1
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Epping RF, Vesseur D, Zhou M, de Bruin B. Carbene Radicals in Transition-Metal-Catalyzed Reactions. ACS Catal 2023; 13:5428-5448. [PMID: 37123600 PMCID: PMC10127290 DOI: 10.1021/acscatal.3c00591] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/21/2023] [Indexed: 04/08/2023]
Abstract
Discovered as organometallic curiosities in the 1970s, carbene radicals have become a staple in modern-day homogeneous catalysis. Carbene radicals exhibit nucleophilic radical-type reactivity orthogonal to classical electrophilic diamagnetic Fischer carbenes. Their successful catalytic application has led to the synthesis of a myriad of carbo- and heterocycles, ranging from simple cyclopropanes to more challenging eight-membered rings. The field has matured to employ densely functionalized chiral porphyrin-based platforms that exhibit high enantio-, regio-, and stereoselectivity. Thus far the focus has largely been on cobalt-based systems, but interest has been growing for the past few years to expand the application of carbene radicals to other transition metals. This Perspective covers the advances made since 2011 and gives an overview on the coordination chemistry, reactivity, and catalytic application of carbene radical species using transition metal complexes and catalysts.
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Affiliation(s)
- Roel F.J. Epping
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - David Vesseur
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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2
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Ma C, Wang S, Sheng Y, Zhao XL, Xing D, Hu W. Synthesis and Characterization of Donor-Acceptor Iron Porphyrin Carbenes and Their Reactivities in N-H Insertion and Related Three-Component Reaction. J Am Chem Soc 2023; 145:4934-4939. [PMID: 36811995 DOI: 10.1021/jacs.2c12155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Iron porphyrin carbenes (IPCs) have been extensively recognized as the reactive intermediates in various iron porphyrin-catalyzed carbene transfer reactions. While donor-acceptor diazo compounds have been frequently used for such transformations, the structures and reactivities of donor-acceptor IPCs are less explored. To date, no crystal structures of donor-acceptor IPC complexes have been reported, and therefore, the involvement of IPC intermediacy for such transformations lacks direct evidence. Here we report the synthesis and NMR characterization of several donor-acceptor IPC complexes from iron porphyrin and corresponding donor-acceptor diazo compounds. The X-ray crystal structure of an IPC complex derived from a morpholine-substituted diazo amide was obtained. The carbene transfer reactivities of those IPCs were tested by the N-H insertion reactions with aniline or morpholine as well as the three-component reaction with aniline and γ,δ-unsaturated α-keto ester based on electrophilic trapping of an ammonium ylide intermediate. Based on these results, IPCs were identified as the real intermediates for iron porphyrin-catalyzed carbene transfer reactions from donor-acceptor diazo compounds.
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Affiliation(s)
- Chaoqun Ma
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Shang Wang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Yuan Sheng
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Xiao-Li Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Dong Xing
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Wenhao Hu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
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3
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Dong ST, Xu C, Lassalle-Kaiser B. Multiple C-C bond formation upon electrocatalytic reduction of CO 2 by an iron-based molecular macrocycle. Chem Sci 2023; 14:550-556. [PMID: 36741521 PMCID: PMC9847672 DOI: 10.1039/d2sc04729b] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Molecular macrocycles are very promising electrocatalysts for the reduction of carbon dioxide into value-added chemicals. Up to now, most of these catalysts produced only C1 products. We report here that iron phthalocyanine, a commercially available molecule based on earth-abundant elements, can produce light hydrocarbons upon electrocatalytic reduction of CO2 in aqueous conditions and neutral pH. Under applied electrochemical potential, C1 to C4 saturated and unsaturated products are evolved. Isotopic labelling experiments unambiguously show that these products stem from CO2. Control experiments and in situ X-ray spectroscopic analysis show that the molecular catalyst remains intact during catalysis and is responsible for the reaction. On the basis of experiments with alternate substrates, a mechanism is proposed for the C-C bond formation step.
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Affiliation(s)
- Si-Thanh Dong
- Synchrotron SOLEILRoute Départementale 128, l’Orme des Merisiers91190 Saint-AubinFrance
| | - Chen Xu
- Synchrotron SOLEILRoute Départementale 128, l’Orme des Merisiers91190 Saint-AubinFrance
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4
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Ren W, Schulz CE, Shroyer MH, Xu W, Xi S, An P, Guo W, Li J. Electronic Configurations and the Effect of Peripheral Substituents of (Nitrosyl)iron Corroles. Inorg Chem 2022; 61:20385-20396. [DOI: 10.1021/acs.inorgchem.2c03026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Wanjie Ren
- College of Materials Science and Optoelectronic Technology and Chinese Academy of Sciences Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing101408, P. R. China
| | - Charles E. Schulz
- Department of Physics and Astronomy, Knox College, Galesburg, Illinois61401, United States
| | - Mark H. Shroyer
- Department of Physics and Astronomy, Knox College, Galesburg, Illinois61401, United States
| | - Wei Xu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing100049, P. R. China
- RICMASS, Rome International Center for Materials Science Superstripes, Via dei Sabelli 119A, Rome00185, Italy
| | - Shibo Xi
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island, Singapore627833, Singapore
| | - Pengfei An
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing100049, P. R. China
| | - Wenping Guo
- National Energy Center for Coal to Clean Fuels, Synfuels China Co., Ltd., Huairou District, Beijing101400, P. R. China
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology and Chinese Academy of Sciences Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing101408, P. R. China
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5
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Hakey BM, Leary DC, Martinez JC, Darmon JM, Akhmedov NG, Petersen JL, Milsmann C. Carbene Transfer from a Pyridine Dipyrrolide Iron–Carbene Complex: Reversible Migration of a Diphenylcarbene Ligand into an Iron–Nitrogen Bond. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brett M. Hakey
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Dylan C. Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jordan C. Martinez
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jonathan M. Darmon
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Novruz G. Akhmedov
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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6
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Koebke KJ, Pinter TBJ, Pitts WC, Pecoraro VL. Catalysis and Electron Transfer in De Novo Designed Metalloproteins. Chem Rev 2022; 122:12046-12109. [PMID: 35763791 PMCID: PMC10735231 DOI: 10.1021/acs.chemrev.1c01025] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the hallmark advances in our understanding of metalloprotein function is showcased in our ability to design new, non-native, catalytically active protein scaffolds. This review highlights progress and milestone achievements in the field of de novo metalloprotein design focused on reports from the past decade with special emphasis on de novo designs couched within common subfields of bioinorganic study: heme binding proteins, monometal- and dimetal-containing catalytic sites, and metal-containing electron transfer sites. Within each subfield, we highlight several of what we have identified as significant and important contributions to either our understanding of that subfield or de novo metalloprotein design as a discipline. These reports are placed in context both historically and scientifically. General suggestions for future directions that we feel will be important to advance our understanding or accelerate discovery are discussed.
