The ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate [BMIm][BF4] has demonstrated high efficiency when applied as a solvent in the oxidative nitro‐Mannich carbon? carbon bond formation. The copper‐catalyzed cross‐dehydrogenative coupling (CDC) between N‐phenyltetrahydroisoquinoline and nitromethane in [BMIm][BF4] occurred with high yield under the described reaction conditions. Both the ionic liquid and copper catalyst were recycled nine times with almost no lost of activity. The electrochemical behavior of the tertiary amine substrate and β‐nitroamine product was investigated employing [BMIm][BF4] as electrolyte solvent. The potentiostatic electrolysis in ionic liquid afforded the desired product with a high yield. This result and the cyclic voltammetric investigation provide a better understanding of the reaction mechanism, which involves radical and iminium cation intermediates. 相似文献
Supramolecular ionogels were prepared by the gelation of room‐temperature ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF4]) with (S,S)‐bis(leucinol)oxalamide. Remarkably, the ionic conductivity of solutions and ionogels with low gelator concentrations is higher than that of neat [BMIm][BF4]. On the basis of molecular dynamics simulations and quantum mechanical calculations, the origin of this phenomenon is attributed to the higher affinity of gelator molecules towards [BF4]? ions, which reduces the electrostatic attraction between [BMIm]+ and [BF4]? and thus increases their mobility. With increasing gelator concentration, the ionic conductivity decreases due to the formation of a denser gelator matrix, which hinders the pathways for ionic transport. However, even for very dense ionogels, this decrease is less than one order of magnitude relative to neat [BMIm][BF4], and thus they can be classified as highly conductive materials with strong potential for application as functional electrolytes. 相似文献
The effect of electrochemical reduction of CO2 on the structure and morphology of titanium(IV) oxide thin films was examined after a fixed-potential bulk electrolysis process.
Films deposited on ITO (Indium-Tin Oxide) substrates were used as the working electrodes and 1-butyl-3-methylimidazolium tetrafluoroborate
([BMIm][BF4]) as solvent and as supporting electrolyte. Grazing incidence X-ray diffraction analysis performed before and after the electrolysis
process indicated no microstructural changes of the anatase films. X-ray photoelectron spectroscopy revealed peaks associated
with adsorbed carbonate ions at 288 eV and CO2 species at 293 eV, whereas Ti2p peaks displacements for CO2-saturated TiO2/ITO surfaces in [BMIm][BF4] revealed chemical bonding effects. Auger electron spectroscopy revealed a high carbon content on CO2-exposed films, and suggested a strong chemisorption of CO2 and CO32− species on the TiO2/ITO surface in [BMIm][BF4] solvent system. A significant decrease in carbon content after bulk electrolysis indicated that the CO2 electroreduction process is not controlled by either diffusion or by adsorption of CO2 on the TiO2/ITO electrode surface. 相似文献
The molecular interactions of the ionic liquids (ILs) 1‐butyl‐3‐methylimidazolium tetrafluoroborate [C4mim][BF4], 3‐methyl‐1‐octylimidazolium tetrafluoroborate [C8mim][BF4] and 1‐butyl‐3‐methylimidazolium octylsulfate [C4mim][C8OSO3] are investigated in ethylene glycol (EG) over the whole mole fraction range using fluorescence (steady‐state and time‐resolved), Fourier transform infrared and nuclear magnetic resonance (NMR) spectroscopy. The cybotactic region surrounding the pyrene fluorescent probe exhibits peculiar characteristics for different ILs in the EG‐rich region. The extent of solute–solvent interactions is assessed by determining the deviations of experimentally observed vibronic band intensity ratios of peak 1 to peak 3 of pyrene fluorescence (I1/I3) from a composite I1/I3 value obtained using a preferential solvation model. A distinct vibrational frequency shift for various stretching modes of EG (O? H) or ILs (C? H of ring protons, B? F and S?O