Reference : Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium-arene c...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/15422
Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium-arene catalysts for olefin metathesis and cyclopropanation
English
Tudose, Adriana [> > > >]
Demonceau, Albert mailto [Université de Liège - ULg > > Chimie macromoléculaire et catalyse organique >]
Delaude, Lionel mailto [Université de Liège - ULg > > Chimie macromoléculaire et catalyse organique >]
2006
Journal of Organometallic Chemistry
Elsevier Science
691
24-25
5356-5365
Yes (verified by ORBi)
International
0022-328X
Lausanne
Switzerland
[en] cyclooctene ; styrene ; ring-opening metathesis polymerization ; cyclopropanation ; homogeneous catalysis
[en] Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,.6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon dioxide. They were characterized by IR and NMR spectroscopies, and by TGA. Their ability to act as NHC precursors for in situ catalytic applications was probed in ruthenium-promoted olefin metathesis and cyclopropanation reactions. When visible light induced ring-opening metathesis polymerization of cyclooctene or cyclopropanation of styrene with ethyl diazoacetate were carried out at 60 degrees C in the presence of [RuCl2(p-cymene)](2), the NHC (.) CO2 adducts and their NHC (.) HX counterparts (X = Cl, BF4) displayed similar activities. When metathesis polymerizations were performed at room temperature, the carboxylates proved far superior to the corresponding imidazol(in)ium acid salts. They displayed the same level of activity as the preformed RuCl2(p-cymene)(IMes) complex, whereas the combination of NHC (.) HX and KO-t-Bu were almost totally inactive. Results obtained for cyclopropanation reactions at room temperature did not show such a large discrepancy of behavior between the two types of adducts. (c) 2006 Elsevier B.V. All rights reserved.
http://hdl.handle.net/2268/15422
10.1016/j.jorganchem.2006.07.035

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Restricted access
A031.pdfPublisher postprint224.09 kBRequest copy

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.