Search

This document is a contents list for the New Journal of Chemistry, a publication by The Royal Society of Chemistry. It includes articles covering various topics in chemistry, such as surface modulation of MXenes, synthesis of compounds, and studies on materials and their properties. The journal aims to connect the world with the chemical sciences. The listed papers in this document discuss the electrical and dielectric properties of Na2/3Mn2/3Fe1/3O2 as a cathode material for sodium-ion batteries, a fluorescent probe for monitoring lipid droplets, the effect of cis/trans isomerization on photochromic properties, and the bioactivity of benzophenazine enaminone derivatives as inhibitors of ERK2. [Extracted from the article]

In this paper, we report the unusual aggregation behavior of an important cyanine dye 1,1′-diethyl-4,4′-carbocynine iodide (DECI), also known as kryptocyanine, which interestingly depends on the type of the ionic liquid (IL) present in the aqueous solutions of the dye. Notably, the presence of a small amount of ILs containing [BF4]−, [PF6]− and [OTf]− anions induced the process of J-aggregation instantly, and the added ILs acted as promoters for J-aggregation, followed by time-dependent precipitation. In contrast to the above-mentioned ILs, the presence of a small amount of ILs containing Tf2N− anions induced the process of J- and H-aggregation simultaneously, followed by time-dependent conversion of H-aggregates to J-aggregates. Furthermore, the aggregation behavior of the dye was also found to be dependent on the concentration of the dye, temperature conditions, and nature of solubilizing media (polarity of the solvent and pH). [ABSTRACT FROM AUTHOR]

High-entropy alloys show broad application prospects in electrocatalysis due to their high catalytic activity, conductivity and structural stability. However, achieving their mild and scalable synthesis still remains a great challenge. This paper reports a strategy for the synthesis of CrFeCoNiRu0.5 high entropy nano-alloy/carbon (termed as CrFeCoNiRu0.5-HENA/C) using a chelate-based ionic liquid. Cr(III), Fe(III), Co(II), Ni(II) and Ru(III) were coordinated with salicylic acid ionic liquid to form a viscous metal complex solution, followed by low temperature carbonization and subsequent high temperature annealing. The resulting CrFeCoNiRu0.5- HENA/C consists of a three-dimensional carbon framework and CrFeCoNiRu0.5-HENA nanocrystal. The carbon framework offers high ion/electron conductivity and good affinity with NO3- and CO2 due to the presence of hydrophilic oxygen-containing groups and highly electronegative nitrogen atoms. The CrFeCo-NiRu0.5-HENA nanocrystal has a small size of 52.5 x 1.2 nm, good element homogeneity and high crystallinity. Such a unique structure improves the adsorption capacity towards NO3 - and CO2 and the electrocatalytic activity towards the C-N coupling reaction. The CrFeCoNiRu0.5-HENA/C electrocatalyst exhibits a high urea yield of 35.57 x 0.81 mmol gcatalyst -1 h-1 with a high faradaic efficiency of 21.02-0.77%, which is much better than that of multi-component nano-alloys from Cr, Fe, Co, Ni and Ru. This study also provides an approach for the construction of high-entropy nano-alloys in catalysis, sensing and energy storage and conversion. [ABSTRACT FROM AUTHOR]

The low coulombic efficiency and mild conductivity have impeded the commercialization of sulfur-based batteries despite pairing with high energy density and low-cost aluminum anodes. In this study, we investigated cost-effective electrolyte confinement of the sulfur cathode to an Al/S@Gf battery, which employed a sulfur-graphite (S@Gf) cathode, an aluminum metal anode, and 1-ethyl-3-methyl imidazolium chloride (EMImCl):AlCl3 as an electrolyte. The Al/EMImCl:AlCl3/S@Gf battery exhibited remarkable performance in terms of rate capability and cycle life, delivering a high capacity of 1281 mA h g−1 at a current density of 300 mA g−1 with 90% coulombic efficiency (CE); additionally, it was stable at 800 mA g−1 withdrawing current. By employing an embedding technique to incorporate sulfur particles onto the graphite, we emulated previously observed glitches, such as capacity degradation and poor conductivity resulting in the accumulation of insoluble discharge products hindering ion diffusion. We demonstrated the potential of graphite to enhance the capability of holding sulfur for creating cells with repeatable, stable, and long-lasting charge storage features. This paper elucidates the interactions between carbon, sulfur, and aluminum electrolytes, and sheds light on their respective roles in the fundamental charge-storage process of aluminum–sulfur batteries. [ABSTRACT FROM AUTHOR]

In this paper, a 3D porous polycalix functionalized with a dual Brønsted–Lewis acidic double-charged DABCO-based ionic liquid group (PC4RA@[SiPrDABCO@BuSO3H](FeCl4)) was synthesized using multiple steps, characterized, and then evaluated by spiro formation for catalytic activity. Initially, the polymeric support was modified using the silylation of its hydroxy groups with (3-chloropropyl)-trimethoxysilane as an organo-silane linker to develop PC4RA-SiPrCl. Then, it was post-functionalized using bi-functional acidic IL groups bearing double-charged diazoniabi-cyclo[2.2.2]octane tetrachloro-ferrate(III) with moving active sites of SO3H groups to deliver PC4RA@[SiPrDABCO@BuSO3H](FeCl4). In the next step, the characterization of the designed catalyst was directed by applying FT-IR, EDX, elemental mapping, WPXRD, LPXRD, FE-SEM, STA, and TEM techniques. The catalytic performance of the porous polymeric system was confirmed using the formation of spiro-fused[4H-pyran] as a highly recyclable and stable di-cationic polymer-supported acidic IL under mild conditions. [ABSTRACT FROM AUTHOR]

Inexpensive fabrication with the scalable design of environmentally friendly supercapacitors is highly desirable for portable and wearable electronics. In this context, the role of an electrolyte on two-dimensional (2D) materials such as WS2 nanosheet-based electrodes is important for the rational design of an efficient, stable, and environmentally friendly supercapacitor. In this paper, high-quality and ultrathin 2D WS2 nanosheets are synthesized by an easy, fast, and scalable LiI-assisted liquid phase exfoliation method. The synthesized WS2 nanosheets are then employed as an electrode material in combination with 1-butyl-3-methylimidazolium chloride (BMIC) and polyvinyl alcohol (PVA) gel electrolyte to fabricate a solid-state supercapacitor. The effect of different concentrations of BMIC on the 2D WS2 nanosheet-based electrodes is investigated in a symmetric supercapacitor. An optimum concentration of BMIC in PVA gel provides the best performance due to the low viscosity and high conductivity of the gel electrolyte, resulting from the H bonding alteration inside the PVA matrix. High voltage supercapacitors with a large electrochemically stable window (up to ±4 V), and higher capacitance (5 F g−1) and specific energy density are fabricated using 0.5 M BMIC in the PVA gel electrolyte. The fabricated solid-state devices show 100% specific capacitance retention up to 8000 cyclic charge–discharge cycles. Electrochemical impedance spectroscopy and Kelvin probe force microscopy are employed to investigate the enhanced performance and stability of 0.5 M BMIC in PVA gel electrolyte in combination with a WS2-based electrode. [ABSTRACT FROM AUTHOR]

