The modification of the surface chemistry of heterogeneous catalysts/supports alters their electronic and catalytic properties, particularly through the incorporation of a monolayer of sophisticated N-heterocyclic carbenes (NHCs). However, the formation of aluminum N-heterocyclic carbene (NHC-Al) goes unrecognized or remains unidentified when imidazolium-based ionic liquids are supported on solids (SILPs). In this work, we identified the formation of NHC-Al species upon the grafting of imidazolium-based ILs onto neutral Al2O3. The optimal geometry of the imidazolium cations in these SILPs adopts a tilted orientation, exhibiting an upright binding mode, akin to self-assembled monolayers (SAMs). This configuration enables direct interaction of the electron-rich N-C-N moiety of the imidazolium cation with the Al2O3 surface, leading to the autocatalytic formation of NHC-Al species. The NHC-Al species are confirmed through solid-state 13C NMR, 13C-1H HETCOR, 27Al NMR, synchrotron XPS, XANES, and DFT calculations. This study provides unique insights into the bonding and structural geometry of ILs in SILPs, revealing features that have previously gone unobserved.

The zwitterions resulting from the covalent attachment of 3- or 4-hydroxy benzene to the 1,3-dimethylimidazolium cation represent basic compounds (pKa of 8.68 and 8.99 in aqueous solutions, respectively) that chemisorb in aqueous solutions 0.58 mol/mol of carbon dioxide at 1.3 bar (absolute) and 40 °C. Equimolar amounts of chemisorbed CO2 in these solutions are obtained at 10 bar and 40 °C. Chemisorption takes place through the formation of bicarbonate in the aqueous solution using imidazolium-containing phenolate. CO2 is liberated by simple pressure relief and heating, regenerating the base. The enthalpy of absorption was estimated to be -38 kJ/mol, which is about 30 % lower than the enthalpy of industrially employed aqueous solutions of MDEA (estimated at -53 kJ/mol using the same experimental apparatus). The physisorption of CO2 becomes relevant at higher pressures (>10 bar) in these aqueous solutions. Combined physio- and chemisorption of up to 1.3 mol/mol at 40 bar and 40 °C can be attained with these aqueous zwitterionic solutions that are thermally stable and can be recycled at least 20 times.

We present a series of newly designed 2,1,3-benzothiadiazole (BTD)-containing imidazole(ium) derivatives that are selective live cell fluorescence imaging probes applied in bioimaging experiments. The attachment of imidazole(ium) moieties that are planar, rigid, flat and displays strong hydrogen bond sites allows modulating the physicochemical properties of the resulting fluorescent bioimaging molecular probes which are water-soluble at room temperature. The photophysical characterization revealed the high stability of those derivatives in both the ground and excited states meaning the relaxation processes take place with no degradation. DFT calculations showed the orbital behavior of the fluorescent compounds pointing to the origin of the high chemical stability of such compounds in their relaxation processes from the excited states (no degradation noted). Live cell fluorescence imaging experiments (MCF-7 breast cancer cell lineage and other types) showed a high subcellular selection inside the cells and lysosomes could be selectively stained. Bioimaging experiments also revealed that all compounds were capable of transpose the cellular membrane and one of them showed impressive selection towards lysosomes with intense, bright and green fluorescence. The BTD derivatives proved to be cell penetrating and stable in solution storage at room temperature, which represents a huge advance over the commercially available cellular markers.

Simple and single step ionic liquid assisted solvothermal method is proposed for synthesis of CdS@MoS2 core–shell nanospheres. The formation of core–shell structure can be attributed to 1-triethylene glycol monomethyl ether-3-methylimidazolium methanesulfonate ionic liquid added during the synthesis. Several physicochemical techniques were exercised to validate the desired state of the obtained material. Generally, implementation of CdS as anode for lithium ion batteries is truncated by its low theoretical capacity. Herein, we introduce CdS@MoS2 core–shell nanospheres to account this issue. MoS2, a layered material with high capacity and good stability, is selected as an appropriate material to form a p-n junction by encapsulation of CdS nanospheres. For the first time, CdS@MoS2 is probed as an anode for lithium ion batteries. At very high current rate of 0.2 C, the electrode delivered a high discharge capacity of 734 mA h g−1 after 100 cycles. The excellent electrochemical properties of CdS@MoS2 core–shell nanospheres including high specific capacity and high stability are ascribed to the encapsulation of CdS nanospheres with amorphous MoS2.

