen with the IrIII hydride complex (dmPhebox)Ir(OAc)(H) (1) in the presence of acetic acid, which proceeds to form the IrIII complex (dmPhebox)Ir(OAc)2(OH2) (2), is described. The evidence supports a multifaceted mechanism wherein a small amount of an initially formed metal hydroperoxide proceeds to generate a metal-oxyl species that then initiates a radical chain reaction to rapidly convert the remaining IrIII-H. Insight into the initiation step was gained through kinetic and mechanistic studies of the radical chain inhibition by BHT (butylated hydroxytoluene). Computational studies were employed to contribute to a further understanding of initiation and propagation in this system.
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Affiliation(s)
- Ashley M Wright
- Department of Chemistry , University of Washington , Box 351700, Seattle , Washington 98195-1700 , United States
| | - Dale R Pahls
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5017 , United States
| | - J Brannon Gary
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5017 , United States.,Department of Chemistry and Biochemistry , Stephen F. Austin State University , P.O. Box 13006, SFA Station , Nacogdoches , Texas 75962-3006 , United States
| | - Theresa Warner
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5017 , United States
| | - Jacob Z Williams
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5017 , United States
| | - Spring Melody M Knapp
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53719 , United States
| | - Kate E Allen
- Department of Chemistry , University of Washington , Box 351700, Seattle , Washington 98195-1700 , United States
| | - Clark R Landis
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53719 , United States
| | - Thomas R Cundari
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , 1155 Union Circle, #305070 , Denton , Texas 76203-5017 , United States
| | - Karen I Goldberg
- Department of Chemistry , University of Washington , Box 351700, Seattle , Washington 98195-1700 , United States.,Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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5
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Banerjee S, Soldevila-Barreda JJ, Wolny JA, Wootton CA, Habtemariam A, Romero-Canelón I, Chen F, Clarkson GJ, Prokes I, Song L, O'Connor PB, Schünemann V, Sadler PJ. New activation mechanism for half-sandwich organometallic anticancer complexes. Chem Sci 2018; 9:3177-3185. [PMID: 29732100 PMCID: PMC5916112 DOI: 10.1039/c7sc05058e] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 02/18/2018] [Indexed: 01/12/2023] Open
Abstract
The Cp x C-H protons in certain organometallic RhIII half-sandwich anticancer complexes [(η5-Cp x )Rh(N,N')Cl]+, where Cp x = Cp*, phenyl or biphenyl-Me4Cp, and N,N' = bipyridine, dimethylbipyridine, or phenanthroline, can undergo rapid sequential deuteration of all 15 Cp* methyl protons in aqueous media at ambient temperature. DFT calculations suggest a mechanism involving abstraction of a Cp* proton by the Rh-hydroxido complex, followed by sequential H/D exchange, with the Cp* rings behaving like dynamic molecular 'twisters'. The calculations reveal the crucial role of pπ orbitals of N,N'-chelated ligands in stabilizing deprotonated Cp x ligands, and also the accessibility of RhI-fulvene intermediates. They also provide insight into why biologically-inactive complexes such as [(Cp*)RhIII(en)Cl]+ and [(Cp*)IrIII(bpy)Cl]+ do not have activated Cp* rings. The thiol tripeptide glutathione (γ-l-Glu-l-Cys-Gly, GSH) and the activated dienophile N-methylmaleimide, (NMM) did not undergo addition reactions with the proposed RhI-fulvene, although they were able to control the extent of Cp* deuteration. We readily trapped and characterized RhI-fulvene intermediates by Diels-Alder [4+2] cyclo-addition reactions with the natural biological dienes isoprene and conjugated (9Z,11E)-linoleic acid in aqueous media, including cell culture medium, the first report of a Diels-Alder reaction of a metal-bound fulvene in aqueous solution. These findings will introduce new concepts into the design of organometallic Cp* anticancer complexes with novel mechanisms of action.
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Affiliation(s)
- Samya Banerjee
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | | | - Juliusz A Wolny
- Department of Physics , University of Kaiserslautern , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany
| | - Christopher A Wootton
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Abraha Habtemariam
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Isolda Romero-Canelón
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Feng Chen
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Guy J Clarkson
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Ivan Prokes
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Lijiang Song
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Peter B O'Connor
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
| | - Volker Schünemann
- Department of Physics , University of Kaiserslautern , Erwin-Schrödinger-Straße 46 , 67663 Kaiserslautern , Germany
| | - Peter J Sadler
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , UK .
