Abstract
Unlike N-heterocyclic carbenes (NHCs), which are now used ubiquitously in metal-based chemistry, the nitrogen-derived analogue (in which a carbon is replaced with the isoelectronic nitrogen cation, a nitrenium ion) has remained elusive as a ligand for metals. This is especially intriguing, because several other main-group analogues of NHCs have been prepared, and have been shown to coordinate with transition-metal complexes. Here, we describe the preparation of several N-heterocyclic nitrenium ions that are isoelectronic and isostructural to NHCs, and study their ligand properties. The formation of relatively strong nitrenium–metal bonds is unambiguously confirmed, in solution by selective 15N-labelling experiments, and in the solid state by X-ray crystallography. Experimental and computational studies of the electronic properties of this novel type of ligand suggest that they are poor σ-donors and good π-acceptors.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Harlow, R. L., Kline, M. & Arduengo J. A. A stable crystalline carbene. J. Am. Chem. Soc. 113, 361–363 (1991).
Enders, D., Niemeier, O. & Henseler, A. Organocatalysis by N-heterocyclic carbenes. Chem. Rev. 107, 5606–5655 (2007).
Glorius, F. (ed.) N-heterocyclic Carbenes in Transition Metal Catalysis (Springer, 2006).
Aldeco-Perez, E., Rosenthal, A. J., Donnadieu, B., Parameswaran, P., Gernot, F. & Bertrand, G. Isolation of a C5-deprotonated imidazolium, a crystalline ‘abnormal’ N-heterocyclic carbene. Science 326, 556–559 (2009).
Melami, M, Soleilhavoup, M. & Bertrand, G. Stable cyclic carbenes and related species beyond diaminocarbenes. Angew. Chem. Int. Ed. 49, 8810–8849 (2010).
Schuster, O., Yang, L., Raubenheimer, H. G. & Albrecht, M. Beyond conventional N-heterocyclic carbenes: abnormal, remote, and other classes of NHC ligands with reduced heteroatom stabilization. Chem. Rev. 109, 3445–3478 (2009).
Sole, S., Gornitzka, H., Schoeller, W. W., Bourissou, D. & Bertrand, G. (Amino)(aryl)carbenes: stable singlet carbenes featuring a spectator substituent. Science 292, 1901–1903 (2001).
Vignolle, J., Cattoen, X., & Bourissou, D. Stable noncyclic singlet carbenes. Chem. Rev. 109, 3333–3384 (2009).
Krahulic, K. E., Enright, G. D., Parvez, M. & Roesler, R. A stable N-heterocyclic carbene with a diboron backbone. J. Am. Chem. Soc. 127, 4142–4143 (2005).
Prasang, C., Donnadieu, B. & Bertrand, G. Stable planar six-6π-electron six-membered N-heterocyclic carbenes with tunable electronic properties. J. Am. Chem. Soc. 127, 10182–10183 (2005).
Denk, M. et al. Synthesis and structure of a stable silylene. J. Am. Chem. Soc. 116, 2691–2692 (1994).
Yoo, H., Carroll, P. J. & Berry, D. H. Synthesis and structure of ruthenium–silylene complexes: activation of Si–Cl bonds in N-heterocyclic silanes. J. Am. Chem. Soc. 128, 6038–6039 (2006).
Herrmann, W. A. et al. Stable cyclic germilendiyls (‘cyclogermilenes’): synthesis, structure, metal complexes and thermolyses. Angew. Chem. Int. Ed. 31, 1485–1488 (1992).
Segawa, Y., Yamashita, M. & Nozaki, K. Boryllithium: isolation, characterization, and reactivity as boryl anion. Science 314, 113–115 (2006).
Segawa, Y., Yamashita, M. & Nozaki, K. Syntheses of PBP pincer iridium complexes: a supporting boryl ligand. J. Am. Chem. Soc. 131, 9201–9203 (2009).
Schmidt, E. S., Jockisch, A. & Schmidbaur, H. A carbene analogue with low-valent gallium as a heteroatom in a quasi-aromatic imidazolate anion. J. Am. Chem. Soc. 121, 9758–9759 (1999).
Baker, R. J., Cameron, J. & Platts, J. A. Analogies between the reactivities of an anionic gallium(I) heterocycle and N-heterocyclic carbenes toward metallocenes. J. Am. Chem. Soc. 125, 10534–10535 (2003).