The fabrication of surface clean palladium nanoparticles of 3–4nm was accomplished in imidazolium-based functionalized ionic liquids (ILs) having methoxy, cyano, and thio groups by magnetron sputtering deposition. The size of the NPs was strongly dependent on the surface composition and/or organisation of the ILs. The NP growth apparently occurred preferentially in the bulk of the fluids, whereas nucleation apparently occurred preferentially at the IL surface. Smaller NPs were detected close to the methoxy containing IL surface and were covered by at least one layer of IL ion pairs, as revealed by high-sensitivity low-energy ion scattering (HS-LEIS) measurements.

A simple and odorless route for the synthesis of monocationic and dicationic thiaalkylimidazolium ionic liquids (ILs) is reported. Our approach starts with the selective monoalkylation of dihalogenated substrates by methylimidazole derivatives, followed by the synthesis of odorless isothiouronium salts via reaction with thiourea. The target ILs are obtained after sequential hydrolysis-alkylation of the isothiouronium salts followed by anion metathesis in water. After extraction, the novel thiaalkylimidazolium ILs are obtained with high purity, without the requirement of additional purification steps. In order to demonstrate their applicability, two of these task-specific ILs were employed as ligands in Ullmann and Suzuki couplings and also as charged probes to detect copper intermediates via ESI(+)-MS. (C) 2019 Elsevier Ltd. All rights reserved.

Simple 1,2,3-trialkylimidazolium cation associated with basic anions, such as hydrogen carbonate, prolinate, and imidazolate, is an active catalyst for the H/D exchange reaction of various substrates using CDCl3 as D source, without the addition of any extra bases or metal. High deuterium incorporation (up to 49%) in acidic C-H bonds of ketone and alkyne substrates (pK(a) from 18.7 to 28.8) was found at room temperature. The reaction proceeds through the fast and reversible deuteration of the 2-methyl H of the imidazolium cation followed by D transfer to the substrate. The IL acts as a neutral base catalyst in which the contact ion pair is maintained in the course of the reaction. The basic active site is due to the presence of a remote basic site in the anion namely, OH of bicarbonate, NH of prolinate, and activated water in the imidazolate anion. Detailed kinetic experiments demonstrate that the reaction is first order on the substrate and pseudozero order relative to the ionic liquid, due to the fast reversible reaction involving the deuteration of the ionic liquid by the solvent.

Negatively charge-tagged N-heterocyclic carbenes have been formed in solution via deprotonation of imidazolium ions bearing acid side groups and transferred to the gas phase via ESI(–)-MS. The structure of the putative and apparently stable gaseous carbenes formed in such conditions were then probed via reactions with carbon dioxide using a triple quadrupole mass spectrometer particularly optimized for ion/molecule reactions of ESI-generated ions. Complete conversion to imidazolium carboxylates was achieved, which seems to demonstrate the efficiency of the transfer, the gas-phase stability, and the long-lived nature of these unprecedented charge-tagged carbenes and their predominance in the ionic population. Comprehensive studies on the intrinsic reactivity of N-heterocyclic carbenes with silent charge tags are therefore possible.

It is well known that the macroscopic physico-chemical properties of ionic liquids (ILs) are influenced by the presence of water that strongly interferes with the supramolecular organization of these fluids. However, little is known about the function of water traces within this confined space and restricted ionic environments, i.e. between cations and anions. Using specially designed ILs namely 1,2,3-trimethyl-1H-imidazol-3-ium imidazol-1-ide (MMMI·Im) and 3-n-butyl-1,2-dimethyl-1H-imidazol-3-ium imidazol-1-ide (BMMI·Im), the structure and function of water have been determined in condensed, solution and gas phases by X-ray diffraction studies, NMR, molecular dynamics simulations (MDS) and DFT calculations. In the solid state the water molecule is trapped inside the ionic network (constituted of contact ion pairs formed by π(+)-π(-) interaction) through strong H-bonds involving the water hydrogens and the nitrogens of two imidazolate anions forming a guest@host supramolecular structure. A similar structural arrangement was corroborated by DFT calculations and MDS. The presence of a guest@host species (H2O@ILpair) is maintained to a great extent even in solution as detected by (1)H-(1)H NOESY-experiments of the ILs dissolved in solvents with low and high dielectric constants. This confined water catalyses the H/D exchange with other substrates containing acidic-H such as chloroform.

