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RESEARCH FRONT
Contents Vol 64(8)

Abnormal N-heterocyclic Carbenes: More than Just Exceptionally Strong Donor Ligands

Anneke Krüger A and Martin Albrecht A B
+ Author Affiliations
- Author Affiliations

A School of Chemistry & Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.

B Corresponding author. Email: martin.albrecht@ucd.ie

Australian Journal of Chemistry 64(8) 1113-1117 https://doi.org/10.1071/CH11265
Submitted: 8 July 2011  Accepted: 18 July 2011   Published: 19 August 2011

Abstract

Complexes comprising a so-called abnormal carbene ligand, which displays pronounced mesoionic character, have recently been shown to be competent catalyst precursors for bond activation processes and oxidative transformations, including base-free alcohol oxidation and water oxidation. In this highlight we propose that these abnormal carbene ligands are not just useful spectator ligands but also actively participate in the bond activation step. This mode of action is partially based on the exceptionally strong donor properties of the ligand and, specifically, on the mesoionic character of these abnormal carbenes. The mesoionic properties provide a reservoir for charges and holes and thus induce efficient ligand-metal cooperativity, which is beneficial in particular for oxidation catalysis that involves concerted proton and electron transfer processes.


References

[1]  A. J. Arduengo, R. L. Harlow, M. Kline, J. Am. Chem. Soc. 1991, 113, 361.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXmt1Sjuw%3D%3D&md5=36602e5ce523fcf25d5682db3592699dCAS |

[2]  (a) W. A. Herrmann, Angew. Chem. Int. Ed. 2002, 41, 1290.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xjt1ertbY%3D&md5=d6b7d5580c2168f96a56e9139375db6cCAS |
      (b) F. E. Hahn, M. C. Jahnke, Angew. Chem. Int. Ed. 2008, 47, 3122.
         | Crossref | GoogleScholarGoogle Scholar |
      (c) S. Diez-González, N. Marion, S. P. Nolan, Chem. Rev. 2009, 109, 3612.
         | Crossref | GoogleScholarGoogle Scholar |

[3]  (a) N. M. Scott, H. Clavier, P. Jahjoor, E. D. Stevens, S. P. Nolan, Organometallics 2008, 27, 3181.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXmslamuro%3D&md5=0ba9705609965f67a55e7af0c337e5f9CAS |
      (b) V. Lavallo, R. H. Grubbs, Science 2009, 326, 559.
         | Crossref | GoogleScholarGoogle Scholar |

[4]  (a) M. Poyatos, J. A. Mata, E. Peris, Chem. Rev. 2009, 109, 3677.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXit1ektbY%3D&md5=6e96f9ea6b84e0d4eccb61eb0dbce681CAS |
      (b) M. Heckenroth, A. Neels, H. Stoeckli-Evans, M. Albrecht, Inorg. Chim. Acta 2006, 359, 1929.
         | Crossref | GoogleScholarGoogle Scholar |

[5]  (a) P. L. Arnold, J. Pearson, Coord. Chem. Rev. 2007, 251, 596.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhsFOjsrc%3D&md5=3be396f77ba41902ecb2a56295ab6b32CAS |
      (b) M. Albrecht, Chem. Commun. (Camb.) 2008, 3601.
         | Crossref | GoogleScholarGoogle Scholar |
      (c) O. Schuster, L. Yang, H. G. Raubenheimer, M. Albrecht, Chem. Rev. 2009, 109, 3445.
         | Crossref | GoogleScholarGoogle Scholar |

[6]  Recently, Bertrand and coworkers suggested [6b] to term these ligands mesoionic carbenes [6c]. We agree that this terminology describes the bonding situation more appropriately, though it should be noted that also the normal 2-imidazolylidene-type carbenes and presumably most classic Fischer-type carbene ligands possess a substantial mesoionic character (cf the generally adopted resonance representation including a metal-ligand single bond). Obviously, the mesoionic contribution in normal NHCs is generally smaller than in abnormal homologues, yet it may be difficult to draw a clear line of separation.
      (b) G. Guisado-Barrios, J. Bouffard, B. Donnadieu, G. Bertrand, Angew. Chem. Int. Ed. 2010, 49, 4759.
      IUPAC Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML.

