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Lu H, Dzik WI, Xu X, Wojtas L, de Bruin B, Zhang XP. Experimental evidence for cobalt(III)-carbene radicals: key intermediates in cobalt(II)-based metalloradical cyclopropanation. J Am Chem Soc 2011; 133:8518-21. [PMID: 21563829 DOI: 10.1021/ja203434c] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New and conclusive evidence has been obtained for the existence of cobalt(III)-carbene radicals that have been previously proposed as the key intermediates in the underlying mechanism of metalloradical cyclopropanation by cobalt(II) complexes of porphyrins. In the absence of olefin substrates, reaction of [Co(TPP)] with ethyl styryldiazoacetate was found to generate the corresponding cobalt(III)-vinylcarbene radical that subsequently dimerizes via its γ-radical allylic resonance form to afford a dinuclear cobalt(III) porphyrin complex. X-ray structural analysis reveals a highly compact dimeric structure wherein the two metalloporphyrin units are arranged in a face-to-face fashion through a tetrasubstituted 1,5-hexadiene C(6)-bridge between the two Co(III) centers. The γ-radical allylic resonance form of the cobalt(III)-vinylcarbene radical intermediate could be effectively trapped by TEMPO via C-O bond formation to give a mononuclear cobalt(III) complex instead of the dimeric product. The allylic radical nature and related reactivity profile of the cobalt(III)-carbene radical, including its inability to abstract hydrogen atoms from toluene solvent, were established by DFT calculations.
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Affiliation(s)
- Hongjian Lu
- Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, USA
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Dzik WI, Zhang XP, de Bruin B. Redox noninnocence of carbene ligands: carbene radicals in (catalytic) C-C bond formation. Inorg Chem 2011; 50:9896-903. [PMID: 21520926 DOI: 10.1021/ic200043a] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this Forum contribution, we highlight the radical-type reactivities of one-electron-reduced Fischer-type carbenes. Carbene complexes of group 6 transition metals (Cr, Mo, and W) can be relatively easily reduced by an external reducing agent, leading to one-electron reduction of the carbene ligand moiety. This leads to the formation of "carbene-radical" ligands, showing typical radical-type reactivities. Fischer-type carbene ligands are thus clearly redox-active and can behave as so-called "redox noninnocent ligands". The "redox noninnocence" of Fischer-type carbene ligands is most clearly illustrated at group 9 transition metals in the oxidation state II+ (Co(II), Rh(II), and Ir(II)). In such carbene complexes, the metal effectively reduces the carbene ligand by one electron in an intramolecular redox process. As a result, the thus formed "carbene radicals" undergo a variety of radical-type C-C and C-H bond formations. The redox noninnocence of Fischer-type carbene ligands is not just a chemical curiosity but, in fact, plays an essential role in catalytic cyclopropanation reactions by cobalt(II) porphyrins. This has led to the successful development of new chiral cobalt(II) porphyrins as highly effective catalysts for asymmetric cyclopropanation with unprecedented reactivity and stereocontrol. The redox noninnocence of the carbene intermediates results in the formation of carbene-radical ligands with nucleophilic character, which explains their effectiveness in the cyclopropanation of electron-deficient olefins and their reduced tendency to mediate carbene dimerization. To the best of our knowledge, this represents the first example in which the redox noninnocence of a reacting ligand plays a key role in a catalytic organometallic reaction. This Forum contribution ends with an outlook on further potential applications of one-electron-activated Fischer-type carbenes in new catalytic reactions.
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Affiliation(s)
- Wojciech I Dzik
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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Sierra MA, Gómez-Gallego M, Martínez-Alvarez R. Fischer Carbene Complexes: Beautiful Playgrounds To Study Single Electron Transfer (SET) Reactions. Chemistry 2007; 13:736-44. [PMID: 17171739 DOI: 10.1002/chem.200601470] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The knowledge of the reactivity of Fischer carbene complexes in electron transfer processes is still in the early stage of development, but interesting advances are foreseeable in this young branch of metal-carbene chemistry. Although these compounds have a dual reactivity (which makes them good substrates for oxidation and reduction processes), their behavior towards chemical electron transfer (ET) reagents was unknown until very recently. This article covers the progress accomplished in the reactivity of these compounds towards chemical ET reagents (C(8)K or SmI(2)), as well as the use of nonconventional sources of electrons, such as electrospray ionization (ESI) to induce ET processes. Special emphasis will be made on the effect of the structure of the starting carbene in the outcome of the reaction and in discussing the different mechanisms proposed.