The catalytic species generated by dissolving Ru3 (CO)12 in the ionic liquids 1-n-butyl-3-methyl-imidazolium chloride or 1-n-butyl-2,3-dimethyl-imidazolium chloride are efficient multifunctional catalysts for: (a) reverse water-gas shift, (b) hydroformylation of alkenes, and (c) reductive amination of aldehydes. Thus the reaction of alkenes with primary or secondary amines (alkene/amine, 1:1) under CO2 /H2 (1:1) affords the hydroaminomethylations products in high alkene conversions (up to 99 %) and selectivities (up to 96 %). The reaction proceeds under relatively mild reaction conditions (120 °C, 60 bar=6 MPa) and affords selectively secondary and tertiary amines. The presence of amine strongly reduces the alkene hydrogenation competitive pathway usually observed in the hydroformylation of terminal alkenes by Ru complexes. The catalytic system is also highly active for the reductive amination of aldehydes and ketones yielding amines in high yields (>90 %).

The reaction of [BMI center dot Cl] (BMI = 1-butyl-3-methylimidazolium) or [BMMI center dot Cl] (BMMI = 3-butyl-1,2-dimethylimidazolium) with Ru-3(CO)(12) generates Ru-hydride-carbonyl-carbene species in situ that are efficient catalysts for a reverse water gas shift/hydroformylation/hydrogenation cascade reaction. The addition of H3PO4 increased the catalytic activity of the first step (i.e., the hydrogenation of CO2 to CO). Under the optimized reaction conditions [120 degrees C and 6.0 MPa CO2/H-2 (1:1) for 17 h], cyclohexene and 2,2-disubstituted alkenes were easily functionalized to alcohols through sequential hydroformylation/carbonyl reduction.

1-n-Butyl-2,3-dimethylimidazolium (BMMI) ionic liquids (ILs) associated with different anions undergo H/D exchange preferentially at 2-Me group of the imidazolium in deuterated solvents. This process is mainly related to the existence of ion pairs rather than the anion basicity. The H/D exchange occurs in solvents (CDCl3 and MeCN for instance) in which intimate contact ion pairs are present and the anion possesses a labile Hin its structure, such as hydrogen carbonate and prolinate. In D2O, separated ion pairs are formed and the H/D exchange does not occur. A plausible catalytic cycle is that the IL behaves as a neutral base in the course of all H/D exchange processes. NMR experiments, density functional calculations, and molecular dynamics simulations corroborate these hypotheses.

High-sensitivity low-energy ion scattering (HS-LEIS) analysis was used to elucidate the outermost layer of both functionalized and non-functionalized imidazolium ionic liquids (ILs). The IL outermost layer is composed of all atoms of both cations and anions. The HS-LEIS analyses also allow for quantitative measurement of the thickness of IL overlayers on Au nanoparticles prepared by sputter deposition, which was shown to be a monolayer of ions, as predicted by density functional theory calculations.

TiO2 nanoparticles and TiO2–RGO (reduced graphene oxide) composite were synthesized by ionothermal method at 100 and 120°C for 24h using two different ionic liquids (ILs), 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate (IL1) and 1-(2-methoxyethyl)-3-methylimidazolium tetrafluoroborate (IL2). BET surface area analysis of the composites showed surface areas of 170 and 161m2g−1 for TiO2 and TiO2–RGO composite respectively. TEM images show that the sizes of the particles are around 4nm and in the composite clearly show that TiO2 NPs are present on the surface of the graphene sheet. The use of IL2 produces a high crystalline TiO2 NPs with pure anatase phase without need of thermal treatment (TT). Hydrogen generation by UV light on TiO2 NPs or TiO2–RGO composite prepared in ILs without thermal treatment (TT) show lower rate than TiO2 P25. After TT at 400°C a higher H2 production rate (up to 0.76mmolh−1g−1) due to the increase in crystallinity was measured. The photocatalytic activity was further enhanced for TiO2–RGO composite. The electron-accepting and electron-transporting properties of graphene in the composite could indeed suppress the charge recombination and improve their photocatalytic activities.