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Affiliation(s)
- Karl J. Koebke
- Department of Chemistry, University of Michigan Ann Arbor, MI 48109 USA
| | | | - Winston C. Pitts
- Department of Chemistry, University of Michigan Ann Arbor, MI 48109 USA
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7
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Stroscio GD, Zhou C, Truhlar DG, Gagliardi L. Multiconfiguration Pair-Density Functional Theory Calculations of Iron(II) Porphyrin: Effects of Hybrid Pair-Density Functionals and Expanded RAS and DMRG Active Spaces on Spin-State Orderings. J Phys Chem A 2022; 126:3957-3963. [PMID: 35674705 DOI: 10.1021/acs.jpca.2c02347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron(II) porphyrins play critical roles in enzymes and synthetic catalysts. Computationally determining the spin-state ordering for even the unsubstituted iron(II) porphyrin (FeP) is challenging due to its large size. Multiconfiguration pair-density functional theory (MC-PDFT), a method capable of accurately capturing correlation with lower cost than comparably accurate methods, was previously used to predict a triplet ground state for FeP across a wide range of active spaces up to (34e, 35o). The purpose of this present MC-PDFT study is to determine the effects of including nonlocal exchange in the energy calculation and of using a larger active space size [DMRG(40e, 42o) and RAS(40, 2, 2; 16, 6, 20)] on the calculated FeP spin-state ordering. The recently developed hybrid MC-PDFT method, which uses a weighted average of the MC-PDFT energy and the energy expectation value of the reference wave function, is applied with a weight of the reference wave function energy of λ. We find that increasing λ stabilizes the quintet relative to the triplets. The hybrid tPBE0 functional (tPBE with λ set to 0.25) consistently predicts a triplet ground state with the quintet lying above by 0.10-0.16 eV, depending on the reference wave function. These values are particularly interesting in light of tPBE0's very strong performance for a diverse set of other systems.
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Affiliation(s)
- Gautam D Stroscio
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Chen Zhou
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
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8
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Balhara R, Jindal G. Does an Enol Pathway Preclude High Stereoselectivity in Iron-Catalyzed Indole C-H Functionalization via Carbene Insertion? J Org Chem 2022; 87:7919-7933. [PMID: 35652604 DOI: 10.1021/acs.joc.2c00573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
C-H functionalization of indoles via Fe carbenoids presents an attractive strategy to obtain biologically important structural motifs. However, obtaining good stereoselectivity with Fe has been a significant challenge. It is unclear whether the low selectivity is due to a radical pathway or an ionic mechanism involving metal-free species. We therefore present a density functional theory (DFT) study of indole alkylation with diazoacetates catalyzed by Fe(ClO4)TMEDA/spirobisoxazoline and myoglobin. We explore three mechanistic pathways: nucleophilic, radical, and oxocarbenium routes. The nucleophilic pathway is the most feasible with the formation of an enol species that tautomerizes to furnish the alkylated indole. While this mechanism is routinely proposed, the stereochemical model has been conspicuously absent until now. We show that the conventionally invoked enol pathway is not responsible for the low enantiomeric excess. The enol intermediate can stay coordinated to the catalyst via different binding sites placing the enol in proximity to the chiral environment and affecting the stereoselective proton transfer. Both the binding strength and the chiral environment are crucial for obtaining high selectivity. Our study provides the much needed insights for the modest-low selectivities of Fe systems and could help in expediting the discovery of an efficient catalytic system. These mechanistic underpinnings could also be applicable to other metal (Rh, Pd, Cu, etc.)-catalyzed X-H insertion reactions.
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Affiliation(s)
- Reena Balhara
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Garima Jindal
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
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9
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Chen X, Cao C, Yang YF, She YB. Computational Insights into Different Regioselectivities in Ir-Porphyrin-Catalyzed C–H Insertion Reaction of Quinoid Carbene. Org Chem Front 2022. [DOI: 10.1039/d1qo01727f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanisms and regioselectivities of Ir-porphyrin-catalyzed C–H insertion reaction of quinoid carbene (QC) were investigated with density functional theory (DFT) calculations. The competing catalytic cycles were identified as the hydrogen-atom...
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10
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Wang H, Liu Y, Su C, Schulz CE, Fan Y, Bian Y, Li J. Perspectives on Ligand Properties of N-Heterocyclic Carbenes in Iron Porphyrin Complexes. Inorg Chem 2021; 61:847-856. [PMID: 34962794 DOI: 10.1021/acs.inorgchem.1c02444] [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
There has been considerable research interest in the ligand nature of N-heterocyclic carbenes (NHCs). In this work, two six-coordinate NHC iron porphyrin complexes [FeII(TTP)(1,3-Me2Imd)2] (TTP = tetratolylporphyrin, 1,3-Me2Imd = 1,3-dimethylimidazol-2-ylidene) and [FeIII(TDCPP)(1,3-Me2Imd)2]ClO4 (TDCPP = 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin) are reported. Single-crystal X-ray characterizations demonstrate that both complexes have strongly ruffled conformations and relatively perpendicular ligand orientations which are forced by the sterically bulky 1,3-Me2Imd NHC ligands. Multitemperature (4.2-300 K) and high magnetic field (0-9 T) Mössbauer and low-temperature (4.0 K) EPR spectroscopies definitely confirmed the low-spin states of [FeII(TTP)(1,3-Me2Imd)2] (S = 0) and [FeIII(TDCPP)(1,3-Me2Imd)2]ClO4 (S = 1/2). The similarity of 1,3-Me2Imd and imidazole, as well as the well-established correlations between the ligand nature and spectroscopic characteristics of [FeII,III(Porph)(L)2]0,+ (Porph: porphyrin; L: planar base ligand) species, allowed direct comparisons between the pair of ligands which revealed for the first time that NHC has a stronger π-acceptor ability than imidazoles, in addition to its very strong σ-donation.