The utilization and transformation of CO2 under mild conditions, particularly at ambient pressure and moderate temperature, remain challenging and attract widespread attention. Ionic liquids are considered to be green and designable solvents, and have high efficiency for CO2 conversion. Here, a novel aprotic ionic liquid, [Ch][Triz], was discovered as a dual-functional catalyst capable of simultaneously activating CO2 and the substrates, and exhibited outstanding performance in catalyzing the cyclization of CO2 and 2-aminobenzonitriles under solvent-free and mild conditions (such as 0.1 MPa, 30–50 °C), affording a range of quinazoline-2,4(1H,3H)-diones in high yields. Furthermore, [Ch][Triz] IL could be easily recovered and reused up to five recycle runs without obvious activity loss. This work proposes a sustainable approach to CO2 conversion, and holds great potential for quinazoline-2,4(1H,3H)-dione preparation under mild conditions. [ABSTRACT FROM AUTHOR]

One-pot ethanol production, which involves successive biomass pretreatments, enzymatic hydrolysis, and fermentation in a single vessel, is essential for practical bioethanol production. To achieve this, low-toxicity pretreatment solvents such as a zwitterionic liquid, OE2imC3C, are necessary. Although the cellulose-dissolving ability of OE2imC3C has been studied, its biomass pretreatment ability has not been thoroughly investigated. Herein, we investigated the biomass pretreatment ability of OE2imC3C at various temperatures and concentrations. The mildest conditions for successful pretreatment were 75 wt% OE2imC3C at 90 °C. On the other hand, OE2imC3C exhibited a lower pretreatment ability than [C2mim]OAc, which is the best-known cellulose-dissolving ionic liquid. The main reason for the low pretreatment ability of OE2imC3C was its high viscosity. Reducing their viscosity is a key factor for designing zwitterionic liquids with high pretreatment ability. [ABSTRACT FROM AUTHOR]

Considerable interest in designing multi-responsive soft materials for diverse applications is leading to the development of systems that are embedded with functional groups with stimuli-responsive characters. Surface-active ionic liquids (SAILs) with an ability to form various structural aggregates represent an interesting candidate for designing soft materials with stimuli-responsive characters. Embedding photo-responsive moieties into SAILs with existing pH-responsive properties can unlock a broader range of potential uses. Herein, we prepared photo- and pH-responsive catanionic giant vesicles (GVs) through a synergetic interaction between the pH-responsive choline oleate ([Ch][Ol]) and photo-responsive (4-methyl-4-(2-(octyloxy)-2-oxoethyl)) morpholin-4-ium(E)-4-((4-(dimethylamino) phenyl) diazinyl) benzenesulfonate ([C8EMorph][MO]). The photo-responsiveness in the GVs was introduced through [C8EMorph][MO], which shows E–Z isomerisation under 460 nm light irradiation, whereas the pH-responsive character was obtained through [Ch][Ol]. We used absorbance measurements complimented with a computational study to characterize the photo-responsive behaviour. Irradiating the GVs with light of suitable wavelength and changing the pH of the system altered the behaviour of the aggregates. Small-angle neutron scattering (SANS) analysis showed that, before irradiation, the size of the bilayer thickness of the GVs was 28 Å and after irradiation it was increased to 31 Å, leading to an increment in the overall size of the GVs. This was due to the formation of Z-[C8EMorph][MO] after irradiation, which leads to a slight alteration in the interactions between both SAILs. Moreover, the change in pH of the vesicles caused alterations in the size and shape of the vesicles, as confirmed through the SANS analysis. The stability of the GVs in terms of temperature, dilution, and time was analysed to characterise the GVs for practical applications. The insights gained from this study could be valuable for developing materials for these applications such as probes, cargo carriers, and microreactors in future. [ABSTRACT FROM AUTHOR]

The present work involves an improved, pseudo-three-component synthetic approach for the synthesis of dimeric indoles using 4 mol% [BCMIM][Cl] ionic liquid via metal-free synthesis in aqueous ethanol under reflux conditions. A series of 35 derivatives were furnished in up to 95% yields in 0.5 h to 1.5 h. These derivatives were then analyzed using various spectroscopic techniques. The salient features of this methodology are mild reaction conditions, metal-free synthesis, simple work-up procedure, short reaction time, reusability for up to 4 cycles, good to excellent yields and low catalyst loading. The UV-visible and fluorescence spectroscopy techniques were used to investigate the photophysical characteristics of selected derivatives. The absorption and emission spectra reveal a peak wavelength (λmax) in the ranges of 216–228 nm (π–π*), 262–294 nm (n–π*), and 389–407 nm, respectively. A similar trend to the experimental data can be observed in density functional theory (DFT) calculations. The binding affinities of the synthesised derivatives with bovine serum albumin (BSA) and deoxyribonucleic acid (DNA) were computed using AutoDock Vina. Furthermore, 7af, 7ai, 7aj and 7gk were investigated for BSA and DNA binding studies. The ligands exhibited a binding strength of 105 and 103 M−1 with BSA and DNA, respectively. The ethidium bromide (EtBr) displacement assay discloses intercalation as the mode of binding with Ksv values in the order of 102–103 M−1. [ABSTRACT FROM AUTHOR]

Although the preparation of large-area perovskite films using blade-coating technology has made rapid progress in recent years, the instability of precursor solutions and the harmful and toxic solvents limit the preparation of bladed perovskite films in ambient air. In addition, additives are usually indispensable for the preparation of high-quality bladed perovskite films. Here, we introduce the ionic liquid methylammonium acetate (MAAc) instead of N,N-dimethylformamide and dimethyl sulfoxide as a solvent to fabricate perovskite solar cells (PSCs) using the blade-coating method. Using MAAc as a solvent solves the toxic and harmful problems of traditional solvents and realizes the preparation process of bladed perovskite films in ambient air. Surprisingly, the power conversion efficiency of the bladed PSCs prepared under ambient conditions exceeds 14% without additives. Moreover, the unencapsulated device exhibits excellent storage stability in ambient air. This work provides a method for preparing highly efficient and stable perovskite optoelectronic devices using a blade-coating method in ambient air without additives. [ABSTRACT FROM AUTHOR]

A homologous series of 1,2-dimethylimidazolium-based ionic liquids with halide anions are examined by Hirshfeld surface analysis to draw out key structural details of the cation, allowing for a deep understanding of the structure and interactions present within this class of ionic liquids. With respect to cation structures, three distinct alkyl torsion angles are noted when examining the compounds currently reported within the structural database. These alkyl chains account for the largest percentage of cation⋯cation close contacts through a combination of H⋯H and H⋯π interactions. Further, the halide-containing crystals are contrasted with a hydrated form of the compounds, allowing for detailed examination of the changes in non-covalent interactions within the asymmetric unit. It is noted that for the hydrated compound, hydrogen bonding interactions between the water molecule and cation replace the anion⋯cation interactions, accounting, in part, for the lower melting points of these hydrated species. [ABSTRACT FROM AUTHOR]

