The catalytic roles of ionic liquids (ILs) in the syntheses of 1,3-disubstituted ureas from the carboxylation of amines by CO(2) were experimentally and theoretically investigated. The carboxylation reaction of n-butylamine was greatly facilitated by the presence of an IL and the catalytic activity of the IL was strongly affected by the nucleophilicity of the anion. Computational study on the mechanistic aspects of the carboxylation with methylamine with or without the presence of an IL, 1-ethyl-3-methylimidazolium chloride, implies that the activation energies of the transition states and the intermediate ionic species could be lowered significantly through the multi-interactions of the carbonyl group of CO(2) with both cations and anions of the ILs.
The reduced graphene oxides (RGOs) functionalized by pyridinium-based ionic liquids (ILs) with SCN anions revealed 6-fold higher capacitance compared to that of RGOs due to the redox behavior of ILs as well as good rate capability and cycle stability despite the appearance of pseudo-capacitance.
Asymmetric alkyl substitution of various benzophenone Schiff base substrates under biphasic conditions proceeded using optically active Palladium(II) complexes. The corresponding products were obtained in high yields but with moderate enantiomeric excess (ee). Addition of specific ionic liquids to the reaction medium enhanced reactivity and selectivity for phase transfer catalytic (PTC) glycine alkylation. It has been found that there is an anionic influence of the ionic liquids that modify the steric environment around the enolate ion. A computer-assisted molecular design of enantioselective phase-transfer catalysis with the palladium complex and the ionic liquid has been done.
The asymmetric C-alkylation of benzophenone Schiff base glycine esters has been achieved using a palladium(II) chiral complex as a phase-transfer catalyst. The aromatic moiety around the metal center and various physicochemical parameters were investigated to study their effect on the asymmetric alkylation reaction under phasetransfer conditions. Moderate enantioselectivity(30-40%) was achieved under room temperature conditions, which is a significant improvement compared to no enantioselectivity with a chiral palladium-salen complex reported earlier. Computer simulation studies indicate that coordination of the metal center with Z-enolate forming a square planar complex provides a favorable steric environment where the a-carbon atom of the enolate is available for enantioselective alkylation.Electronic supplementary material The online version of this article (
− anion, the specific capacitance of ILs bearing [DCNAcC] − anion are higher than that of IL containing [Tf 2 N] − anion and showed high temperature dependence. Such favorable electrochemical properties of these ILs are likely to be attributed to the efficient dissociation of cation and anion at higher temperature and enhanced electrosorption of [DCNAcC] − anion at the electrode.
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