Palladium catalyzed Suzuki C-C couplings in an ionic liquid: nanoparticles responsible for the catalytic activity.
A new family of functionalized ligands derived from norborn-5-ene-2,3-dicarboxylic anhydride has been used in Suzuki C-C cross-couplings between aryl boronic acids and aryl bromide derivatives in [BMI][PF(6)] (BMI=1-n-butyl-3-methyl-imidazolium), using palladium acetate as catalytic precursor. High conversions and yields are obtained when amine ligands containing hydroxy groups are involved. TEM analyses after catalysis show the formation of small nanoparticles, in contrast to the agglomerates observed when nanoparticles are intentionally preformed, with a consequent decrease in the catalytic activity in the latter case. Some tests, including the correlation effect between solvent and ligand, are carried out to try to identify the true nature of the catalyst. All the results obtained suggest that formation of nanoparticles is required to lead to a catalytically active system.
Laboratoire Hétérochimie Fondamentale et Appliquée UMR CNRS 5069, Univesité Paul Sabatier, 118 route de Narbonne, 31062, Toulouse cedex 9, France.
Fernando
F
Fernández
Beatriz
B
Cordero
Jérôme
J
Durand
Guillermo
G
Muller
François
F
Malbosc
Yolande
Y
Kihn
Emmanuelle
E
Teuma
Montserrat
M
Gómez
D002384:Catalysis; D006571:Heterocyclic Compounds / Q000737:chemistry; D007477:Ions; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010165:Palladium / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
D006571:Heterocyclic Compounds; D007477:Ions; D008024:Ligands; D010165:Palladium