A novel pyrazole-based catalyst system featuring –CH as a hydrogen bonding donor was developed and utilized for the conversion of CO2 into cyclic carbonates without the use of metals or co-catalysts. It is intriguing that the synthesized pyrazolium ionic liquid ([Bn2DMPz]Br) could efficiently catalyze the coupling reaction of carbon dioxide (CO2) and epoxides at 90 °C, under a pressure of 0.1 MPa CO2, achieving a product yield of up to 99% within just 5 hours. The catalyst can be recycled and reused multiple times without any decrease in its catalytic efficiency. In addition, the pyrazolium ionic liquid was polymerized to get the first pyrazole-based poly(ionic liquid) (PIL). The polymer also exhibits high catalytic activity, excellent stability and easy recyclability. In comparison to other catalysts based on ionic liquids, our catalyst system demonstrates outstanding performance and recyclability at the same time. DFT calculations show that "double-IL" model may easily make the bromide anion serve as a nucleophile and cation [Bn2DMPz]+ serves as a H-donor to stabilize the O− of the epoxide and the carbonate anion with weak interaction. The design strategy based on pyrazole ionic liquid will inspire researchers to develop more catalysts used for CO2 cycloaddition in the future. [ABSTRACT FROM AUTHOR]

In this study, a new bioamphiphile sodium-2-decanamyde-2-methyl propanoate (SDMP) was synthesized to study the photophysical properties of bromelain (BM) in its micellar medium, and the experiment was further extended with the addition of room-temperature ionic liquids (RTILs) and a commonly used anionic surfactant sodium dodecyl sulfate (SDS), salt sodium chloride (NaCl) and a cationic drug nortriptyline (NOT) using steady-state and time-resolved spectroscopy, along with other techniques. For the modulation of the photophysical properties of BM, the interaction of BM was first studied with an SDMP micelle and then with two ILs of different chain lengths, SDS and NOT. This study reveals that micellar assemblies significantly reduce the degradation rate of bromelain owing to partitioning in the palisade layer of micelles from bulk water. The increase in average lifetime with the addition of SDMP after the micellar zone may be the result of hindrance of the excited-state intramolecular proton transfer (ESIPT) process. Furthermore, the stability and activity were compared with those of conventional imidazolium-based ionic liquids, i.e., 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl) and 1-decyl-3-methylimidazolium chloride (C10MeImCl), using spectroscopic techniques. The present study shows that both the studied ILs interact with the functional groups of BM. Therefore, it appears that the SDMP micellar medium stabilizes BM more than an aqueous medium. The interaction between BM and amino acid surfactant (AAS) may provide new insights in the field of green technology using renewable natural resources to create eco-friendly and bio-degradable products. [ABSTRACT FROM AUTHOR]

The formylation of N-methylaniline (1a) with CO2 and ammonia borane, NH3·BH3 (AB) produced selectively N-methyl-N-phenylformamide (3a) in the presence of the halide imidazolium salts ([IL]X). In contrast, a mixture of two products, formylated 3a and methylated 2a (N,N-dimethylaniline), was obtained in the presence of non-halide imidazolium salts, containing BF4−, PF6− or OS (octyl sulfate) anions. Reactions of other primary and secondary amines with AB and CO2 carried out in the presence of halide salt, [dbim]Cl (dbim = 1,3-dibutyl imidazolium cation) selectively lead to the formation of formamides as the only products. The effect of ionic liquids on the selectivity of amine formylation was explained by their ability to stabilize different forms of boron formates. In the presence of halide salts, the reaction of AB with CO2 results in the formation of BH(OCHO)2 which is responsible for the formylation of amines to formamides. In contrast, the formation of a mixture of boron formates, BHn(OCHO)3−n (n = 1, 2), in the presence of non-halogenated imidazolium salts results in the production of a mixture of formylated and methylated amine derivatives. [ABSTRACT FROM AUTHOR]

Copper, iron–chloride ionic liquids (ILs) were immobilized on SBA-15 via N-methylimidazole grafting with C–Cl in chloropropylsilane pre-anchored on SBA-15, followed by FeCl3 and CuCl2 coordination to imidazolium chloride to generate a double metal IL-supported mesoporous composite (SIL-CuFe). The prepared composite exhibited an effective catalytic performance for the solvent-free oxidation of styrene to benzaldehdye (BzH) with H2O2 oxidant, offering 51% conversion, a turnover number (TON) of 330.5 mol molFe+Cu−1, and a selectivity of 71% at a reaction temperature of 70 °C. The composite catalyst can be easily recovered and effectively reused without a significant loss in activity and selectivity. The quenching experiments by adding tert-butanol (TBA), 1,4-benzoquinone (p-BQ) and L -histidine (L -HIS) in the reaction system were conducted to identify the type of reactive O species, specifically ˙OH, ˙O2−, and 1O2, produced by catalyst activation with H2O2 and played a main role in the oxidation. The reaction mechanism of the oxidation process is also proposed. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to energy chemicals in aqueous electrolytes is usually limited by logy OER at the anode and competing HER at the cathode. An N-doped carbon encapsulated Cu-CoO composite (CuCo@NC) fabricated by the facile pyrolysis of Cu and Co salts and melamine mixture was used as a cathode for CO2 reduction to CO and CH4, coupled with the anodic oxidation of CH3OH to dimethoxymethane in an ionic liquid-methanol medium to boost the anode reaction. The electrolytic system exhibits efficient redox activity with a higher average FEDMM (58.7%) within 48 h and high instantaneous FEC1 (99.1%) for CO + CH4 at 24 h. Simultaneous production of the high-value chemicals DMM and CO + CH4 in an electrolysis cell is achieved. The surface composition and structure of this composite with higher saturation magnetization, specifically the contribution of the Cu, CuOx, and CoOx crystallines to the catalytic performance of CO2eRR and magnetic properties, were explored. The catalytic system achieves high activity within 72 h of continuous electrolysis, and the electrode and ionic liquid can remain intact after being used three times, indicating the high operational stability of the CO2eRR system. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) absorption has attracted much attention due to serious environmental pollution caused by ammonia in recent years. In this paper, the solubilities of ammonia (pressure–temperature–composition (pTx) data) in five dialkylphosphate-based ionic liquids (ILs) were determined at different temperatures (303.15 K–333.15 K) and pressures (about 0.1 MPa–0.6 MPa). It was found that the solubilities of ammonia increased with decreasing temperature and increasing pressure. NH3 dissolution could be improved in ILs with longer side chain lengths in the imidazolium ring of cations and shorter side chain lengths in anions, which could be related to the densities and viscosities of the ILs. Moreover, based on NH3 solubility data, Henry's law constants were obtained using the Peng–Robinson (PR) equation of state. Consequently thermodynamic properties including solution enthalpy ΔsolH, solution entropy ΔsolS and solution Gibbs free energy ΔsolG were calculated. The results indicated that higher absolute values of ΔsolH could generally demonstrate stronger interactions between NH3 and ILs, which corresponds to the smaller Henry's law constants and higher solubility of NH3 in the ILs. In addition these ILs can exhibit excellent reversibility, indicating that these ILs can be regarded as potential absorbents for NH3 in chemical industry processes. [ABSTRACT FROM AUTHOR]