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Affiliation(s)
- Haimang Wang
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Yulong Liu
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Chaorui Su
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Charles E Schulz
- Department of Physics, Knox College, Galesburg, Illinois 61401, United States
| | - Yingying Fan
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Yongzhong Bian
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Jianfeng Li
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
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11
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Hakey BM, Leary DC, Xiong J, Harris CF, Darmon JM, Petersen JL, Berry JF, Guo Y, Milsmann C. High Magnetic Anisotropy of a Square-Planar Iron-Carbene Complex. Inorg Chem 2021; 60:18575-18588. [PMID: 34431660 PMCID: PMC9106389 DOI: 10.1021/acs.inorgchem.1c01860] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among Earth-abundant catalyst systems, iron-carbene intermediates that perform C-C bond forming reactions such as cyclopropanation of olefins and C-H functionalization via carbene insertion are rare. Detailed descriptions of the possible electronic structures for iron-carbene bonds are imperative to obtain better mechanistic insights and enable rational catalyst design. Here, we report the first square-planar iron-carbene complex (MesPDPPh)Fe(CPh2), where [MesPDPPh]2- is the doubly deprotonated form of [2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine]. The compound was prepared via reaction of the disubstituted diazoalkane N2CPh2 with (MesPDPPh)Fe(thf) and represents a rare example of a structurally characterized, paramagnetic iron-carbene complex. Temperature-dependent magnetic susceptibility measurements and applied-field Mössbauer spectroscopic studies revealed an orbitally near-degenerate S = 1 ground state with large unquenched orbital angular momentum resulting in high magnetic anisotropy. Spin-Hamiltonian analysis indicated that this S = 1 spin system has uniaxial magnetic properties arising from a ground MS = ±1 non-Kramers doublet that is well-separated from the MS = 0 sublevel due to very large axial zero-field splitting (D = -195 cm-1, E/D = 0.02 estimated from magnetic susceptibility data). This remarkable electronic structure gives rise to a very large, positive magnetic hyperfine field of more than +60 T for the 57Fe nucleus along the easy magnetization axis observed by Mössbauer spectroscopy. Computational analysis with complete active space self-consistent field (CASSCF) calculations provides a detailed electronic structure analysis and confirms that (MesPDPPh)Fe(CPh2) exhibits a multiconfigurational ground state. The majority contribution originates from a configuration best described as a singlet carbene coordinated to an intermediate-spin FeII center with a (dxy)2{(dxz),(dz2)}3(dyz)1(dx2-y2)0 configuration featuring near-degenerate dxz and dz2 orbitals.
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Affiliation(s)
- Brett M Hakey
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Dylan C Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jin Xiong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Caleb F Harris
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jonathan M Darmon
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jeffrey L Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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12
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Arnett CH, Oyala PH, Agapie T. Probing Redox Non‐Innocence in Iron–Carbene Complexes {Fe=C(H)Ar}
10–11
by
1,2
H and
13
C Pulse Electron Paramagnetic Resonance. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Charles H. Arnett
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
| | - Paul H. Oyala
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
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13
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Arnett CH, Oyala PH, Agapie T. Probing Redox Non-Innocence in Iron-Carbene Complexes {Fe=C(H)Ar} 10-11 by 1,2 H and 13 C Pulse Electron Paramagnetic Resonance. Angew Chem Int Ed Engl 2021; 60:27220-27224. [PMID: 34695278 DOI: 10.1002/anie.202110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Indexed: 11/06/2022]
Abstract
We report the synthesis and spectroscopic characterization of a series of iron-carbene complexes in redox states {Fe=C(H)Ar}10-11 . Pulse EPR studies of the 1,2 H and 13 C isotopologues of {Fe=C(H)Ar}11 reveal the high covalency of the Fe-carbene bonding, leading to a more even spin distribution than commonly observed for reduced Fischer carbenes.
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Affiliation(s)
- Charles H Arnett
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
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14
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Zhao J, Qian F, Guo W, Li J, Lin Z. Linkage Isomers of 4-Methylimidazolate Mn(II) Porphyrinates: Hindered or Unhindered? Inorg Chem 2021; 60:7465-7474. [PMID: 33947188 DOI: 10.1021/acs.inorgchem.1c00755] [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
Three different manganese(II) porphyrins have been exploited to react with 4-methylimidazolate (4-MeIm-), and the five-coordinate products are characterized by ultraviolet-visible, single-crystal X-ray, and electronic paramagnetic resonance spectroscopies. Interestingly, 4-MeIm- is found to bond to the metal center through either of the two N atoms (N1 or N3), which yielded two linkage isomers with either an unhindered or a hindered ligand conformation, respectively. Investigations revealed it is the large metal out-of-plane displacements (Δ24 and Δ4 ≥ 0.59 Å) that have rendered the equivalence of two isomers with a small energy difference (5.2-8.3 kJ/mol). The nonbonded intra- and intermolecular interactions thus become crucial factors in the balance of linkage isomerization. All of the products in both solution and solid states show the same characteristic resonances of high-spin Mn(II) (S = 5/2) with g⊥ ≈ 5.9 and g∥ ≈ 2.0 at 4 K, consistent with the weak effects of the axial ligand on core conformation and metal electronic configurations. Zero-field splitting parameters obtained through simulations are also reported.
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Affiliation(s)
- Jianping Zhao
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Fei Qian
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
| | - Wenping Guo
- National Energy Center for Coal to Liquids, Synfuels China Company, Ltd., Beijing 101400, China
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Zeyuan Lin
- The University of Chinese Academy of Sciences, Beijing 100049, China
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15
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Musselman BW, Lehnert N. Bridging and axial carbene binding modes in cobalt corrole complexes: effect on carbene transfer. Chem Commun (Camb) 2020; 56:14881-14884. [PMID: 33174882 DOI: 10.1039/d0cc07073d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Catalytically relevant intermediates in carbene transfer reactions from a diazo precursor were investigated using cobalt corrole complexes. Two divergent mechanisms are proposed depending on the oxidation state of the cobalt center. Mechanistically driven factors for the usage of cobalt corroles in carbene transfer reactions are discussed.
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Affiliation(s)
- Bradley W Musselman
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.