Anatase TiO2 nanoparticles have been successfully synthesized at 130 °C for 2 days via ionic liquid-assisted hydrothermal method. The obtained products are characterized using various techniques. The X-ray diffraction data reveal that the nanoparticles are anatase TiO2. FTIR spectrum shows that the presence of ionic liquid and indicates Ti–O–Ti peak at around 398 cm−1, and the bands at 1500 and 1600 cm−1 indicates C–H in-plane vibrations and stretching of imidazolium ring. Raman spectroscopy show bands at 142, 393, 513, and 636 cm−1 reveal crystalline anatase phase. UV–Vis spectroscopy shows the λ max at 355 nm corresponding to a band gap of 3.49 eV. TEM images reveal that the average diameters of anatase TiO2 nanoparticles are in the range 50–100 nm. Anatase TiO2 exhibited excellent photocatalysis for the degradation of organic dye.

Benzothiadiazole (BTD) is one of the most important classes of conjugated systems because of their photophysical properties such as high extinction coefficient, intense fluorescence, and large Stokes shift. These features make them useful in a variety of applications such as optical materials and chemosensors. Fluorescent BTD derivatives are used in practical applications, including their utility as laser dyes, emitters in light-emitting diodes, photoconductors, optical data storage, and optical switches. Imidazolium salts have advantageous physicochemical properties, which can be modulated by the use of different cations and anions. In this work we are interested to explore a straightforward synthesis of a new class of luminescent imidazolum salts derived from imidazole-BTD as starting material.

Ruthenium complexes have many applications among them that their use in advanced material synthesis and heterogeneous catalysis. Developing the ligand is of great importance and this is of influence on the yield and selectivity of reaction, and especially to allow reuse of the catalyst. Taskspecific ionic liquids (TSILs) are commonly used as ligands for metallic complexes, due to their easily tunable properties and, specifically, ionophilic ligands can provide the advantages of strong interaction with ionic liquids as solvents, which reduces the loss of catalyst and its subsequent reuse. Tridentate pincer ligands containing the SNS moiety (SCH2CH2NHCH2CH2S) were selected mainly for application in ester hydrogenation/ dehydrogenation reactions.

The interception, formation and characterization of the first stable, long lived charge-tagged N-heterocyclic carbenes of the general type 4x+ (x = 1–3) and analogues is reported. Via ESI(+)-MS of solutions of bromine salts of doubly, triply and quadruply charged imidazolium ion IL (3.Brn, n = 2–4), the isolated 4x+ as well as charged aggregates [3.Br(n−x)]x+ likely to be participating in the [3.Br(n−x)]x+ ⇌ 4x+ + HBr solution equilibrium could be transferred and characterized in the gas phase. Mimicking the solution equilibrium, the gaseous [3.Br(n−x)]x+ were found to dissociate nearly exclusively viaHBr loss during thermal activationvia collisions to form gaseous 4x+, which were found to add to acrolein and acetone.

The new silylant agent 3-(N,N′-dicyclohexylguanidine)-propyltrimethoxysilane (GPMS) was prepared straightforwardly in high yield by the simple reaction between 3-aminopropyltrimethoxysilane and dicyclohexylcarbodiimide. This new organosilane containing the basic dicyclohexylguanidine group covalently attached on silica gel is an efficient heterogeneous catalyst for the production of biodiesel. Conversions up to 98% were obtained for soybean oil methanolysis at 353 K for 3 h. This catalytic system was transposed to a semi-pilot scale in a continuous flow reactor and gave 44% conversion. The calculated activation energy of the methanolysis in this continuous system indicated that the reaction is probably under mass transfer limitations.

Travelling-wave ion mobility mass spectrometry was used to measure the intrinsic mobility of a series of gaseous supra-cation and supra-anion aggregates of several ionic liquids. Close mobilities were observed in a T-wave cell filled with helium at ca. 0.8 mbar for [(DAI)(n+1)(X)(n)](+) (DAI is the 1,3-dialkylimidazolium cation and X is the anion) as compared to the respective anions [(DAI)(n)(X)(n+1)](-) for n=0 to 9. The anomalous behavior reported before in the condensed phase seems therefore to be related to the unique structural organization of pure ionic liquids that provides both polar and non-polar regions with directionality in which the anionic species are more retained than the cationic species in the salt network.