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Transition Metal Diazoalkane Complexes. Synthesis, Structure, and Photochemistry of Rh[C(N_2)SiMe_3](PEt_3)_3

Deydier, Eric and Menu, Marie-Joëlle and Dartiguenave, Michèle and Dartiguenave, Yves and Simard, Michel and Beauchamp, André L. and Brewer, John C. and Gray, Harry B. (1996) Transition Metal Diazoalkane Complexes. Synthesis, Structure, and Photochemistry of Rh[C(N_2)SiMe_3](PEt_3)_3. Organometallics, 15 (4). pp. 1166-1175. ISSN 0276-7333. doi:10.1021/om950490h.

[img] PDF (Temperature factors, parameters of the hydrogen atoms, and bond distances and angles for 1 and 5, 31P NMR spectra and COSY 31P−31P NMR spectrum of 1 and geometry of the disordered phosphine and isocyanide ligands for 5) - Supplemental Material
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Reaction of RhCl(PR_3)_n (R = Me (n = 4), Et (n = 3)) and RhCl(CO)(PEt_3)_2 with (trimethylsilyl)diazomethyl lithium at −78 °C in ether yields the three complexes Rh[C(N_2)SiMe_3](PEt_3)_3 (1), Rh[C(N_2)SiMe_3](PMe_3)_4 (2), and Rh[C(N_2)SiMe_3](CO)(PEt_3)_2 (3). 2 could not be isolated as a solid at room temperature but 1 was precipitated as red crystals that were stable enough to be handled under argon. X-ray work on 1 reveals a tetrahedrally distorted square-planar geometry with the planar (trimethylsilyl)diazomethyl ligand roughly perpendicular to the P3RhC coordination plane. This distortion makes the PEt3 ligands nonequivalent in the crystal and produces an ABB‘X pattern in the solid-state ^(31)P NMR spectrum. Photolysis of Rh[C(N_2)SiMe_3](PEt_3)_3 leads quantitatively to the dimer [Rh{C(SiMe_3)(PEt_3)}(PEt_3)_2]_2 (4). The presence of the two ylide bridges and terminal phosphines is deduced from the COSY ^(31)P−^(31)P NMR spectrum. This photochemical reactivity suggests that the transient carbene (PEt_3)_3RhC̈(SiMe_3) is electrophilic, which is typical of a singlet carbene. We believe the singlet state is stabilized by the presence of the electron-rich low-spin Rh(PEt3)3 fragment. Reaction with ^nBuNC and ^tBuNC leads to stereo- and regioselective formation of a triazole that is σ bonded to the rhodium center. The X-ray structure of the ^tBuNC derivative Rh[CC(SiMe_3)N_2N^tBu](^tBuNC)_2(PEt_3) (5) shows a distorted square-planar geometry around Rh with the planar triazolato ligand roughly orthogonal to this plane. The probable reaction mechanism involves addition and substitution reactions of isocyanides at Rh followed by insertion into the Rh−C bond.

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Gray, Harry B.0000-0002-7937-7876
Alternate Title:Transition Metal Diazoalkane Complexes. Synthesis, Structure, and Photochemistry of Rh[C(N2)SiMe3](PEt3)3
Additional Information:© 1996 American Chemical Society. Received June 26, 1995. M.J.M thanks the Ministère des Affaires Etrangères, the Ministère de l'Education du Québec (Projet Intégré FranceQuébec), and the Université de Montréal (Canada) for financial support (postdoctoral fellowship). This work was made possible by travel grants in the framework of the NATO Research Program for International Cooperation between M.D. and H.B.G. (890109). Material support through the Centre National de la Recherche Scientifique, the Université P. Sabatier, and the Natural Sciences and Engineering Reseach Council of Canada is also gratefully acknowledged. Research at Caltech was supported by the National Science Foundation. Contribution 8773 from the Division of Chemistry and Chemical Engineering, California Institute of Technology.
Funding AgencyGrant Number
Ministère de l'Education du QuébecUNSPECIFIED
Université de MontréalUNSPECIFIED
North Atlantic Treaty Organization (NATO)890109
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Université P. SabatierUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
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Division of Chemistry and Chemical Engineering8773
Issue or Number:4
Record Number:CaltechAUTHORS:20180518-163458007
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Official Citation:Transition Metal Diazoalkane Complexes. Synthesis, Structure, and Photochemistry of Rh[C(N2)SiMe3](PEt3)3 Eric Deydier, Marie-Joëlle Menu, Michèle Dartiguenave, Yves Dartiguenave, Michel Simard, André L. Beauchamp, John C. Brewer, and Harry B. Gray Organometallics 1996 15 (4), 1166-1175 DOI: 10.1021/om950490h
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86482
Deposited By: George Porter
Deposited On:21 May 2018 16:23
Last Modified:15 Nov 2021 20:39

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