Denk, M. K., Gupta, S. & Ramachandran, R. Aromatic phosphenium cations. Tetrahedron. Lett. 37, 9025–9028 (1996).
Caputo, C. A. et al. A cation-captured palladium(0) anion: synthesis, structure, and bonding of [PdBr(PPh3)2]− ligated by an N-heterocyclic phosphenium cation. Organometallics 28, 5261–5265 (2009).
Carmalt, C. J., Lomeli, V., McBurnett, B. G. & Cowley, A. H. Cyclic phosphenium and arsenium cations with 6π electrons and related systems. Chem. Commun., 2095–2096 (1997).
Burck, S. et al. N-heterocyclic phosphenium, arsenium and stibenium ions as ligands in transition metal complexes: a comparative experimental and computational study. Z. Anorg. Allg. Chem. 631, 1403–1412 (2005).
Boche, G. et al. Crystal and electronic structure of stable nitrenium ions. A comparison with structurally related carbenes. J. Am. Chem. Soc. 118, 4925–4930 (1996).
McIlroy, S., Cramer, C. J. & Falvey, D. E. Singlet–triplet energy gaps in highly stabilized nitrenium ions: experimental and theoretical study of 1,3-dimethylbenzotriazolium ion. Org. Lett. 2, 2451–2454 (2000).
Hassani, K., Marsch, M., Harms, K. & Boche, G. Crystal structure of 2-(1,3-dimethylbenzotriazolium) nickeltetrabromide, (C8H10N3)NiBr4 . Z. Kristallogr. NCS 216, 425–426 (2001).
Goreshnik, E. A., Pavlyuk, A. V., Schollmeyer, D. & Mys'kiv, M. G. Copper(I) π-complex with 1,3-diallylbenzotriazolium [C6H4N3(C3H5)2]Cu2Br3: synthesis and crystal structure. Rus. J. Coord. Chem. 25, 653–657 (1999).
Wu, T., Li, D. & Huang, X.-C. Anionic CunIn cluster-based architectures induced by in situ generated N-alkylated cationic triazolium salts. Cryst. Growth Design 8, 568–574 (2008).
Morales-Morales, D. & Jensen, C. (eds) The Chemistry of Pincer Compounds (Elsevier, 2007).
van Koten, G. & Albrecht, M. Platinum group organometallics based on ‘pincer’ complexes: sensors, switches, and catalysts. Angew. Chem. Int. Ed. 40, 3750–3781 (2001).
van der Boom, M. E. & Milstein, D. Cyclometalated phosphine-based pincer complexes: mechanistic insight in catalysis, coordination, and bond activation. Chem. Rev. 103, 1759–1792 (2003).
Carlton, L. & de Sousa, G. A 15N-NMR spectroscopy study of some rhodium complexes of 3,5-dicarbomethoxy-4-phenylpyridine-15N. Polyhedron 12, 1377–1382 (1993).
Meji, R., Stufkens, D. J. & Vrieze, K. Cumulated double bond systems as ligands. J. Organomet. Chem. 164, 353–370 (1979).
Nifatyev, E. E. et al. Complexation of rhodium(I) with 5-hydro-3,8-R,R-1,6-dioxa-4,9-diaza-5-phosphaspiro[4.4]nonane. J. Organomet. Chem. 397, 245–253 (1990).
Donovan-Mtunzi, S. & Richards, R. L. Spectroscopy of terminal dinitrogen complexes: nitrogen-15 and phosphorus-31 nuclear magnetic resonance. J. Chem. Soc. Dalton Trans. 469–474 (1984).
Gaviglio, C., Ben-David, Y., Shimon, L. J. W., Doctorovich, F. & Milstein, D. Synthesis, structure, and reactivity of nitrosyl pincer-type rhodium complexes. Organometallics 28, 1917–1926 (2009).
Bose, K. S. & Abbot, E. H. Natural abundance nitrogen-15 nuclear magnetic resonance spectroscopy of some rhodium(III) complexes. Inorg. Chem. 16, 3190–3193 (1977).
Arduengo, A. J. Looking for stable carbene: the difficulty in starting anew. Acc. Chem. Res. 32, 913–921 (1999).
Tuononen, H. M., Roesler, R., Dutton, J. L. & Ragogna, P. J. Electronic structures of main-group carbene analogues. Inorg. Chem. 46, 10693–10706 (2007).