Ionic liquids have excellent physical and chemical properties, enabling them to be widely used in electrochemical oxygen sensors. In recent years, the preparation of modified materials and ionic liquids mixed to improve the oxygen sensitivity of sensors has become a hotspot. In this study, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), which is a liquid at room temperature, was successfully prepared by a simple one-pot method, and BMIMPF6 reacts at different oxygen concentrations. Bamboo-like carbon nanotube (BCNT) composites containing cobalt nanoparticles derived from graphite phase carbon nitride (g-C3N4) were prepared and fully mixed with the ionic liquid to form the BCNT/Co + BMIMPF6 composite. The electrochemical behavior of oxygen in the electrochemical sensor was studied. The results show that the response current and stability of the oxygen sensor based on the BCNT/Co + BMIMPF6 composite are significantly improved, the sensitivity is 1.15 μA/[%O2], the response time is 16 s, and the linearity is good. [ABSTRACT FROM AUTHOR]

Magnetic ionic liquids (MILs) form a subclass of ionic liquids (ILs) that possess paramagnetic properties and can respond to an external magnetic field, facilitating ease of manipulation in immiscible solvents. Despite being popular as solvents in catalysis, organic synthesis, and separations, MILs are obtained through complex and labor-intensive synthetic/purification routes that increase cost, are time-consuming, and require expertise in organic synthesis. To date, no study has successfully developed a straightforward and rapid procedure for MILs that also eliminates purification. In this study, transition metal-containing bis[(trifluoromethyl)sulfonyl]imide ([NTf2−]) salts and N-alkylimidazoles, diglycolamides, and O-donor ligands were used to produce hydrophobic MILs that could maintain their chemical integrity under water for over 6 months. A neat heat/stir method was employed to form MILs for long-term storage or later use while an in situ method was used for select combinations to generate the same MIL under 30 s in the bulk presence of water. Viscosities as low as 198.3 cP at 22.8 °C were obtained that were comparable to previous classes of paramagnetic solvents. In contrast to MILs comprised of O-donor ligands, those formed with alkylimidazoles and diglycolamides were found to be soluble in non-polar solvents such as hexane at concentrations of up to 50% (w/v) MIL-to-solvent ratio while being insoluble in water even at 0.01% (w/v). Effective magnetic moment values for MILs ranged from 2.78 to 5.16 Bohr magnetons (μB) and were observed to be dependent on the metal center in the [NTf2−] salts. The solvents possessed excellent thermal stabilities with diglycolamide-based MILs exhibiting structural resilience up to 345 °C. The synthetic design of these MILs has successfully achieved the primary objective of facilitating easy access to magnetoactive solvents by reducing their preparation to a simple step consisting of mixing two readily available reagents to expedite production in high-throughput laboratories where these compounds can be incorporated in automated separations and analytical testing systems where their magnetic properties can be conveniently exploited. [ABSTRACT FROM AUTHOR]

Lithium isotopes with high abundances (6Li and 7Li) are crucial for the advancement of nuclear energy. In order to achieve the effective separation of 7Li, a Sudan I-[HMIm][BF4]-anisole extraction system was built employing Sudan I (1-benzeneazo-2-naphthol) as the extractant and hydrophobic ionic liquid [HMIm][BF4] as the co-extractant. By optimizing the organic and aqueous phase components, the extraction rate of the system could reach up to 26.30%, and the single-stage separation factor of the system could reach 1.015 ± 0.001. Meanwhile, the mechanism of the extraction process was investigated, and it was found that the ratio of Sudan I to lithium ions is 1 : 1, and the thermodynamic enthalpy change of the extraction process was less than zero (ΔH < 0), indicating that the extraction process of the system was an exothermic process. The construction of the Sudan-ionic liquid extraction separation system provides a new idea for the study of 7Li enrichment and separation and also provides a possibility for the industrialization of high-abundance 7Li enrichment. [ABSTRACT FROM AUTHOR]

Ionic liquids, which are widely known as room temperature molten salts, have been the subject of much scientific debate for more than a decade. These compounds can be used as green solvents or even as additives in many reactions. Due to their noticeable conductivity, which is a function of the interaction energies existing between the ion pairs in ionic liquids, the synthesis and introduction of new families of these chemicals are of importance. The target of this paper is to design new carboxylate-based ionic liquids containing OH and CF3 groups. Our results indicate that the properties of these ILs are highly affected by the presence of OH and CF3 groups, in which OH stabilizes the negative charge of the anion via intramolecular hydrogen bonds and CF3 stabilizes it through the electron withdrawing effect. These groups decrease the binding energy between the anion and cation of the carboxylate-based ionic liquids and thus affect their physical properties such as melting point and density as well as their chemical properties. All calculations in this study were performed in the gas phase at the B3LYP/6-311++G(d,p) level. [ABSTRACT FROM AUTHOR]

This paper reports the NH3 solubilities and absorption mechanisms in the imidazolium- and ammonium-based ionic liquids. The cations were 1-methyl-3-(4-sulfobutyl)-imidazolium, 1-(2-hydroxyethyl)-3-methylimidazolium, 1-ethyl-3-methyl-imidazolium, N-carboxymethyl-N,N,N-trimethylammonium, N-(2-hydroxyethyl)-N,N,N-trimethylammonium, and N-butyl-N,N,N-trimethylammonium, whereas the anions were bis(trifluoromethanelsulfonyl)amide, tris(pentafluoroethyl)trifluorophosphate, trifluoromethylsulfonate, and hydrogensulfate. The Brønsted acidic ionic liquids, consisting of sulfo and carboxy groups and hydrogensulfate anion, absorbed larger amounts of NH3, followed by the hydroxy-functionalized and nonfunctionalized ionic liquids. The NMR and Raman spectra indicated that the Brønsted acidic ionic liquids absorbed NH3 as both the molecular ammonia (physical absorption) and the ammonium cation (chemical absorption). Although the hydroxy group strongly interacted with NH3, the hydroxy-functionalized ionic liquids dissolved NH3 only physically, similar to the nonfunctionalized ionic liquids. In conclusion, the chemical absorption brought about the higher NH3 solubilities in the Brønsted acidic imidazolium- and ammonium-based ionic liquids. [ABSTRACT FROM AUTHOR]

Six dual active site ionic liquid catalysts were prepared by using triethylenediamine-grafted 1-bromotetradecane as a cation and coordinating with different organic anions. The structures and properties of the catalysts were characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis (TGA). The synthesis of poly(isosorbide carbonates) (PICs) via the transesterification polycondensation of dimethyl carbonate (DMC) and isosorbide (ISB) catalyzed by a cation and anion was studied. A single factor experiment was used to investigate optimal process parameters. FT-IR, NMR, TGA, and differential scanning calorimetry (DSC) were adopted to characterize the structures and properties of PICs. The results showed that under the same process parameters, the catalyst using imidazole as an anion had the best catalytic performance. Under optimal process conditions, the conversion of ISB reached 98.82%, the weight average molecular weight of the PIC reached 28 840 g mol−1, and the glass transition temperature (Tg) of the PIC was 149 °C. [ABSTRACT FROM AUTHOR]

