Synthesis and complexations of a novel stable carbene bearing a phosphorus ylide

Article abstract of DOI:10.1080/10426500701795167

Rh complexes 5 and 6 were synthesized via the titled carbine 1. In the IR spectrum of 6, the carbonyl stretching frequency was observed at the lower wave number among all [(carbene)Rh(CO)2Cl] complxes reported to date, including the highest electron-donating ability of carbene 1. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500701795167

This article was downloaded by: [University of Auckland Library]
On: 10 December 2014, At: 17:11
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
Synthesis and Complexations of
a Novel Stable Carbene Bearing
a Phosphorus Ylide
a
a
Shin-ya Nakafuji , Junji Kobayashi & Takayuki
a
Kawashima
a
Department of Chemistry , Graduate School of
Science, The University of Tokyo , Bunkyo-ku, Tokyo,
Japan
Published online: 20 Jun 2008.
To cite this article: Shin-ya Nakafuji , Junji Kobayashi & Takayuki Kawashima (2008)
Synthesis and Complexations of a Novel Stable Carbene Bearing a Phosphorus Ylide,
Phosphorus, Sulfur, and Silicon and the Related Elements, 183:2-3, 642-643, DOI:
10.1080/10426500701795167
To link to this article: http://dx.doi.org/10.1080/10426500701795167
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,
or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with
primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or

indirectly in connection with, in relation to or arising out of the use of the
Content.
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 183:642–643, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701795167
Synthesis and Complexations of a Novel Stable Carbene
Bearing a Phosphorus Ylide
Shin-ya Nakafuji, Junji Kobayashi, and Takayuki
Kawashima
Department of Chemistry, Graduate School of Science, The University of
Tokyo, , Bunkyo-ku, Tokyo, Japan
Rh complexes 5 and 6 were synthesized via the titled carbine 1. In the IR spectrum
of 6, the carbonyl stretching frequency was observed at the lower wave number
among all [(carbene)Rh(CO) Cl] complxes reported to date, including the highest
2
electron-donating ability of carbene 1.
Keywords Carbene ligands; carbenes; phosphorus rhodium; ylides
1
Since the first report by Arduengo in 1991, N-heterocyclic carbenes
(
NHCs) have been extensively studied. Through their successful appli-
cation as ligands for transition metal catalysts, the tuning of electronic
and structural properties of NHCs has become an important subject.
One of the modification methods of NHCs is the replacement of amino
groups adjacent to the carbene center to other π-donating substituents.
Thus, we have focused our attention on carbene 1, which has a phos-
phorus ylide moiety next to the carbene center. Due to π-donation abil-
ity of the ylide carbanion to the carbene center like an amino group
and smaller electronegativity of carbon than that of nitrogen, 1 is ex-
pected to have a strong electron-donating ability to the metal center in
its transition metal complexes. Although several transition metal (Pt,
2
Cr, Mo, W) complexes of carbene 1 (R = H) were reported, they were
synthesized from the corresponding isocyanide complexes, and avail-
able metals were limited. Herein, we report the development of the
general synthetic method of carbene 1 (R = CH3) and its coordinating
properties.
Reaction of phosphonium salt
2 with mesityllithium gave
diphenylphosphine 3 as a major product. Diphenylphosphine 3 is
Address correspondence to Takayuki Kawashima, Department of Chemistry, Gradu-
ate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033,
Japan. E-mail:takayuki@chem.s.u-tokyo.ac.jp
6
42

Novel Stable Carbene
643
considered to be formed by 1,3-phenyl shift via carbene 1. At lower
temperature, however, carbene 1 could be trapped by elemental sulfur
to give 4, quantitatively.
To evaluate the ligand property of carbene 1, rhodium complexes 5
and 6 were prepared. Both 5 and 6 are air stable in the solid state.
Carbonyl stretching frequencies of 6 were observed at the lowest wave
numbers among analogous carbene rhodium complexes, indicating that
carbene 1 has a strong electron-donating ability.
REFERENCES
[
[
1] J. Arduengo, III, R. L. Harlow, M. Kline, J. Am. Chem. Soc., 113, 361 (1991).
2] R. A. Michelin, A. J. L. Pombeiro, and M. F. C. Guedes da Silva, Coord. Chem. Rev.,
218, 75 (2001).