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Affiliation(s)
- Miguel A Sierra
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
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Zheng Z, Yu Z, Wang L, He W, Liu Z, Xiuwen Han. Biscarbene complexes from the reactions of O-ethyl lactim and 1-alkynyl Fischer carbene complexes of chromium and tungsten. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2006.08.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fehn A, Briel O, Beck W. Hydrocarbon‐Bridged Complexes, XL. Polyene‐Bridged Iridium(III), Palladium(II), and Platinum(II) Complexes of Schiff Bases from α,ω‐Polyene Dialdehydes and α‐Amino Acids or
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‐Aminophenol. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/cber.19971301018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Armin Fehn
- Institut fär Anorganische Chemie der Ludwig‐Maximilians‐Universität, Meiserstraße 1, D‐80333 München, Germany
| | - Oliver Briel
- Institut fär Anorganische Chemie der Ludwig‐Maximilians‐Universität, Meiserstraße 1, D‐80333 München, Germany
| | - Wolfgang Beck
- Institut fär Anorganische Chemie der Ludwig‐Maximilians‐Universität, Meiserstraße 1, D‐80333 München, Germany
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Chen J, Yu Z, Zheng Z, Gu K, Wu S, Zeng F, Tan W, Wu X, Xiao W. Chemoselective Stepwise Demetalation of Unusually Stable Fischer Biscarbene Complexes by Domino [4+2]/[2+2] Cycloaddition of 2-Isopropenyl-2-oxazoline to 1-Alkynyl Fischer Carbene Complexes of Chromium and Tungsten. Organometallics 2004. [DOI: 10.1021/om049213d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jinzhu Chen
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Zhengkun Yu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Zhaoyan Zheng
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Kaichun Gu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Sizhong Wu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Fanlong Zeng
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Weiqiang Tan
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xiaowei Wu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Wenjing Xiao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China, and College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
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High diastereoselective Michael and aldol additions of Fischer-type alkyl(hydrazino)carbene complexes: synthesis of new hydrazides. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(03)00523-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fernández I, Sierra MA, Mancheño MJ, Gómez-Gallego M, Ricart S. Synthesis of Cyclophanic Chromium(0) Bis(carbene) Complexes. Organometallics 2001. [DOI: 10.1021/om010561e] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Israel Fernández
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain, and Departament de Materials Moleculars, Institut de Ciencies de Materials de Barcelona, CSIC (ICMAB), Campus de la UAB, 08193-Bellaterra, Spain
| | - Miguel A. Sierra
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain, and Departament de Materials Moleculars, Institut de Ciencies de Materials de Barcelona, CSIC (ICMAB), Campus de la UAB, 08193-Bellaterra, Spain
| | - María José Mancheño
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain, and Departament de Materials Moleculars, Institut de Ciencies de Materials de Barcelona, CSIC (ICMAB), Campus de la UAB, 08193-Bellaterra, Spain
| | - Mar Gómez-Gallego
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain, and Departament de Materials Moleculars, Institut de Ciencies de Materials de Barcelona, CSIC (ICMAB), Campus de la UAB, 08193-Bellaterra, Spain
| | - Susagna Ricart
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain, and Departament de Materials Moleculars, Institut de Ciencies de Materials de Barcelona, CSIC (ICMAB), Campus de la UAB, 08193-Bellaterra, Spain
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Ulrich K, Guerchais V, Dötz KH, Toupet L, Le Bozec H. Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(200103)2001:3<725::aid-ejic725>3.0.co;2-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Synthesis and reactivity of μ-bis(carbene)dimanganese complexes. X-ray structures of {Cp′(CO)2Mn}2{μ-C(OEt)CH2CH2(EtO)C}, (E)-{Cp′(CO)2Mn}2{μ-C(OEt)CHCH(EtO)C} and {Cp′(CO)2Mn}2{μ-H}. J Organomet Chem 2001. [DOI: 10.1016/s0022-328x(00)00719-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sierra MA. Di- and polymetallic heteroatom stabilized (Fischer) metal carbene complexes. Chem Rev 2000; 100:3591-638. [PMID: 11749323 DOI: 10.1021/cr9804137] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M A Sierra
- Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain
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Hartbaum C, Mauz E, Roth G, Weissenbach K, Fischer H. Bimetallic Complexes with Conjugated C4, C6, C10, and C14 Bridges: Synthetic Routes to Alkynediyl-Bridged Bis(carbene) Complexes. Organometallics 1999. [DOI: 10.1021/om990145i] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cornelia Hartbaum
- Fakultät für Chemie, Universität Konstanz, Fach M727, D-78457 Konstanz, Germany
| | - Elvira Mauz
- Fakultät für Chemie, Universität Konstanz, Fach M727, D-78457 Konstanz, Germany
| | - Gerhard Roth
- Fakultät für Chemie, Universität Konstanz, Fach M727, D-78457 Konstanz, Germany
| | - Kerstin Weissenbach
- Fakultät für Chemie, Universität Konstanz, Fach M727, D-78457 Konstanz, Germany
| | - Helmut Fischer
- Fakultät für Chemie, Universität Konstanz, Fach M727, D-78457 Konstanz, Germany
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Terblans YM, Marita Roos H, Lotz S. Synthesis, characterization and decomposition patterns for thienylene bridged dinuclear biscarbene complexes of manganese and chromium in refluxing carbon disulphide and acetone. J Organomet Chem 1998. [DOI: 10.1016/s0022-328x(98)00730-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hartbaum C, Roth G, Fischer H. Polynuclear Complexes with Propynylidene C3-Bridges: General Synthetic Route to Bis-, Tris-, and Tetrakis(ethynylcarbene) Complexes. Eur J Inorg Chem 1998. [DOI: 10.1002/(sici)1099-0682(199802)1998:2<191::aid-ejic191>3.0.co;2-t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kohlenwasserstoffverbrückte metallkomplexe XXXVIII. Verbrückte bis(carben)-komplexe (OC)5MC(OMe)C(H)CH2C(OMe)M(CO)5(MCr, W) aus anionischen carbenkomplexen vom fischer-typ und fumarsäuredichlorid. J Organomet Chem 1997. [DOI: 10.1016/s0022-328x(96)06918-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Péron V, Porhiel E, Ferrand V, Le Bozec H. Synthesis of mixed bis(alkenylcarbene) ditungsten complexes by sequential activation of dialkynols. J Organomet Chem 1997. [DOI: 10.1016/s0022-328x(97)00077-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hydrocarbon bridged metal complexes. XXXIV. Synthesis, structure and attempted decarbonylation of a trans 11,12-bis(dicarbonylcyclopentadienylironacyl) substituted dihydro 9,10-ethanoanthracene. J Organomet Chem 1996. [DOI: 10.1016/0022-328x(95)06064-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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