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16
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N–H insertion reaction via an iron carbenoid from α-diazophenylpropionate and its application to the formal total synthesis of stizolobinic acid. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Casali E, Gallo E, Toma L. An In-Depth Computational Study of Alkene Cyclopropanation Catalyzed by Fe(porphyrin)(OCH 3) Complexes. The Environmental Effects on the Energy Barriers. Inorg Chem 2020; 59:11329-11336. [PMID: 32799510 PMCID: PMC8009515 DOI: 10.1021/acs.inorgchem.0c00912] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron porphyrin methoxy complexes, of the general formula [Fe(porphyrin)(OCH3)], are able to catalyze the reaction of diazo compounds with alkenes to give cyclopropane products with very high efficiency and selectivity. The overall mechanism of these reactions was thoroughly investigated with the aid of a computational approach based on density functional theory calculations. The energy profile for the processes catalyzed by the oxidized [FeIII(Por)(OCH3)] (Por = porphine) as well as the reduced [FeII(Por)(OCH3)]- forms of the iron porphyrin was determined. The main reaction step is the same in both of the cases, that is, the one leading to the terminal-carbene intermediate [Fe(Por)(OCH3)(CHCO2Et)] with simultaneous dinitrogen loss; however, the reduced species performs much better than the oxidized one. Contrarily to the iron(III) profile in which the carbene intermediate is directly obtained from the starting reactant complex, the favored iron(II) process is more intricate. The initially formed reactant adduct between [FeII(Por)(OCH3)]- and ethyl diazoacetate (EDA) is converted into a closer reactant adduct, which is in turn converted into the terminal iron porphyrin carbene [Fe(Por)(OCH3)(CHCO2Et)]-. The two corresponding transition states are almost isoenergetic, thus raising the question of whether the rate-determining step corresponds to dinitrogen loss or to the previous structural and electronic rearrangement. The ethylene addition to the terminal carbene is a downhill process, which, on the open-shell singlet surface, presents a defined but probably short-living diradicaloid intermediate, though other spin-state surfaces do not show this intermediate allowing a direct access to the cyclopropane product. For the crucial stationary points, the more complex catalyst [Fe(2)(OCH3)], in which a sterically hindered chiral bulk is mounted onto the porphyrin, was investigated. The corresponding computational data disclose the very significant effect of the porphyrin skeleton on the reaction energy profile. Though the geometrical features around the reactive core of the system remain unchanged, the energy barriers become much lower, thus revealing the profound effects that can be exerted by the three-dimensional organic scaffold surrounding the reaction site.
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Affiliation(s)
- Emanuele Casali
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Emma Gallo
- Dipartimento di Chimica, Università di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Lucio Toma
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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18
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Stroscio GD, Srnec M, Hadt RG. Multireference Ground and Excited State Electronic Structures of Free- versus Iron Porphyrin-Carbenes. Inorg Chem 2020; 59:8707-8715. [PMID: 32510941 DOI: 10.1021/acs.inorgchem.0c00249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron porphyrin carbenes (IPCs) are important reaction intermediates in engineered carbene transferase enzymes and homogeneous catalysis. However, discrepancies between theory and experiment complicate the understanding of IPC electronic structure. In the literature, this has been framed as whether the ground state is an open- vs closed-shell singlet (OSS vs CSS). Here we investigate the structurally dependent ground and excited spin-state energetics of a free carbene and its IPC analogs with variable trans axial ligands. In particular, for IPCs, multireference ab initio wave function methods are more consistent with experiment and predict a mixed singlet ground state that is dominated by the CSS (Fe(II) ← {:C(X)Y}0) configuration (i.e., electrophilic carbene) but that also has a small, non-negligible contribution from an Fe(III)-{C(X)Y}-• configuration (hole in d(xz), i.e., radical carbene). In the multireference approach, the "OSS-like" excited states are metal-to-ligand charge transfer (MLCT) in nature and are energetically well above the CSS-dominated ground state. The first, lowest energy of these "OSS-like" excited states is predicted to be heavily weighted toward the Fe(III)-{C(X)Y}-• (hole in d(yz)) configuration. As expected from exchange considerations, this state falls energetically above a triplet of the same configuration. Furthermore, potential energy surfaces (PESs) along the IPC Fe-C(carbene) bond elongation exhibit increasingly strong mixings between CSS/OSS characters, with the Fe(III)-{C(X)Y}-• configuration (hole in d(xz)) growing in weight in the ground state during bond elongation. The relative degree of electrophilic/radical carbene character along this structurally relevant PES can potentially play a role in reactivity and selectivity patterns in catalysis. Future studies on IPC reaction coordinates should evaluate contributions from ground and excited state multireference character.
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Affiliation(s)
- Gautam D Stroscio
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague 8, 18223 Czech Republic
| | - Ryan G Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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19
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Wang HX, Wan Q, Low KH, Zhou CY, Huang JS, Zhang JL, Che CM. Stable group 8 metal porphyrin mono- and bis(dialkylcarbene) complexes: synthesis, characterization, and catalytic activity. Chem Sci 2020; 11:2243-2259. [PMID: 32180931 PMCID: PMC7047983 DOI: 10.1039/c9sc05432d] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/30/2019] [Indexed: 12/17/2022] Open
Abstract
Alkyl-substituted carbene (CHR or CR2, R = alkyl) complexes have been extensively studied for alkylcarbene (CHR) ligands coordinated with high-valent early transition metal ions (a.k.a. Schrock carbenes or alkylidenes), yet dialkylcarbene (CR2) complexes remain less developed with bis(dialkylcarbene) species being little (if at all) explored. Herein, several group 8 metal porphyrin dialkylcarbene complexes, including Fe- and Ru-mono(dialkylcarbene) complexes [M(Por)(Ad)] (1a,b, M = Fe, Por = porphyrinato dianion, Ad = 2-adamantylidene; 2a,b, M = Ru) and Os-bis(dialkylcarbene) complexes [Os(Por)(Ad)2] (3a-c), are synthesized and crystallographically characterized. Detailed investigations into their electronic structures reveal that these complexes are formally low-valent M(ii)-carbene in nature. These complexes display remarkable thermal stability and chemical inertness, which are rationalized by a synergistic effect of strong metal-carbene covalency, hyperconjugation, and a rigid diamondoid carbene skeleton. Various spectroscopic techniques and DFT calculations suggest that the dialkylcarbene Ad ligand is unique compared to other common carbene ligands as it acts as both a potent σ-donor and π-acceptor; its unique electronic and structural features, together with the steric effect of the porphyrin macrocycle, make its Fe porphyrin complex 1a an active and robust catalyst for intermolecular diarylcarbene transfer reactions including cyclopropanation (up to 90% yield) and X-H (X = S, N, O, C) insertion (up to 99% yield) reactions.