of anions) indicates specific interactional preferences of EG toward the IL protons/anion. Splitting of the O? H vibration band of EG at 3000–3700 cm?1 into three separate bands, and analysis of the changes in location and area of these bands as a function of concentration enable precise determination of the effect of ILs on hydrogen bridges of EG. NMR chemical shifts and their deviations from ideality show multiple hydrogen‐bonding interactions of varying strengths between unlike molecules in the mixtures. A comparison of spectroscopic results with thermodynamic properties shows that the mixing microscopic behaviour of the investigated systems is completely different from the macroscopic behaviour, which is primarily governed by the difference in shape, size and nature of the molecules. 相似文献
The enzymatic resolution of (RS)-methyl mandelate with n-butylamine using lipases in organic solvents (n-hexane, tert-butanol, and chloroform) and ionic liquids [BMIm][BF4] and [BMIm][PF6] is reported. The amide configuration is dependent on the organic solvent. When using mixtures of chloroform or tert-butanol/ionic liquids (10:1 v/v) with CAL-B as the catalyst, the amides were obtained in high enantiomeric excess (eep >99% and E >200). 相似文献
Highly conductive poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films as transparent electrodes for organic light‐emitting diodes (OLEDs) are doped with a new solvent 1,3‐dimethyl‐2‐imidazolidinone (DMI) and are optimized using solvent post‐treatment. The DMI doped PEDOT:PSS films show significantly enhanced conductivities up to 812.1 S cm−1. The sheet resistance of the PEDOT:PSS films doped with DMI is further reduced by various solvent post‐treatment. The effect of solvent post‐treatment on DMI doped PEDOT:PSS films is investigated and is shown to reduce insulating PSS in the conductive films. The solvent posttreated PEDOT:PSS films are successfully employed as transparent electrodes in white OLEDs. It is shown that the efficiency of OLEDs with the optimized DMI doped PEDOT:PSS films is higher than that of reference OLEDs doped with a conventional solvent (ethylene glycol). The results present that the optimized PEDOT:PSS films with the new solvent of DMI can be a promising transparent electrode for low‐cost, efficient ITO‐free white OLEDs.
Phthalic anhydride reacts rapidly with Aromatic and aliphatic amines in ionic liquid [Bmim][PF6] or [Bmim][BF4] at 130 °C to give N‐aryl and N‐alkylphthalimides in excellent yields. 相似文献
CuI‐catalyzed coupling reactions of aryl iodides and electron‐deficient aryl bromides with nitrogen‐containing reagents, such as imidazole, benzimidazole, aliphatic primary and secondary amines, aniline, primary and secondary amides, in ionic liquid were developed. The reaction conditions involved the use of [Bmim][BF4] as the solvent, potassium phosphate as the base, and CuI as the catalyst. The CuI and [Bmim][BF4] could be recovered and recycled for five consecutive trials without significant loss of their activity. 相似文献
Seven compounds with binary or ternary Ge/Se, Ge/Sn/Se, or Sn/Se anionic substructures crystallized upon the ionothermal reactions of [K4(H2O)3][Ge4Se10] with SnCl4 ? 5 H2O or SnCl2 in [BMMIm][BF4] or [BMIm][BF4] (BMMIm=1‐butyl‐2,3‐dimethyl‐imidazolium, BMIm=1‐butyl‐3‐methyl‐imidazolium). The products were obtained by subtly varying the reaction conditions; the nature and amount of an additional amine was the most important parameter in the product selection and in determining the Sn/Ge ratio in the isolated products. The crystal structures of these chalcogenides were based on complex anions with unprecedented topologies that varied from discrete clusters (0D) through 1D chain structures or 2D layers to 3D frameworks. The architecture and composition of the title compounds were well reflected by their optical absorption behavior. Herein, we report a convenient approach for the generation of chalcogenidometallate phases with fine‐tunable electronic properties in ionic liquids, which have been inaccessible by traditional methods. 相似文献