[7]  (a) V. Lavallo, C. A. Dyker, B. Donnadieu, G. Bertrand, Angew. Chem. Int. Ed. 2008, 47, 5411.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXovFynsLo%3D&md5=a2db232e2d2cb5f01233c073782ef9ffCAS |
      (b) E. Aldeco-Perez, A. J. Rosenthal, B. Donnadieu, P. Parameswaran, G. Frenking, G. Bertrand, Science 2009, 326, 556.
         | Crossref | GoogleScholarGoogle Scholar |

[8]  A. M. Magill, K. J. Cavell, B. F. Yates, J. Am. Chem. Soc. 2004, 126, 8717.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXlsF2msbw%3D&md5=ce5462d2de15648e8d9547b15fd56810CAS |

[9]  R. Tonner, G. Heydenrych, G. Frenking, Chem. Asian J. 2007, 2, 1555.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhsVGlsLzF&md5=375eb91befa4bd4503059e21cdf15c68CAS |

[10]  A. R. Chianese, A. Kovacevic, B. M. Zeglis, J. W. Faller, R. H. Crabtree, Organometallics 2004, 23, 2461.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjtVCju7s%3D&md5=d3829979748f30d2f45fe1130e4242dfCAS |

[11]  M. Heckenroth, E. Kluser, A. Neels, M. Albrecht, Angew. Chem. Int. Ed. 2007, 46, 6293.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXpvVSmtL0%3D&md5=16b9eee42dade96679d2d41ae1a2b11dCAS |

[12]  M. Heckenroth, A. Neels, M. G. Garnier, P. Aebi, A. W. Ehlers, M. Albrecht, Chemistry 2009, 15, 9375.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhtFGlu7bK&md5=b7959969062fa3a180505721495f8224CAS |

[13]  (a) H. G. Raubenheimer, S. Cronje, Dalton Trans. 2008, 1265.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXisVKjt7c%3D&md5=2865bcaed87a2982e69da5ae0aa216f3CAS |
      (b) P. Mathew, A. Neels, M. Albrecht, J. Am. Chem. Soc. 2008, 130, 13534.
         | Crossref | GoogleScholarGoogle Scholar |
      (c) M. Iglesias, M. Albrecht, Dalton Trans. 2010, 39, 5213.
         | Crossref | GoogleScholarGoogle Scholar |
      (d) Y. Han, H. V. Huynh, Dalton Trans. 2011, 40, 2141.
         | Crossref | GoogleScholarGoogle Scholar |

[14]  A. Krüger, M. Albrecht, in N-heterocyclic carbenes: From Laboratory Curiosities to Efficient Synthetic Tools, ed. Silvia Diez-Gonzalez (Ed.), RSC (Cambridge, UK) 2011, p. 134.

[15]  (a) L. Yang, A. Krüger, A. Neels, M. Albrecht, Organometallics 2008, 27, 3161.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXmtlWmsro%3D&md5=03692f166c7f0e0dc75aa09b1af2ea5eCAS |
      (b) A. Prades, E. Peris, M. Albrecht, Organometallics 2011, 30, 1162.
         | Crossref | GoogleScholarGoogle Scholar |

[16]  A. Krüger, A. Neels, M. Albrecht, Chem. Commun. (Camb.) 2010, 46, 315.
         | Crossref | GoogleScholarGoogle Scholar |

[17]  A. Krüger, L. J. L. Häller, H. Müller-Bunz, O. Serada, A. Neels, S. A. Macgregor, M. Albrecht, Dalton Trans. 2011, 40,
         | Crossref | GoogleScholarGoogle Scholar |

[18]  M. K. Denk, J. M. Rodezno, J. Organomet. Chem. 2000, 608, 122.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXnslWlsr0%3D&md5=81b1d4b6d4ddc9f824e041a09ce4d4e8CAS |

[19]  L. Mercs, A. Neels, M. Albrecht, Dalton Trans. 2008, 5570.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXht1CqtrrJ&md5=c483dac39c406ea147de217cd52913a7CAS |

[20]     (a) This concept is better known for negative charge compensation, especially by intramolecular immobilization of a borate anion as in tris(pyrazolyl)borate and related tris(phosphino)borates: (a) S. Trofimenko, J. Am. Chem. Soc. 1966, 88, 1842. 10.1021/JA00960A065
      (b) J. C. Thomas, J. C. Peters, J. Am. Chem. Soc. 2001, 123, 5100.
         | Crossref | GoogleScholarGoogle Scholar |

[21]  Krüger  A.Albrecht  M.manuscript submitted.