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Affiliation(s)
- Hai-Xu Wang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Qingyun Wan
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Kam-Hung Low
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Cong-Ying Zhou
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
- College of Chemistry and Materials Science , Jinan University , Guangzhou , China
| | - Jie-Sheng Huang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Jun-Long Zhang
- Beijing National Laboratory for Molecular Sciences , College of Chemistry and Molecular Engineering , Peking University , Beijing , China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
- HKU Shenzhen Institute of Research & Innovation , Shenzhen , China
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20
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DeJesus JF, Jenkins DM. A Chiral Macrocyclic Tetra-N-Heterocyclic Carbene Yields an "All Carbene" Iron Alkylidene Complex. Chemistry 2020; 26:1429-1435. [PMID: 31788868 PMCID: PMC7024548 DOI: 10.1002/chem.201905360] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Indexed: 01/12/2023]
Abstract
The first chiral macrocyclic tetra-N-heterocyclic carbene (NHC) ligand has been synthesized. The macrocycle, prepared in high yield and large scale, was ligated onto palladium and iron to give divalent C2 -symmetric square planar complexes. Multinuclear NMR and single crystal X-ray diffraction demonstrated that there are two distinct NHCs on each ligand, due to the bridging chiral cyclohexane. Oxidation of the iron(II) complex with trimethylamine N-oxide yielded a bridging oxo complex. Diazodiphenylmethane reacted with the iron(II) complex at room temperature to give a paramagnetic diazoalkane complex; the same reaction yielded the "all carbene" complex at elevated temperature. Electrochemical measurements support the assignment of the "all carbene" complex being an alkylidene. Notably, the diazoalkane complex can be directly transformed into the alkylidene complex, which had not been previously demonstrated on iron. Finally, a test catalytic reaction with a diazoalkane on the iron(II) complex does not yield the expected cyclopropane, but actually the azine compound.
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Affiliation(s)
- Joseph F DeJesus
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - David M Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
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21
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Abstract
While the bottom-up design of enzymes appears to be an intractably complex problem, a minimal approach that combines elementary, de novo-designed proteins with intrinsically reactive cofactors offers a simple means to rapidly access sophisticated catalytic mechanisms. Not only is this method proven in the reproduction of powerful oxidative chemistry of the natural peroxidase enzymes, but we show here that it extends to the efficient, abiological—and often asymmetric—formation of strained cyclopropane rings, nitrogen–carbon and carbon–carbon bonds, and the ring expansion of a simple cyclic molecule to form a precursor for NAD+, a fundamentally important biological cofactor. That the enzyme also functions in vivo paves the way for its incorporation into engineered biosynthetic pathways within living organisms. By constructing an in vivo-assembled, catalytically proficient peroxidase, C45, we have recently demonstrated the catalytic potential of simple, de novo-designed heme proteins. Here, we show that C45’s enzymatic activity extends to the efficient and stereoselective intermolecular transfer of carbenes to olefins, heterocycles, aldehydes, and amines. Not only is this a report of carbene transferase activity in a completely de novo protein, but also of enzyme-catalyzed ring expansion of aromatic heterocycles via carbene transfer by any enzyme.
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22
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Manna D, Lo R, Hobza P. Spin modification of iron(ii) complexes via covalent (dative) and dispersion guided non-covalent bonding with N-heterocyclic carbenes: DFT, DLPNO-CCSD(T) and MCSCF studies. Dalton Trans 2020; 49:164-170. [DOI: 10.1039/c9dt04334a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin crossover from high spin Fe(ii)-phthalocyanine to low or intermediate spin via either dative covalent or non-covalent interaction by just varying the substituent using the same core ligand.
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Affiliation(s)
- Debashree Manna
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Rabindranath Lo
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Pavel Hobza
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
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23
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Damiano C, Sonzini P, Gallo E. Iron catalysts with N-ligands for carbene transfer of diazo reagents. Chem Soc Rev 2020; 49:4867-4905. [DOI: 10.1039/d0cs00221f] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review provides an overview of the catalytic activity of iron complexes of nitrogen ligands in driving carbene transfers towards CC, C–H and X–H bonds. The reactivity of diazo reagents is discussed as well as the proposed reaction mechanisms.
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Affiliation(s)
| | - Paolo Sonzini
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
| | - Emma Gallo
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
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24
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Liu Y, You T, Wang HX, Tang Z, Zhou CY, Che CM. Iron- and cobalt-catalyzed C(sp3)–H bond functionalization reactions and their application in organic synthesis. Chem Soc Rev 2020; 49:5310-5358. [DOI: 10.1039/d0cs00340a] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review highlights the developments in iron and cobalt catalyzed C(sp3)–H bond functionalization reactions with emphasis on their applications in organic synthesis, i.e. natural products and pharmaceuticals synthesis and/or modification.
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Affiliation(s)
- Yungen Liu
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
| | - Tingjie You
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Hai-Xu Wang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Zhou Tang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Cong-Ying Zhou
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Chi-Ming Che
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
- Department of Chemistry
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25
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Li F, Tang X, Xu Y, Wang C, Zhang L, Zhang J, Liu J, Li Z, Wang L. Hemoglobin-Catalyzed Synthesis of Indolizines Under Mild Conditions. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901591] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Fengxi Li
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Xuyong Tang
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Yaning Xu
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Chunyu Wang
- State Key Laboratory of Supramolecular Structure and Materials; Jilin University; 130023 Changchun P. R. China
| | - Liu Zhang
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Jiaxin Zhang
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Jiaxu Liu
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Zhengqiang Li
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
| | - Lei Wang
- Key Laboratory of Molecular Enzymology and Engineering of Ministry of Education School of Life Sciences; Jilin University; 130023 Changchun P. R. China
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26
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Zhang Y. Computational Investigations of Heme Carbenes and Heme Carbene Transfer Reactions. Chemistry 2019; 25:13231-13247. [DOI: 10.1002/chem.201901984] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/19/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Yong Zhang
- Department of Chemistry and Chemical Biology Stevens Institute of Technology 1 Castle Point on Hudson Hoboken NJ 07030 USA
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27
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Khade RL, Chandgude AL, Fasan R, Zhang Y. Mechanistic Investigation of Biocatalytic Heme Carbenoid Si-H Insertions. ChemCatChem 2019; 11:3101-3108. [PMID: 31428208 PMCID: PMC6699785 DOI: 10.1002/cctc.201801755] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Indexed: 12/28/2022]
Abstract
Recent studies reported the development of biocatalytic heme carbenoid Si-H insertions for the selective formation of carbon-silicon bonds, but many mechanistic questions remain unaddressed. To this end, a DFT mechanistic investigation was performed which reveals an FeII-based concerted hydride transfer mechanism with early transition state feature. The results from these computational analyses are consistent with experimental data of radical trapping, kinetic isotope effects, and structure-reactivity data using engineered variants of hemoproteins. Detailed geometric and electronic profiles along the heme catalyzed Si-H insertion pathways were provided to help understand the origin of experimental reactivity trends. Quantitative relationships between reaction barriers and some properties such as charge transfer from substrate to heme carbene and Si-H bond length change from reactant to transition state were found. Results suggest catalyst modifications to facilitate the charge transfer from the silane substrate to the carbene, which was determined to be a major electronic driving force of this reaction, should enable the development of improved biocatalysts for Si-H carbene insertion reactions.