Three novel redox ionic liquids (RILs) based on carbazole, incorporating imidazolium and bistriflimide (TFSI) groups, have been successfully synthesized and their electrochemical properties comprehensively evaluated. These compounds synergize the exceptional charge transport characteristics of carbazole with the appealing physical and electrochemical attributes of ionic liquids. In this study, we investigated the electron transfer and mass transfer behaviors of these RILs through cyclic voltammetry, comparing the results with those predicted by the Marcus theory, which exhibited a favorable agreement. Notably, we employed the asymmetric Marcus–Hush (AMH) model and the Compton approach to delve into the parameters influencing electron transfer dynamics. The examined RILs, characterized by their asymmetrically positioned redox centers, manifest a heterogeneous rate constant primarily influenced by the size of the redox-active moiety rather than the solvated radius of the entire molecule. Consequently, these redox-active species favorably orient themselves towards the electrode surface, resulting in higher kinetic constants than initially envisaged by the conventional theory. This insightful understanding bears significant importance in the development of efficient carbazole-derived technologies with tunable features. [ABSTRACT FROM AUTHOR]

The present work describes the synthesis of a material consisting of a bisimidazolium ionic liquid supported on graphene oxide. The prepared nanocomposite was characterized by different physicochemical techniques such as FT-IR, XRD, CHN, SEM, TEM and EDAX. The synthesized nanocomposite was further utilized as an effective heterogeneous catalyst for the synthesis of tetraketone derivatives, which are biologically significant, using dimedone and aryl aldehydes as the substrates at 50 °C and a green solvent. One of the tetraketone products has been confirmed by single crystal XRD. The catalyst displayed high reaction yields, facile separation, short reaction time, good stability and recoverability up to six consecutive reaction rounds with no discernible loss in its catalytic activity. [ABSTRACT FROM AUTHOR]

In order to extend the use of supported ionic liquids as effective heterogeneous catalysts, in this research, a novel FSM-16 supported Brønsted acidic ionic liquid (FSM-16-IL-SO3H) was synthesized and characterized using various techniques such as FT-IR, TGA, SEM, EDX, XRD, and BET. The prepared catalyst was used as a new, environmentally friendly, and recyclable catalyst for the synthesis of biscoumarin derivatives through the reaction of aromatic aldehydes and 4-hydroxycoumarin with short reaction times and high yields. [ABSTRACT FROM AUTHOR]

Herein, a pyridinium-based ionic liquid-functionalized porphyrin (PBILFPc) photocatalyst was successfully synthesized and characterized using various techniques, such as 1H NMR, HR-MS, FT-IR, SEM, and XPS. The surface area of the photocatalyst was calculated using the BET method and found to be 125.882 m2 g−1. The successful formation of the porphyrin was supported by the extremely shielded inner NH-protons at −2.61 δ ppm. The energy band gap and Hammett acidity were determined to be 1.42 eV and 0.64, respectively, using UV-Vis spectroscopy. Subsequently, PBILFPc was employed as a proficient photocatalyst for the arylation of various N-heterocycles with inactivated/activated aryl halides. The photocatalytic cross-coupling was achieved under metal/base/ligand-free conditions in a laboratory-made photoreactor under the exposure of 5 W white LED light and ambient conditions. Similarly, this protocol was also appropriate for a variety of N-heterocycles, offering N-substituted aryl/alkyl derivatives in appreciable yields (71% to 91%). The photocatalytic activity of PBILFPc was supported by its low energy band gap, promoting the absorption of radiation in the visible region and leading to the formation of excitons (holes and electrons). Moreover, the presence of Brønsted acidic groups together with excitons enhanced its photocatalytic activity at room temperature. This protocol afforded the synthesis of moieties analogous to clotrimazole using the optimized parameters. Furthermore, after the reaction, the reused PBILFPc photocatalyst was found to be active and afforded a reasonable yield (82%) even after six runs. Thus, this sustainable metal/base/ligand-free PBILFPc photocatalytic route in a homemade photoreactor under visible light will motivate investigators to study the synthesis of medicinally vital scaffolds and other intermediates. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) provides an essential nitrogen source for the entire ecosystem. It is also a critical raw material for industrial production and human survival. NH3 emissions during various utilization processes will result in serious environmental problems and waste of valuable sources. Green solvents like ionic liquids (ILs) and deep eutectic solvents (DESs) appear as potential materials for gas capture due to their tunable properties. This review systematically summarizes their utilization of NH3 absorption and separation. The main contents include ILs (conventional ILs, hydroxyl-functionalized ILs, protic ILs, metallic ILs, multiple ILs, polyionic ILs, and IL-supported materials) and DES materials (common DESs, hydroxyl-functionalized DESs, protic DESs, multiple-sites DESs, metallic DESs, and DES-supported materials). The influence of components in the green solvents on their physical property, absorption mechanism, and absorption and separation performance are systematically discussed. The future investigation direction and prospects are also discussed on the basis of analysis of present green solvents. This review is helpful for researchers to gain an overall understanding of ILs and DESs for NH3 capture. [ABSTRACT FROM AUTHOR]

In this paper, the ionic liquid (IL), 1-octyl-3-methylimidazolium hexafluorophosphate ([Omim][PF6]), was employed to synthesize β-cyclodextrin (β-CD)-functionalized carbon nanotubes/TiO2 (IL–CD-CNTs/TiO2) nanocomposite via a one-pot solvothermal process. The as-prepared product was characterized by SEM, TEM, XRD, TG, FT-IR, EIS, and so forth. Coupled with an aspirated in-syringe device, IL–CD-CNTs/TiO2 could yield the rapid removal of water contaminants within 8 min. In addition to the excellent adsorption capacity, this dual-functional photocatalyst also showed enhanced photocatalytic activity under visible light at a degradation rate of 97% within 180 min. The photocatalytic mechanism based on the formation of the inclusion complex, density functional theory, and electronic structure of IL–CD-CNTs/TiO2 was comprehensively discussed. The IL not only served as the reaction medium but also played a crucial role in improving the adsorption capacity and photocatalytic activity. By exhibiting a strong electron-donating character, IL could promote efficient charge transfer, inhibiting the recombination of photogenerated electron–hole pairs. The as-prepared photocatalyst―capable of rapid adsorption and photodegradation―can meet the requirements of practical applications and reveals a promising direction toward wastewater treatment. [ABSTRACT FROM AUTHOR]

Four different acidic and basic ionic liquid intermediates were prepared first, and then combined with designed Fe–molybdenum Keggin-type heteropolyacids to prepare four functionalised heteropolyacid ionic liquid catalysts, functionalised heteropolyacid ionic liquids (FPOM-Ils). The performance of the catalytic degradation of bottle-grade polyester using the four heteropolyacid ionic liquids was investigated by taking waste mineral water bottle fragments as samples. Orthogonal tests were designed to rank reaction conditions in terms of their effects on the catalytic performance, which was most significantly affected by the reaction temperature. The degradation product, bis(hydroxyethyl) terephthalate (BHET), was also analysed for its chemical structure and purity. The results showed that the four heteropolyacid ionic liquid catalysts were successfully prepared, with good thermal stability. Among them, [HO3S-(CH2)3-mim]6[Fe(H2O)FeMo11O39] showed the best catalytic performance, which was achieved at 196 °C, a feeding ratio of 8 : 1, a reaction time of 3 h, and a catalyst dosage (as a percentage of reactant mass) of 0.2 wt%. At 196 °C, the alcoholysis rate could reach 100% and the yield of BHET was 91.92%. After six times of recycling, the alcoholysis rate was still as high as 94.36% and the yield of BHET was 82.3%, which demonstrated the desirable performance and promising development prospects of the prepared heteropolyacid ionic liquid catalysts in the catalytic degradation of bottle-grade polyester. [ABSTRACT FROM AUTHOR]

