Reference : Synthesis and Catalytic Evaluation of Ruthenium-Arene Complexes Bearing Imidazol(in)i...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/105986
Synthesis and Catalytic Evaluation of Ruthenium-Arene Complexes Bearing Imidazol(in)ium-2-thiocarboxylate Ligands
English
Hans, Morgan mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie macromoléculaire et catalyse organique]
Willem, Quentin mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie macromoléculaire et catalyse organique]
Wouters, Johan [> > > >]
Demonceau, Albert mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie macromoléculaire et catalyse organique]
Delaude, Lionel mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie organométallique et catalyse homogène]
2011
Organometallics
American Chemical Society
30
22
6133-6142
Yes (verified by ORBi)
International
0276-7333
1520-6041
Washington
DC
[en] Five new complexes with the generic formula [RuCl(2)(p-cymene)(SOC.NHC)] (2-6) were isolated in high yields by reacting the [RuCl(2)(p-cymene)](2) dimer with a range of imidazol(in)ium-2-thiocarboxylate zwitterions bearing cyclohexyl, 2,4,6-trimethylphenyl (mesityl), or 2,6-diisopropylphenyl groups on their nitrogen atoms in CH(2)Cl(2) at -20 degrees C. All the products were fully characterized by IR and NMR spectroscopy, and the molecular structures of [RuCl(2)(p-cymene)(SOC.IMes)] (3) and [RuCl(2)(p-cymene)(SOC.SIMes)] (5) were determined by X-ray diffraction analysis. Coordination of the NHC.COS ligands took place via the sulfur atom. A remarkable shielding of the methine proton on the p-cymene isopropyl group was observed by (1)H NMR spectroscopy for complexes 3-6. It is most likely caused by the aromatic ring current of a neighboring mesityl or 2,6-diisopropylphenyl substituent. The catalytic activity of compounds 2-6 was probed in the ring-opening metathesis polymerization (ROMP) of cyclooctene, in the atom transfer radical polymerization (ATRP) of methyl methacrylate, and in the synthesis of enol esters from 1-hexyne and 4-acetoxybenzoic acid. In all these reactions, the [RuCl(2)(p-cymene)(SOC.NHC)] complexes displayed performances slightly inferior to those exhibited by [RuCl(2)(p-cymene)(NHC)] species that result from the reaction of [RuCl(2)(p-cymene)](2) with NHC.CO(2) inner salts. However, they were significantly better catalyst precursors than the much more robust chelates of the [RuCl(p-cymene)(S(2)C.NHC)PF(6) type obtained by coordination of NHC.CS(2) betaines to the ruthenium dimer. These results suggest that the Ru-(SOC.NHC) motif undergoes a dethiocarboxylation under the experimental conditions adopted for the catalytic tests and leads to the same elusive Ru-NHC active species as the preformed [RuCl(2)(p-cymene)-(NHC)] family of complexes.
Researchers ; Professionals
http://hdl.handle.net/2268/105986
10.1021/om2006529

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