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Affiliation(s)
- Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030 (USA)
| | - Ajay L Chandgude
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627 (USA)
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627 (USA)
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030 (USA)
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28
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Tinoco A, Wei Y, Bacik JP, Carminati DM, Moore EJ, Ando N, Zhang Y, Fasan R. Origin of high stereocontrol in olefin cyclopropanation catalyzed by an engineered carbene transferase. ACS Catal 2019; 9:1514-1524. [PMID: 31134138 DOI: 10.1021/acscatal.8b04073] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent advances in metalloprotein engineering have led to the development of a myoglobin-based catalyst, Mb(H64V,V68A), capable of promoting the cyclopropanation of vinylarenes with high efficiency and high diastereo- and enantioselectivity. Whereas many enzymes evolved in nature often exhibit catalytic proficiency and exquisite stereoselectivity, how these features are achieved for a non-natural reaction has remained unclear. In this work, the structural determinants responsible for chiral induction and high stereocontrol in Mb(H64V,V68A)-catalyzed cyclopropanation were investigated via a combination of crystallographic, computational (DFT), and structure-activity analyses. Our results show the importance of steric complementarity and non-covalent interactions involving first-sphere active site residues, heme-carbene, and the olefin substrate, in dictating the stereochemical outcome of the cyclopropanation reaction. High stereocontrol is achieved through two major mechanisms. First, by enforcing a specific conformation of the heme-bound carbene within the active site. Second, by controlling the geometry of attack of the olefin on the carbene via steric occlusion, attractive van der Waals forces and protein-mediated π-π interactions with the olefin substrate. These insights could be leveraged to expand the substrate scope of the myoglobin-based cyclopropanation catalyst toward non-activated olefins and to increase its cyclopropanation activity in the presence of a bulky α-diazo-ester. This work sheds first light into the origin of enzyme-catalyzed enantioselective cyclopropanation, furnishing a mechanistic framework for both understanding the reactivity of current systems and guiding the future development of biological catalysts for this class of synthetically important, abiotic transformations.
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Affiliation(s)
- Antonio Tinoco
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - John-Paul Bacik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniela M. Carminati
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Eric J. Moore
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Nozomi Ando
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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29
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Kielmann M, Senge MO. Molecular Engineering of Free-Base Porphyrins as Ligands-The N-H⋅⋅⋅X Binding Motif in Tetrapyrroles. Angew Chem Int Ed Engl 2019; 58:418-441. [PMID: 30067890 PMCID: PMC6391963 DOI: 10.1002/anie.201806281] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Indexed: 12/15/2022]
Abstract
The core N-H units of planar porphyrins are often inaccessible to forming hydrogen-bonding complexes with acceptor molecules. This is due to the fact that the amine moieties are "shielded" by the macrocyclic system, impeding the formation of intermolecular H-bonds. However, methods exist to modulate the tetrapyrrole conformations and to reshape the vector of N-H orientation outwards, thus increasing their availability and reactivity. Strategies include the use of porpho(di)methenes and phlorins (calixphyrins), as well as saddle-distorted porphyrins. The former form cavities due to interruption of the aromatic system. The latter are highly basic systems and capable of binding anions and neutral molecules via N-H⋅⋅⋅X-type H-bonds. This Review discusses the role of porphyrin(oid) ligands in various coordination-type complexes, means to access the core for hydrogen bonding, the concept of conformational control, and emerging applications, such as organocatalysis and sensors.
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Affiliation(s)
- Marc Kielmann
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity Biomedical Sciences InstituteTrinity College DublinThe University of Dublin152–160 Pearse StreetDublin 2Ireland
| | - Mathias O. Senge
- School of ChemistrySFI Tetrapyrrole LaboratoryTrinity Biomedical Sciences InstituteTrinity College DublinThe University of Dublin152–160 Pearse StreetDublin 2Ireland
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30
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Kravtsova AN, Guda LV, Polozhentsev OE, Pankin IA, Soldatov AV. Xanes Specroscopic Diagnostics of the 3D Local Atomic Structure of Nanostructured Materials. J STRUCT CHEM+ 2018. [DOI: 10.1134/s0022476618070259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Wang H, Schulz CE, Wei X, Li J. New Insights into the Ligand Nature of Carbene: Synthesis and Characterizations of Six-Coordinate Iron(II) Carbene Porphyrin Complexes. Inorg Chem 2018; 58:143-151. [PMID: 30565937 DOI: 10.1021/acs.inorgchem.8b02043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Charles E. Schulz
- Department of Physics, Knox College, Galesburg, Illinois 61401, United States
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32
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Herndon JW. The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2017. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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33
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Kielmann M, Senge MO. Molekulares Engineering freier Porphyrinbasen als Liganden - das N-H⋅⋅⋅X-Bindungsmotiv in Tetrapyrrolen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806281] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Marc Kielmann
- School of Chemistry; SFI Tetrapyrrole Laboratory; Trinity Biomedical Sciences Institute; Trinity College Dublin; The University of Dublin; 152-160 Pearse Street Dublin 2 Irland
| | - Mathias O. Senge
- School of Chemistry; SFI Tetrapyrrole Laboratory; Trinity Biomedical Sciences Institute; Trinity College Dublin; The University of Dublin; 152-160 Pearse Street Dublin 2 Irland
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34
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Torrent-Sucarrat M, Arrastia I, Arrieta A, Cossío FP. Stereoselectivity, Different Oxidation States, and Multiple Spin States in the Cyclopropanation of Olefins Catalyzed by Fe–Porphyrin Complexes. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01492] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Miquel Torrent-Sucarrat
- Department of Organic Chemistry I, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Centro de Innovación en Química Avanzada (ORFEO−CINQA), Manuel Lardizabal Ibilbidea 3, 20018 San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal Ibilbidea 4, 20018 San Sebastián/Donostia, Spain