Lignin is the largest renewable source of aromatic compounds, creating an opportunity for the chemical industry as a feedstock provided that the deconstruction and upgrading methods become economically feasible. Lignin valorization is performed using superoxide radicals (˙O2−) as an oxidizing reagent, which are electro-generated in situ through the oxygen reduction reaction (ORR) in an aprotic ionic liquid [BMIM]BF4. In this study, both the current efficiency and the percent conversion of lignin valorization are improved by simply reducing the viscosity of the electrolyte. The electrochemical analysis and molecular dynamics (MD) simulation results indicate that the presence of non-proton organic solvent CH3CN in [BMIM]BF4 can significantly improve the mass transfer process of O2, thereby accelerating the generation rate of ˙O2−. It is verified using p-benzylethoxyphenol (PBP) as a lignin model compound with a higher Faraday efficiency of 35.3% in [BMIM]BF4/CH3CN (7 : 3 v/v) than that of 15.5% in pure [BMIM]BF4. Finally, an actual lignin sample in [BMIM]BF4/CH3CN exhibited a percent conversion of 50.3% to selectively obtain only 4 kinds of the main small molecule aromatic compounds. [ABSTRACT FROM AUTHOR]

The green synthesis of sulfur-containing compounds via the use of CO2 as a C1 feedstock to build C–S bonds is an attractive topic. Although a few implementations for this route have been reported, the transformation of CO2 at ambient conditions remains a great challenge. In this work, a novel benoxazolone-based ionic liquid (i.e., tetrabutylphosphonium benoxazolone, [P4444][Benoxa]) was discovered, which could efficiently catalyze the synthesis of benzothiazoles via the cyclization of 2-aminothiophenols with CO2 in the presence of hydrosilanes at atmospheric pressure and room temperature (e.g., 30 °C, 0.1 MPa). The catalytic protocol was applicable to various 2-aminothiophenols bearing electron-withdrawing or electron-donating substituents, affording the corresponding benzothiazoles in good-to-excellent yields. To the best of our knowledge, this is the first example of the synthesis of benzothiazoles using CO2 under solvent-free and ambient conditions. [ABSTRACT FROM AUTHOR]

A series of dicationic ionic liquids (DcILs) (1–5), with varying lengths of alkyl chain along with [FeCl3Br]− as the counter anion, have been synthesized and are characterized by using FT-IR, Raman spectroscopy, and mass spectrometry besides single crystal X-ray analysis. The thermal stability, chemical and elemental composition of the synthesized compounds are assessed by thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) respectively. They have been exploited as extractants and catalysts for oxidative desulfurization (ODS) of liquid fuels using H2O2 as an oxidizing agent. Certain parameters like the effects of reaction time, temperature, catalyst loading amount, oxidant-to-sulfur ratio, and reactivity of different sulfur substrates on desulfurization have also been surveyed comprehensively. The synthesized DcILs exhibit very efficient extractive and catalytic activity with the advantage of very mild reaction conditions, rapid reaction equilibrium, and substantial sulfur removal at room temperature with minimal amount of catalyst and oxidant. A reaction mechanism of DcILs with DBT has been proposed and its kinetics appeared to be a pseudo-first-order reaction. The extraction and catalytic oxidation (ECODS) process has been explicated and authenticated by GC-MS. The present work demonstrates that DcILs have the least contribution to the contamination of liquid fuels as they are insoluble in them and due to higher recyclability, they may be attributed as green and eco-friendly extractants as well as catalysts. [ABSTRACT FROM AUTHOR]

Systemic acquired resistance (SAR) is one of the most promising ways to support plants in the fight against viruses. Using this approach biological or chemical factors interact with plants and stimulate their immune system against infections before infection occurs. This paper presents synthesis, physical properties, phytotoxicity and SAR induction efficacy of 15 ionic liquids, derivatives of SAR inducers paired with the cholinium cation, an essential nutrient for organisms. SAR induction efficacy tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by tobacco mosaic virus (TMV). [ABSTRACT FROM AUTHOR]

Temperature dependent (T = 298–450 K) molecular dynamics simulations were carried out with the ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), in order to explore the validity of the Onsager–Glarum (OG) relationship, for dipolar liquids with τM andτD being respectively the molecular rotation and the dielectric relaxation times. The presence of strong molecular correlations and the inherent spatiotemporal heterogeneity in [BMIM][PF6] is expected to severely limit the validity of the OG relationship which is based on the continuum model point dipole description of dipolar liquids. We explored this aspect via simulations of the rank () dependent collective single particle reorientational correlation functions (C(t)), the structural hydrogen bond fluctuation dynamics (CHB(t)), and the medium viscosity (η). The simulated average single particle reorientational correlation time (τ) was used as a bridge between τM and τD in order to explore the validity of the OG relationship in [BMIM][PF6]. The coupling between the simulated 〈τ〉 and simulated η was then followed to reflect the medium heterogeneity. Simulated CHB(t) showed strongly stretched exponential relaxations with β (stretching exponent) ∼0.2–0.5. The ratio between 〈τ=1〉 and 〈τ=2〉 showed significant deviation from the Debye (+ 1) law. The simulated Kirkwood g factor, being significantly less than unity, indicated strong orientational correlations among the molecular ions. Estimated hydrodynamic effective volumes, (Veff), from 〈τ〉 were found to be considerably smaller than the molecular volume of the cation, indicating either small amplitude rotation of the dipolar ion or a non-Brownian move such as angular jumps. [ABSTRACT FROM AUTHOR]

Novel sulfonated phenylamine ionic liquids were prepared through a simple ring-opening reaction of phenylamine with 1,3-propanesulfonate (PS) and evaluated as catalysts for the esterification of trimethylolpropane and acrylic acid to produce trimethylolpropane acrylate. By adjusting the molar ratio of PS to phenylamine, sulfonated phenylamine (PSn-PA) with different PS group numbers (n = 1, 2, 3) can be obtained. Among them, PS3-PA possessed the strongest acidity and presented the best trimethylolpropane conversion (100%) and TMPTA selectivity (85.4%) under mild reaction conditions. The results showed that the catalytic performances of PSn-PA were closely related to their acidic strength. A possible mechanism for the enhanced catalytic activity in the presence of these novel sulfonated phenylamine ILs had been proposed. Moreover, an obvious phase-separation phenomenon, in which the catalyst completely dissolved in a reaction system, but precipitated at the end of reaction, was observed during the reaction process. This work provided an efficient and simple approach for the design of new ionic liquids with multiple acidic sites. This kind of acidic catalyst with phase separation behavior and high performance has potential to be used in more acid-catalyzed reactions, especially for polycarboxylic acid or polyol systems. [ABSTRACT FROM AUTHOR]