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6
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Zhao M, Zhang XW, Wu CD. Structural Transformation of Porous Polyoxometalate Frameworks and Highly Efficient Biomimetic Aerobic Oxidation of Aliphatic Alcohols. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01985] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Min Zhao
- State Key Laboratory of Silicon Materials, Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Xian-Wei Zhang
- State Key Laboratory of Silicon Materials, Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Chuan-De Wu
- State Key Laboratory of Silicon Materials, Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
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7
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Sinha SB, Shopov DY, Sharninghausen LS, Stein CJ, Mercado BQ, Balcells D, Pedersen TB, Reiher M, Brudvig GW, Crabtree RH. Redox Activity of Oxo-Bridged Iridium Dimers in an N,O-Donor Environment: Characterization of Remarkably Stable Ir(IV,V) Complexes. J Am Chem Soc 2017. [PMID: 28648068 DOI: 10.1021/jacs.7b04874] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Chemical and electrochemical oxidation or reduction of our recently reported Ir(IV,IV) mono-μ-oxo dimers results in the formation of fully characterized Ir(IV,V) and Ir(III,III) complexes. The Ir(IV,V) dimers are unprecedented and exhibit remarkable stability under ambient conditions. This stability and modest reduction potential of 0.99 V vs NHE is in part attributed to complete charge delocalization across both Ir centers. Trends in crystallographic bond lengths and angles shed light on the structural changes accompanying oxidation and reduction. The similarity of these mono-μ-oxo dimers to our Ir "blue solution" water-oxidation catalyst gives insight into potential reactive intermediates of this structurally elusive catalyst. Additionally, a highly reactive material, proposed to be a Ir(V,V) μ-oxo species, is formed on electrochemical oxidation of the Ir(IV,V) complex in organic solvents at 1.9 V vs NHE. Spectroelectrochemistry shows reversible conversion between the Ir(IV,V) and proposed Ir(V,V) species without any degradation, highlighting the exceptional oxidation resistance of the 2-(2-pyridinyl)-2-propanolate (pyalk) ligand and robustness of these dimers. The Ir(III,III), Ir(IV,IV) and Ir(IV,V) redox states have been computationally studied both with DFT and multiconfigurational calculations. The calculations support the stability of these complexes and provide further insight into their electronic structures.
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Affiliation(s)
- Shashi Bhushan Sinha
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Dimitar Y Shopov
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Liam S Sharninghausen
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Christopher J Stein
- Laboratorium für Physikalische Chemie, ETH Zürich , Vladimir-Prelog Weg 2, 8093 Zürich, Switzerland
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - David Balcells
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, N-0315 Oslo, Norway
| | - Thomas Bondo Pedersen
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, N-0315 Oslo, Norway
| | - Markus Reiher
- Laboratorium für Physikalische Chemie, ETH Zürich , Vladimir-Prelog Weg 2, 8093 Zürich, Switzerland
| | - Gary W Brudvig
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Robert H Crabtree
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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8
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Michaelos TK, Shopov DY, Sinha SB, Sharninghausen LS, Fisher KJ, Lant HMC, Crabtree RH, Brudvig GW. A Pyridine Alkoxide Chelate Ligand That Promotes Both Unusually High Oxidation States and Water-Oxidation Catalysis. Acc Chem Res 2017; 50:952-959. [PMID: 28272869 DOI: 10.1021/acs.accounts.6b00652] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Water-oxidation catalysis is a critical bottleneck in the direct generation of solar fuels by artificial photosynthesis. Catalytic oxidation of difficult substrates such as water requires harsh conditions, so the ligand must be designed both to stabilize high oxidation states of the metal center and to strenuously resist ligand degradation. Typical ligand choices either lack sufficient electron donor power or fail to stand up to the oxidizing conditions. Our research on Ir-based water-oxidation catalysts (WOCs) has led us to identify a ligand, 2-(2'-pyridyl)-2-propanoate or "pyalk", that fulfills these requirements. Work with a family of Cp*Ir(chelate)Cl complexes had indicated that the pyalk-containing precursor gave the most robust WOC, which was still molecular in nature but lost the Cp* fragment by oxidative degradation. In trying to characterize the resulting active "blue solution" WOC, we were able to identify a diiridium(IV)-mono-μ-oxo core but were stymied by the extensive geometrical isomerism and coordinative variability. By moving to a family of monomeric complexes [IrIII/IV(pyalk)3] and [IrIII/IV(pyalk)2Cl2], we were able to better understand the original WOC and identify the special properties of the ligand. In this Account, we cover some results using the pyalk ligand and indicate the main features that make it particularly suitable as a ligand for oxidation catalysis. The alkoxide group of pyalk allows for proton-coupled electron transfer (PCET) and its strong σ- and π-donor power strongly favors attainment of exceptionally high oxidation states. The aromatic pyridine ring with its methyl-protected benzylic position provides strong binding and degradation resistance during catalytic turnover. Furthermore, the ligand has two additional benefits: broad solubility in aqueous and nonaqueous solvents and an anisotropic ligand field that enhances the geometry-dependent redox properties of its complexes. After discussion of the general properties, we highlight the specific complexes studied in more detail. In the iridium work, the isolated mononuclear complexes showed easily accessible Ir(III/IV) redox couples, in some cases with the Ir(IV) state being indefinitely stable in water. We were able to rationalize the unusual geometry-dependent redox properties of the various isomers on the basis of ligand-field effects. Even more striking was the isolation and full characterization of a stable Rh(IV) state, for which prior examples were very reactive and poorly characterized. Importantly, we were able to convert monomeric Ir complexes to [Cl(pyalk)2IrIV-O-IrIVCl(pyalk)2] derivatives that help model the "blue solution" properties and provide groundwork for rational synthesis of active, well-defined WOCs. More recent work has moved toward the study of first-row transition metal complexes. Manganese-based studies have highlighted the importance of the chelate effect for labile metals, leading to the synthesis of pincer-type pyalk derivatives. Beyond water oxidation, we believe the pyalk ligand and its derivatives will also prove useful in other oxidative transformations.
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Affiliation(s)
- Thoe K. Michaelos
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Dimitar Y. Shopov
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Shashi Bhushan Sinha
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Liam S. Sharninghausen
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Katherine J. Fisher
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Hannah M. C. Lant
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Robert H. Crabtree
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, 225
Prospect Street, New Haven, Connecticut 06520, United States
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9
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Mindiola DJ. Foreword for the Special Issue “Hydrocarbon Chemistry: Activation and Beyond”. Responsible or Irresponsible Use of Hydrocarbons? You Be the Judge! Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel J. Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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