- Ikerbasque, Basque Foundation for Science, Alameda Urquijo, 36-5 Plaza Bizkaia, 48011 Bilbao, Spain
| | - Iosune Arrastia
- Department of Organic Chemistry I, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Centro de Innovación en Química Avanzada (ORFEO−CINQA), Manuel Lardizabal Ibilbidea 3, 20018 San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal Ibilbidea 4, 20018 San Sebastián/Donostia, Spain
| | - Ana Arrieta
- Department of Organic Chemistry I, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Centro de Innovación en Química Avanzada (ORFEO−CINQA), Manuel Lardizabal Ibilbidea 3, 20018 San Sebastián/Donostia, Spain
| | - Fernando P. Cossío
- Department of Organic Chemistry I, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Centro de Innovación en Química Avanzada (ORFEO−CINQA), Manuel Lardizabal Ibilbidea 3, 20018 San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal Ibilbidea 4, 20018 San Sebastián/Donostia, Spain
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35
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Zhang RK, Huang X, Arnold FH. Selective CH bond functionalization with engineered heme proteins: new tools to generate complexity. Curr Opin Chem Biol 2018; 49:67-75. [PMID: 30343008 DOI: 10.1016/j.cbpa.2018.10.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 09/27/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022]
Abstract
CH functionalization is an attractive strategy to construct and diversify molecules. Heme proteins, predominantly cytochromes P450, are responsible for an array of CH oxidations in biology. Recent work has coupled concepts from synthetic chemistry, computation, and natural product biosynthesis to engineer heme protein systems to deliver products with tailored oxidation patterns. Heme protein catalysis has been shown to go well beyond these native reactions and now accesses new-to-nature CH transformations, including CN and CC bond forming processes. Emerging work with these systems moves us along the ambitious path of building complexity from the ubiquitous CH bond.
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Affiliation(s)
- Ruijie K Zhang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 210-41, Pasadena, CA 91125, United States
| | - Xiongyi Huang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 210-41, Pasadena, CA 91125, United States
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 210-41, Pasadena, CA 91125, United States.
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36
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Peng Q, Sage JT, Liu Y, Wang Z, Hu MY, Zhao J, Alp EE, Scheidt WR, Li J. How Does a Heme Carbene Differ from Diatomic Ligated (NO, CO, and CN -) Analogues in the Axial Bond? Inorg Chem 2018; 57:8788-8795. [PMID: 30010336 DOI: 10.1021/acs.inorgchem.8b00574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Compared to well studied diatomic ligands (NO, CN-, CO), the axial bonds of carbene hemes is much less known although its significance in biological chemistry. The unusually large quadrupole splitting (Δ EQ = +2.2 mm·s-1) and asymmetric parameter (η = 0.9) of the five-coordinate heme carbene [Fe(TTP)(CCl2)], which is the largest among all known low spin ferrohemes, has driven investigations by means of Mössbauer effect Nuclear Resonance Vibrational Spectroscopy (NRVS). Three distinct measurements on one single crystal (two in-plane and one out-of-plane) have demonstrated comprehensive vibrational structures including stretch (429) and bending modes (472 cm-1) of the axial Fe-CCl2, and revealed iron vibrational anisotropy in three orthogonal directions for the first time. Frontier orbital analysis especially comparisons with diatomic analogues (NO, CN-, CO) suggest that CCl2, similar to NO, has led to strong but anisotropic π bonding in a ligand-based "4C"-coordinate which induced the vibrational anisotropies and very large Mössbauer parameters. This is contrasted to CN- and CO complexes which possess a porphyrin-based "4N"-coordinate electronic and vibrational structures due to inherent on-axis linear ligation.
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Affiliation(s)
- Qian Peng
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - J Timothy Sage
- Department of Physics and Center for Interdisciplinary Research on Complex Systems , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Yulong Liu
- College of Materials Science and Optoelectronic Technology , University of Chinese Academy of Sciences , Yanqi Lake, Huairou, Beijing 101408 , China
| | - Zijian Wang
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Michael Y Hu
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jiyong Zhao
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - E Ercan Alp
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - W Robert Scheidt
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology , University of Chinese Academy of Sciences , Yanqi Lake, Huairou, Beijing 101408 , China
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37
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Capture and characterization of a reactive haem–carbenoid complex in an artificial metalloenzyme. Nat Catal 2018. [DOI: 10.1038/s41929-018-0105-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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38
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Lewis RD, Garcia-Borràs M, Chalkley MJ, Buller AR, Houk KN, Kan SBJ, Arnold FH. Catalytic iron-carbene intermediate revealed in a cytochrome c carbene transferase. Proc Natl Acad Sci U S A 2018; 115:7308-7313. [PMID: 29946033 PMCID: PMC6048479 DOI: 10.1073/pnas.1807027115] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently, heme proteins have been discovered and engineered by directed evolution to catalyze chemical transformations that are biochemically unprecedented. Many of these nonnatural enzyme-catalyzed reactions are assumed to proceed through a catalytic iron porphyrin carbene (IPC) intermediate, although this intermediate has never been observed in a protein. Using crystallographic, spectroscopic, and computational methods, we have captured and studied a catalytic IPC intermediate in the active site of an enzyme derived from thermostable Rhodothermus marinus (Rma) cytochrome c High-resolution crystal structures and computational methods reveal how directed evolution created an active site for carbene transfer in an electron transfer protein and how the laboratory-evolved enzyme achieves perfect carbene transfer stereoselectivity by holding the catalytic IPC in a single orientation. We also discovered that the IPC in Rma cytochrome c has a singlet ground electronic state and that the protein environment uses geometrical constraints and noncovalent interactions to influence different IPC electronic states. This information helps us to understand the impressive reactivity and selectivity of carbene transfer enzymes and offers insights that will guide and inspire future engineering efforts.
