157197-54-1Relevant articles and documents
Haloaurate and halopalladate imidazolium salts: Structures, properties, and use as precursors for catalytic metal nanoparticles
Serpell, Christopher J.,Cookson, James,Thompson, Amber L.,Brown, Christopher M.,Beer, Paul D.
, p. 1385 - 1393 (2013)
The synthesis and characterisation of a series of new gold- and palladium-containing symmetrical imidazolium salts are described which display significant cation-dependent effects determined by the structure of the alkyl chains of the imidazolium motifs. Whereas direct reduction of the Pd salts can produce stable nanoparticles (NPs) coated by imidazolium salts, the addition of strong base to the Pd or Au salts before reduction gives stable NPs, potentially pacified by N-heterocyclic carbene units. The possibility of NP surface protection by metal-carbon bonds in these systems is investigated by spectroscopic, synthetic, and catalytic investigations, providing support for the hypothesis. Significantly, the catalytic activity of the NPs is not inhibited by the continued presence of the ligands. The Royal Society of Chemistry 2013.
An acidity scale of 1,3-dialkylimidazolium salts in dimethyl sulfoxide solution
Chu, Yuan,Deng, Hui,Cheng, Jin-Pei
, p. 7790 - 7793 (2007)
(Chemical Equation Presented) Equilibrium acidities of 16 1,3-dialkylimidazolium-type ionic liquid (IL) molecules (1-16) were systematically measured by the overlapping indicator method at 25°C in dimethyl sulfoxide (DMSO) solution. The pKa values were observed to range from 23.4 for IL 12 to 19.7 for IL 6 (Tables 1 and 2), responding mainly to structural variations on the cation moiety. Excellent agreement between the spectrophotometrically determined pKa and that derived from NMR titration for 1,3,4,5-tetramethylimidazolium bis(trifluoromethanesulfonyl)imide (12) and the close match of the obtained pK values with the reported data in literature provide credence to the acidity measurements of the present work. The substituent effects at the imidazolium ring and the effects of counterions on the acidities of ionic liquids are discussed.
Synthesis of bis-N-alkyl imidazolium salts and their palladium(0)(NHC) (η2-MA)2 complexes
Tromp, Dorette S.,Hauwert, Peter,Elsevier, Cornelis J.
experimental part, p. 335 - 341 (2012/08/08)
New N-Alkyl-substituted imidazolium salts as well as a series of their corresponding [Pd(NHC)(MA)2] complexes have been obtained by three routes in good yield. The previously reported synthesis for the analogous N-aryl substituted [Pd(NHC)(MA)2] complexes has been improved. The N-alkyl-substituted [Pd(NHC)(MA)2] complexes are thermally more labile than their N-aryl counterparts. Catalytic transfer semi-hydrogenation of phenylpropyne resulted in good to excellent chemo- and stereo- selectivity conversion into (Z)-phenylpropene. The size of the alkyl substituents correlates with the rate of hydrogenation in the sense that more bulky substituents give rise to faster transfer hydrogenation rates. Copyright