[22]  R. N. Perutz, S. Sabo-Etienne, Angew. Chem. Int. Ed. 2007, 46, 2578.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXksVWrtrg%3D&md5=2a8f8f2531922b4983eec55b417cd85dCAS |

[23]  (a) D. B. Grotjahn, Chemistry 2005, 11, 7146.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtlequ7rP&md5=d8820a6468b32925fc6918f4703cceecCAS |
      (b) H. Grützmacher, Angew. Chem. Int. Ed. 2008, 47, 1814.
         | Crossref | GoogleScholarGoogle Scholar |
      (c) R. Noyori, T. Ohkuma, Angew. Chem. Int. Ed. 2001, 40, 40.
         | Crossref | GoogleScholarGoogle Scholar |
      (d) M. Lafrance, K. Fagnou, J. Am. Chem. Soc. 2006, 128, 16496.
         | Crossref | GoogleScholarGoogle Scholar |
      (e) D. L. Davies, S. M. A. Donald, O. Al-Duaij, S. A. Macgregor, M. Pölleth, J. Am. Chem. Soc. 2006, 128, 4210.
         | Crossref | GoogleScholarGoogle Scholar |
      (f) C. Gunanathan, Y. Ben-David, D. Milstein, Science 2007, 317, 790.
         | Crossref | GoogleScholarGoogle Scholar |
      (g) T. Zweifel, J.-V. Naubron, H. Grützmacher, Angew. Chem. Int. Ed. 2009, 48, 559.
         | Crossref | GoogleScholarGoogle Scholar |

[24]  M. Heckenroth, V. Khlebnikov, A. Neels, P. Schurtenberger, M. Albrecht, ChemCatChem 2011, 3, 167.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXit1yiug%3D%3D&md5=7171e97be6e3e91209b3e8082403a93dCAS |

[25]  W. A. Herrmann, J. Schütz, G. D. Frey, E. Herdtweck, Organometallics 2006, 25, 2437.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xjt1KmtL8%3D&md5=e9ccaef81df940674608014b4b8d9afdCAS |

[26]     (a) While in abnormal carbene complexes, a 1,3-addition may be prevalent, normal carbenes are more likely to undergo a (less favored) 1,2-addition (including the metal-bound carbon; a model product may be the compound resulting from NH3 activation, see): (a) Frey  G. D.Lavallo  V.Donnadieu  B.Schoeller  W. W.Bertrand  G. Science 2007, 316, 439. 10.1126/SCIENCE.1141474
      (b) P. M. Zimmerman, A. Paul, C. B. Musgrave, Inorg. Chem. 2009, 48, 5418.
         | Crossref | GoogleScholarGoogle Scholar |

[27]  (a) N. D. McDaniel, F. J. Coughlin, L. L. Tinker, S. Bernhard, J. Am. Chem. Soc. 2008, 130, 210.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtl2itLjI&md5=ae7f385889a1b222579e84e9c085247cCAS |
      (b) J. F. Hull, D. Balcells, J. D. Blakemore, C. D. Incarvito, O. Eisenstein, G. W. Brudvig, R. H. Crabtree, J. Am. Chem. Soc. 2009, 131, 8731.
      (c) X. Sala, I. Romero, M. Rodriguez, L. Escriche, A. Llobet, Angew. Chem. Int. Ed. 2009, 48, 2842.
         | Crossref | GoogleScholarGoogle Scholar |

[28]  (a) R. Lalrempuia, N. D. McDaniel, H. Müller-Bunz, S. Bernhard, M. Albrecht, Angew. Chem. Int. Ed. 2010, 49, 9765.
         | Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhsFaqsL%2FK&md5=fffb4d8efedfc619508b093048d26232CAS |
      (b) L. Bernet, R. Lalrempuia, W. Ghattas, H. Mueller-Bunz, L. Vigara, A. Llobet, M. Albrecht, Chem. Commun. (Camb.) 2011, 47, 8058.
         | Crossref | GoogleScholarGoogle Scholar |