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Affiliation(s)
- Russell D Lewis
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Matthew J Chalkley
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Andrew R Buller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095;
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Frances H Arnold
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125;
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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39
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Postils V, Rodríguez M, Sabenya G, Conde A, Díaz-Requejo MM, Pérez PJ, Costas M, Solà M, Luis JM. Mechanism of the Selective Fe-Catalyzed Arene Carbon–Hydrogen Bond Functionalization. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03935] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Verònica Postils
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Mònica Rodríguez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Gerard Sabenya
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Ana Conde
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - M. Mar Díaz-Requejo
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
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40
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Wei Y, Tinoco A, Steck V, Fasan R, Zhang Y. Cyclopropanations via Heme Carbenes: Basic Mechanism and Effects of Carbene Substituent, Protein Axial Ligand, and Porphyrin Substitution. J Am Chem Soc 2018; 140:1649-1662. [PMID: 29268614 PMCID: PMC5875692 DOI: 10.1021/jacs.7b09171] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Catalytic carbene
transfer to olefins is a useful approach to synthesize
cyclopropanes, which are key structural motifs in many drugs and biologically
active natural products. While catalytic methods for olefin cyclopropanation
have largely relied on rare transition-metal-based catalysts, recent
studies have demonstrated the promise and synthetic value of iron-based
heme-containing proteins for promoting these reactions with excellent
catalytic activity and selectivity. Despite this progress, the mechanism
of iron-porphyrin and hemoprotein-catalyzed olefin cyclopropanation
has remained largely unknown. Using a combination of quantum chemical
calculations and experimental mechanistic analyses, the present study
shows for the first time that the increasingly useful C=C functionalizations
mediated by heme carbenes feature an FeII-based, nonradical,
concerted nonsynchronous mechanism, with early transition state character.
This mechanism differs from the FeIV-based, radical, stepwise
mechanism of heme-dependent monooxygenases. Furthermore, the effects
of the carbene substituent, metal coordinating axial ligand, and porphyrin
substituent on the reactivity of the heme carbenes was systematically
investigated, providing a basis for explaining experimental reactivity
results and defining strategies for future catalyst development. Our
results especially suggest the potential value of electron-deficient
porphyrin ligands for increasing the electrophilicity and thus the
reactivity of the heme carbene. Metal-free reactions were also studied
to reveal temperature and carbene substituent effects on catalytic
vs noncatalytic reactions. This study sheds new light into the mechanism
of iron-porphyrin and hemoprotein-catalyzed cyclopropanation reactions
and it is expected to facilitate future efforts toward sustainable
carbene transfer catalysis using these systems.
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Affiliation(s)
- Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology , 1 Castle Point on Hudson, Hoboken, New Jersey 07030, United States of America
| | - Antonio Tinoco
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Viktoria Steck
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Rudi Fasan
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology , 1 Castle Point on Hudson, Hoboken, New Jersey 07030, United States of America
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41
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Khade RL, Zhang Y. C-H Insertions by Iron Porphyrin Carbene: Basic Mechanism and Origin of Substrate Selectivity. Chemistry 2017; 23:17654-17658. [PMID: 29071754 DOI: 10.1002/chem.201704631] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Indexed: 11/09/2022]
Abstract
Recent experimental reports of heme carbene C-H insertions show promising results for sustainable chemistry due to good yield and selectivity, low cost of iron, and low/no toxicity of hemes. But mechanistic details are mostly unknown. Despite structural similarity and isoelectronic nature between heme carbene and the FeIV =O intermediate, our quantum chemical studies with detailed geometric and electronic information for the first time reveal an FeII -based, concerted, hydride-transfer mechanism, which is different from the FeIV -based stepwise hydrogen atom transfer mechanism for C-H functionalization by native heme enzymes. A trend of broad range experimental C-H insertion yields (0-88 %) of five different C-H bonds, including mostly non-functionalized moieties, was well reproduced. Results suggest that the substrate selectivity originates from the hydride formation capability. The predicted kinetic isotope effects were also in excellent agreement with experiment. Useful geometry, charge, and energy parameters well correlated with barriers were reported. These results provide the first theoretical evidence that carbene formation is the overall rate-limiting step, and suggest a key role of the formation of strong electrophilic heme carbene in developing heme-based C-H insertion catalysts and biocatalysts.
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Affiliation(s)
- Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030, USA
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030, USA
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42
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Das UK, Daifuku SL, Iannuzzi TE, Gorelsky SI, Korobkov I, Gabidullin B, Neidig ML, Baker RT. Iron(II) Complexes of a Hemilabile SNS Amido Ligand: Synthesis, Characterization, and Reactivity. Inorg Chem 2017; 56:13766-13776. [PMID: 29112382 DOI: 10.1021/acs.inorgchem.7b01802] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report an easily prepared bis(thioether) amine ligand, SMeNHSMe, along with the synthesis, characterization, and reactivity of the paramagnetic iron(II) bis(amido) complex, [Fe(κ3-SMeNSMe)2] (1). Binding of the two different thioethers to Fe generates both five- and six-membered rings with Fe-S bonds in the five-membered rings (av 2.54 Å) being significantly shorter than those in the six-membered rings (av 2.71 Å), suggesting hemilability of the latter thioethers. Consistent with this hypothesis, magnetic circular dichroism (MCD) and computational (TD-DFT) studies indicate that 1 in solution contains a five-coordinate component [Fe(κ3-SMeNSMe)(κ2-SMeNSMe)] (2). This ligand hemilability was demonstrated further by reactivity studies of 1 with 2,2'-bipyridine, 1,2-bis(dimethylphosphino)ethane, and 2,6-dimethylphenyl isonitrile to afford iron(II) complexes [L2Fe(κ2-SMeNSMe)2] (3-5). Addition of a Brønsted acid, HNTf2, to 1 produces the paramagnetic, iron(II) amine-amido cation, [Fe(κ3-SMeNSMe)(κ3-SMeNHSMe)](NTf2) (6; Tf = SO2CF3). Cation 6 readily undergoes amine ligand substitution by triphos, affording the 16e- complex [Fe(κ2-SMeNSMe)(κ3-triphos)](NTf2) (7; triphos = bis(2-diphenylphosphinoethyl)phenylphosphine). These complexes are characterized by elemental analysis; 1H NMR, Mössbauer, IR, and UV-vis spectroscopy; and single-crystal X-ray diffraction. Preliminary results of amine-borane dehydrogenation catalysis show complex 7 to be a selective and particularly robust precatalyst.
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Affiliation(s)
- Uttam K Das
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Stephanie L Daifuku
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Theresa E Iannuzzi
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Serge I Gorelsky
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Ilia Korobkov
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Bulat Gabidullin
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Michael L Neidig
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - R Tom Baker
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
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