Biocompatible cholinium-based ionic liquids (ILs) are used extensively in the pharmaceutical and biomedical industries. To enhance structural stability and solubility of drugs, as well as their controlled delivery, IL-based active pharmaceutical ingredients (API) are used widely. In this study, we selected two different sets of biodegradable ILs which also have a direct influence on the structure and stability of insulin. Moreover, we used DFT-based electronic structure calculations with molecular dynamics (MD) simulations to study the effect of a mixture of two different anions in the IL medium and the role of water molecules on the stability of insulin. Microhydration and molecular-level DFT calculations suggest that ILs based on choline geranate [Cho][Ger] and choline taurine [Cho][Tau] differ in their hydration patterns, and thus the stability of the clusters varies significantly. This finding is important for exploring the role of water molecules within these mixtures (i.e., on the interactions between [Ger] and [Tau]). From our calculations it is found that the [Cho][Ger] IL stabilizes the insulin dimer structure strongly through water-mediated H-bonding interactions, whereas the [Cho][Ger][Tau] ternary complex destabilizes insulin. This indicates that IL mixtures over a wide range of concentrations and water molecules at the interface may influence the structural stability and enable suitable combinations of oral formulations to be predicted for drug-delivery applications. From the MD simulations, we conclude that [Cho][Ger] stabilizes the insulin dimer. Our combined DFT and MD simulations will provide valuable information for experimentalists to design and develop novel oral insulin formulations. [ABSTRACT FROM AUTHOR]

Self-buffering and biocompatible ionic liquids (ILs) derived from biological buffers, such as Good's buffers, have been recognized as potential innovative green agents for many practical applications. In order to develop their processing technologies, the thermophysical properties and molecular interactions of the binary systems containing tetramethylammonium 4-(2-hydroxyethyl)-1-piperazinepropanesulfonate ([TMA][EPPS]) with water, methanol or ethanol were investigated in this work. The densities and viscosities of the binary systems were measured at temperatures from 283.15 K to 333.15 K and concentrations from 0.342 mol kg−1 to 2.048 mol kg−1 under atmospheric pressure. The thermal expansion coefficients, the apparent molar volumes, and the solubilities of [TMA][EPPS] in water, methanol or ethanol at 298.15 K were also estimated from the experimental results of density measurements. The viscosity data of the ionic liquid solutions were correlated accurately with the Vogel–Fulcher–Tammann (VFT) equation. Moreover, the dissociation process and the solvation behavior of [TMA][EPPS] and its constituent ions in water, methanol, and ethanol were studied by using the COSMO-RS-based quantum calculations. The molecular interactions of the TMA cation, EPPS anion, or [TMA][EPPS] with solvent molecules (water, methanol, and ethanol) were also studied using DFT calculations. As a result, this IL derived from biological buffer has the ability to dissolve in water and organic solvents such as methanol and ethanol. This implies that these kinds of ILs are expected to have wide applications, not only in aqueous solution but also in organic solvent mixtures. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have shown great catalytic effects in the conversion of fructose to 5-hydroxymethylfurfural (HMF) but the dehydration mechanism remains ambiguous. In this work, density functional theory (DFT) calculations have been carried out for the mechanism of the dehydration of fructose to HMF, catalyzed by functionalized ILs. ILs with different kinds of functionalized imidazolium-based cations and SO3 group-based anions have been used to investigate the catalytic effects of different anions and cations on the dehydration of fructose. The whole reaction process of fructose to HMF includes three dehydration steps. The overall rate-determining step is the second dehydration, and the functionalized cations showed good proton transfer ability to catalyze the reaction in the dehydration steps. The proton shuttling ability of cations is better than that of anions. The anions can form strong H-bonds with the fructose and cations and provide a polar environment to stabilize intermediates and transition states. The high catalytic activity is attributed to the synergetic catalysis of cations and anions to complete the dehydration of fructose. The dehydration reaction mechanism from fructose to HMF catalyzed by [BmimHSO3][HSO4]-functionalized ILs has been proposed by DFT calculations. This study emphasizes the catalytic performance of functionalized ILs replaced by different substituent groups and the dehydration mechanism of fructose to HMF. [ABSTRACT FROM AUTHOR]

Protic ionic liquids (PILs) have been the focus of research both domestically and internationally because PILs have demonstrated improved NH3 separation capabilities and have been applied to separate NH3 from industrial tail gas. As the stabilities of PILs are overestimated, it is important to study their long-term stability as well as the degradation mechanism of PILs to slow down their degradation and improve their long-term stability. In this work, degradation experiments on 7 PILs were carried out at up to 120 °C for 600 h in N2 and O2 atmospheres. The impacts of different anions, cations, and NH3 contents on the degradation processes of PILs were explored. High-performance liquid chromatography (HPLC) was used to quantify the degradation ratios of the PILs. The degradation products of PILs were identified and quantified via gas chromatography (GC)/mass spectrometry (MS), and the degradation mechanisms of the PILs were extrapolated according to the degradation products. Our results revealed that degradation occurred mainly in the cations, although the anions also affected the degradation processes of the PILs. The degradation ratios of the PILs decreased with an increase in the NH3 content. This study on the degradation processes of PILs provides theoretical support for the industrial applications of PILs in NH3 separation. [ABSTRACT FROM AUTHOR]

The decrease in the effectiveness of current treatments for hair dermatosis caused by the resistance to antifungals affects patients, causing many cases of recurrence. Thus, the search for low-cost materials with potential antifungal and antibiofilm effects that are easy to prepare, water-soluble, polydisperse and chemically green is significant. Thus, the purpose of this research is to develop mini-emulsions based on protic ionic liquids and oleic acid that present antibiofilm activity against strains related to animal hair dermatophytosis. The effects of three different protic ionic liquids (PILs), 2-hydroxy diethylammonium lactate (2-HDEALa), 2-hydroxy diethylammonium salicylate (2-HDEASa) and 2-hydroxy diethylammonium maleate (2-HDEAMa), on the size, stability and antibiofilm activity of the mini-emulsions were investigated. The effects of PILs and oleic acid concentrations on the size, polydispersity and electrostatic stability of mini-emulsions were evaluated using dynamic light scattering and electrophoretic light scattering. The raw materials and mini-emulsions were also characterized using nuclear magnetic resonance (NMR) spectroscopy and fluorescence experiments including confocal microscopy. In addition, the potential of the synthesized nanomaterials to eradicate Microsporum canis biofilms on animal hair was evaluated. As a result, it was observed that mini-emulsions with smaller sizes, a lower polydispersity index and high electrostatic stability were produced with 10 mM oleic acid and 20 mM 2-HDEALa, 50 mM 2-HDEAMa and 50 mM 2-HDEAMa using a simple and low-cost synthetic method. Furthermore, the confocal microphotographs demonstrated that the mini-emulsions had a spherical shape and the fluorescence and NMR analyses showed that the PILs 2-HDEALa and 2-HDEAMa efficiently covered the oleic acid in the mini-emulsions. Regarding the treatment of dermatophytosis in animal hair using mini-emulsions, it was found that these nanomaterials eliminated 100% of the M. canis biofilm. In conclusion, chemically green molecules such as the PILs 2-HDEALa, 2-HDEAMa and 2-HDEASa were able to form mini-emulsions easily and inexpensively with oleic acid. The PILs presented a synergetic effect with oleic acid, providing the complete eradication of the M. canis biofilm. Therefore, the results of this study suggest that these nanomaterials could be a potential water-soluble formulation to be used as a lotion in the treatment of animal hair dermatoses. [ABSTRACT FROM AUTHOR]