Spinney, H. A., Yap, G. P. A., Korobkov, I., DiLabio, G. & Richeson, D. S. Construction of a stable N-heterocyclic phosphenium cation with an electron-rich framework and its complexation to rhodium. Organometallics 25, 3541–3543 (2006).
Abrams, M. B., Scott, B. L. & Baker, R. T. Sterically tunable phosphenium cations: synthesis and characterization of bis(arylamino)phosphenium ions, phosphinophosphenium adducts, and the first well-defined rhodium phosphenium complexes. Organometallics 19, 4944–4956 (2000).
Hahn, C., Sieler, J. & Taube, R. Synthesis of 2,6-bis(diphenylphosphinomethyl)pyridine-monoligand-rhodium(I) complexes [Rh(PNP)L]X with L = pyridine, CH3CN, DMSO and X = CF3SO3, BF4 from the corresponding ethylene complex and comparison of the structures to the piperidine complex (L = piperidine, X = BF4). Polyhedron 17, 1183–1193 (1998).
Rangappa, K. S. et al. Synthesis and crystal structure of 1,3-dimethyl benzotriazolium trifluoromethane sulfonate. Mol. Cryst. Liq. Cryst. 357, 291–298 (2001).
Schmidt, A. et al. N-heterocyclic carbenes of 5-haloindazoles generated by decarboxylation of 5-haloindazolium-3-carboxylates. Eur. J. Org. Chem. 29, 4909–4916 (2007).
Hutchins, L. D., Duesler, E. N. & Paine, R. T. Structure and bonding in a phosphenlum ion–iron complex. A demonstratlon of phosphenium ion acceptor properties. Organometallics 1, 1254–1256 (1982).
Boche, G., Willeke, C., Marsch, M. & Harms, K. Crystal structure of 1,3-dibenzyl-1,2,3-triazolium iodide, (C6H5CH2)2(C2H2N3)+I−. Z. Kristall. 211, 583–584 (1996).
Zeng, J. Y., Hsieh, M.-H. & Lee, H. M. Rhodium complexes of PCNHCP: oxidative addition of dichloromethane and catalytic hydrosilylation of alkynes affording (E)-alkenylsilanes. J. Organomet. Chem. 690, 5662–5671 (2005).
Vasapollo, G., Giannoccaro, P., Nobile, C. F. & Sacco, A. Synthesis and reactivity towards gas molecules of chloro-2,6-di(diphenylphosphinomethyl)pyridine rhodium(I). Inorg. Chim. Acta 48, 125–128 (1981).
Burford, N. & Ragogna, P. J. New synthetic opportunities using Lewis acidic phosphines. J. Chem. Soc. Dalton Trans. 4307–4315 (2002).
Dapprich, S. & Frenking, G. Investigation of donor–acceptor interactions: a charge decomposition analysis using fragment molecular orbitals. J. Phys. Chem. 99, 9352–9362 (1995).
Acknowledgements
The authors acknowledge financial support from the US–Israel Binational Science Foundation (grant no. 2008391), the Israel Science Foundation (grant no. 1292/07) and the FIRST Program of the Israel Science Foundation (grant no. 1514/07). The authors are also grateful to G. Molev for fruitful discussions and D. Milstein for ongoing support.
Author information
Authors and Affiliations
Contributions
Y.T. designed and performed the experiments, and wrote the manuscript. M.A.I. performed the DFT calculations. M.B. collected single-crystal X-ray crystallographic data and solved the structures. M.G. designed and managed the project.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary information
Supplementary information (PDF 479 kb)
Supplementary information
Crystallographic data for compound 4a (CIF 22 kb)
Supplementary information
Crystallographic data for compound 6 (CIF 21 kb)
Supplementary information
Crystallographic data for compound 10a (CIF 21 kb)
Supplementary information
Crystallographic data for compound 11a (CIF 33 kb)
Rights and permissions
About this article
Cite this article
Tulchinsky, Y., Iron, M., Botoshansky, M. et al. Nitrenium ions as ligands for transition metals. Nature Chem 3, 525–531 (2011). https://doi.org/10.1038/nchem.1068
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nchem.1068
This article is cited by
-
Structural, electronic and reactivity studies on group 15 analogues of N-heterocyclic carbene
Structural Chemistry (2015)