Triphilic ionic-liquid mixtures: fluorinated and non-fluorinated aprotic ionic-liquid mixtures

We present here the possibility of forming triphilic mixtures from alkyl- and fluoroalkylimidazolium ionic liquids, thus, macroscopically homogeneous mixtures for which instead of the often observed two domainspolar and nonpolarthree stable microphases are present: polar, lipophilic, and fluorous ones. The fluorinated side chains of the cations indeed self-associate and form domains that are segregated from those of the polar and alkyl domains. To enable miscibility, despite the generally preferred macroscopic separation between fluorous and alkyl moieties, the importance of strong hydrogen bonding is shown. As the long-range structure in the alkyl and fluoroalkyl domains is dependent on the composition of the liquid, we propose that the heterogeneous, triphilic structure can be easily tuned by the molar ratio of the components. We believe that further development may allow the design of switchable, smart liquids that change their properties in a predictable way according to their composition or even their environment

Ab Initio Molecular Dynamics Simulations of Ionic Liquids

We present ab initio molecular dynamics simulations of the ionic liquids 1-butyl-3-methylimidazolium trifluoromethanesulfonate and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate. We compare the trajectories regarding the formation of hydrogen bonds and the microheterogeneity due to polar and nonpolar phases

On the Carbene-Like Reactions of Imidazolium Acetate Ionic Liquids: Can Theory and Experiments Agree?

The N-heterocyclic carbene organocatalytic reactivity of the 1-ethyl-3-methylimidazolium acetate ionic liquid was investigated on the model reaction between this solvent and anisaldehyde. The formation of carbenes by a proton transfer from the cation to the anion was compared to a direct reaction mechanism, in which the proton transfer and the C-C bond formation between catalyst and substrate occurs in a single elementary step. Interestingly, the two reaction mechanisms show a much smaller difference in activation energies than those observed for analogous catalytic systems with neutral bases, showing that the mechanism might switch from one to the other at different temperatures or with different substrates. In this particular case, however, the direct reaction mechanism, avoiding free carbenes in the solution, is apparently more feasible. Based on the detailed analysis of this reaction path, the earlier contradictions between theory and experiments can be resolved, resulting in a consistent mechanistic picture for the related processes. Additionally, we show on the example of a platinum surface that introducing metal probes into the liquid may induce carbene-like reactions, as the formation of a strong coordinative bond between the carbene and a platinum atom at the surface is highly exothermic, shifting the acid-base equilibrium considerably

Theoretical Investigation of the Te₄Br₂ Molecule in Ionic Liquids

Material synthesis in ionic liquids, at or near room temperature, is currently a subject of immense academic interest. In order to illuminate molecular-level details and the underlying chemistry, we carried out molecular simulations of a single Te4Br2 molecule dissolved in the ionic liquid 1-ethyl-3-methylimidazolium chloride, as well as in the ionic liquid mixed with aluminum chloride. Although the ethyl side chain is much too short to show detailed microheterogeneity, significant structuring with the small chloride anions is seen in case of the pure ionic liquid. In the case of the mixture, formation of larger anionic clusters is distinctly observed and analyzed. Due to the tendency of ionic liquids to dissociate, there is a pronounced shift to elongated Te-Br distances in both investigated solvents. However, only in the AlCl3-containing liquid, we observe the reaction of the open chain-like Te4Br2 molecule to a closed square-like Te4Br+ and AlCl3Br- ion. The molecular arrangement of the [Te-4](2+) unit shows negligible deviation from that in the experimental crystal structure

CO₂-catalyzed efficient dehydrogenation of amines with detailed mechanistic and kinetic studies.

CO2-catalyzed dehydrogenation of amines has been achieved under photocatalytic conditions. With this concept, various amines have been selectively dehydrogenated to the corresponding imines in the presence of different functional groups such as nitrile, nitro, ester, halogen, ether, thioether, and carbonyl or carboxylic acid moieties. At the end, the CO2-catalyzed synthesis of pharmaceutical drugs has been achieved. The CO2 radical has been detected by EPR spectroscopy using DMPO, and the mechanism of this reaction is proposed on the basis of DFT calculations and experimental evidence