In this paper, we have demonstrated the facile synthesis of stable gold nanoparticles (AuNPs) using imidazolium ionic liquids (ImILs) as a stabilizer as well as a surfactant and their surface plasmon resonance (SPR) in different molecular solvents with varying dielectric properties. The preparation of AuNPs capped with N,N′-dialkyl ImILs of different chain lengths (denoted as [C4,Cn-im]Br, n = carbon number of the alkyl chain) has been investigated. With one long alkyl chain (n≥ 14), these AuNPs could be stably dispersed in solution over a month. The amphiphilic nature of the imidazolium salt dictates the stability and dispersion of these AuNPs in organic or aqueous solvents. Alkyl chain lengths (n≥ 14) and the amount of ImILs have insignificant effect on the size of AuNPs and they possess an average size of 5 nm. These ionic liquid stabilized AuNPs were exploited to examine their optical properties when exposed to various solvent systems by measuring the change in the SPR spectrum. It was seen that the position of the SPR band of AuNPs is greatly influenced by the solvents under consideration. The shift in the SPR absorption band is observed to be in the range of 520 nm to 605 nm for AuNP@[C4,C16-im]Br from nonpolar to highly polar solvents. The considerable discovery presented here is that the λSPR of the SPR shifts to the blue with the increase of carbon atom in the alcohol chain from methanol to 1-decanol. Also for polyethylene glycols (PEGs), the λSPR shifts to the blue with the increase in molecular weight from PEG 200 to PEG 600. In above both cases, the variation in SPR of AuNPs is observed according to the dielectric properties of the medium in addition to the steric factor of alcohols and PEGs during their interaction with AuNP surfaces. [ABSTRACT FROM AUTHOR]

In the process of recovering platinum group metals by extraction, separation of Pt and Ir is very difficult because Pt(iv) and Ir(iv) show similar chemical properties and extraction behaviours in hydrochloric acid medium. In this paper, a betaine-based ionic liquid [C6bet]Br was firstly applied to the separation of Pt(iv) and Ir(iv). [C6bet]Br showed remarkable precipitation performance of Pt(iv) and Ir(iv). The impactful extraction was realized by importing [C6mim][NTF2] as the hydrophobic phase with extraction efficiencies of ca. 99% and 88% under optimal conditions. A selective reduction process for Ir(iv) was firstly proposed for the separation of these two similar PGMs by using hydroxylamine hydrochloride (NH2OH·HCl). The mechanism of extracting Pt(iv)/Ir(iv) using [C6bet]Br was confirmed to be an anion-exchange process by spectroscopic analysis (UV-Vis, FT-IR, 1H NMR) and the method of continuous variation. The electrostatic potential map of [C6bet]Br was calculated for the first time to confirm the anion-exchange mechanism. 8 M HCl was effective for the back extraction of Pt(iv) and Ir(iv). [ABSTRACT FROM AUTHOR]

In this paper, tris(hydroxymethyl)methylene ammonium acetate supported on GO as a new multifunctional heterogeneous catalyst was synthesized. After its characterization by different techniques such as FT-IR, TEM, FESEM, EDS, XPS, solid-state MAS NMR and elemental analysis, it was used as an efficient catalyst for the synthesis of hexahydroquinolines (HHQs) via a one-pot multi-component reaction. Different HHQs were synthesized in the presence of this heterogeneous metal-free catalyst in good to high yields at room temperature under solvent-free conditions. The catalyst was easily separated and reused at least five times without significant loss of activity. The acidic nature of GO improved the catalytic activity of the supported ILs and also provided heterogeneity to the ILs. This is the first report for the synthesis of HHQs in the presence of a multifunctional heterogeneous catalyst. [ABSTRACT FROM AUTHOR]

A series of reusable polystyrene-supported imidazolium acidic ionic liquid catalysts were synthesized to replace industrial sulfuric acid for the synthesis of bisphenol compounds. These ionic liquids were covalently bonded to the support, reaching a high loading of 1.62–1.80 mmol g−1, respectively. As expected, they achieved a catalytic effect comparable to that of sulfuric acid in the condensation reaction of 9-fluorenone with phenol. Under the optimum reaction parameters, a high yield and high selectivity of 99.9% and 99.7% were achieved for 9,9-bis(4-hydroxyphenyl)fluorene (BHPF). Moreover, this catalyst was also employed for synthesizing other bisphenol compounds and 99.0% conversion of the substrate was achieved. Based on the experimental results and density functional theory (DFT) calculations, a possible reaction mechanism was proposed, which indicated that 9-fluorenone and phenol were simultaneously activated through the synergistic catalysis of anions and cations in a polystyrene-supported ionic liquid catalyst. The recycling experiment results suggested that [PS-PsIm][CF3SO3] maintained a high catalytic activity in five reaction runs, making this a promising catalyst for the synthesis of bisphenol compounds. [ABSTRACT FROM AUTHOR]

The voltage-induced microstructure of 1-dodecyl-3-methylimidazolium bromide ionic liquids (C12mimBr ILs) on a highly oriented pyrolytic graphite (HOPG) surface was studied using in situ X-ray absorption fine structure (XAFS) in combination with in situ XPS and molecular dynamic (MD) simulations. Under no voltage conditions, C12mimBr on the HOPG surface showed increased electron density and reduced first shell distance around Br compared with C12mimBr in the bulk, indicating the existence of the charge and inductive effect between the ILs and HOPG. These behaviours led to the formation of an IL mixed layer structure on the HOPG surface. When a positive voltage of 0.1 V was applied, the coulombic interactions between Br and HOPG mainly induced C12mimBr IL structural transformation into a 'co-adsorbed overscreening' configuration with a Br anion near the IL/HOPG interface. When a positive voltage of 5.0 V was applied, the enhanced coulomb interactions triggered IL structural transformation into an 'alternating anion and cation' configuration with many Br anions near the IL/HOPG interface. MD simulations also verified the structural transformation with the increasing voltage as revealed using XAFS. In situ XPS further confirmed that the Br atoms were closer to the HOPG surface compared with the cations. These results give an important insight into the behaviour of ILs for their electrochemical applications. [ABSTRACT FROM AUTHOR]

Tryptophan (Trp) is an essential amino acid in the human body, and the dysregulation of L -tryptophan (L -Trp) can cause nervous system dysfunction, while D -tryptophan (D -Trp) is involved in the composition of some anticancer agents or cancer treatment drugs. Identification and detection of Trp enantiomers are of great value in clinical diagnosis, biomedicine, and other fields. In this work, an electrochemical chiral sensor Fe-MIL-88-NH2 metal–organic framework–chiral ionic liquid/multi-walled carbon nanotube-MXene-chitosan/glassy carbon electrode (Fe-CIL/MWCNTs-MXene-CS/GCE) is proposed for the chiral recognition of Trp enantiomers (L / D -Trp). The chiral ionic liquid 1-ethyl 3-methylimidazole L -tartrate (CIL) was assembled on the surface of Fe-MIL-88-NH2 metal–organic framework to synthesize the chiral recognition material Fe-CIL, which not only has chiral recognition properties and hydrophilicity but also excellent mechanical properties. The asymmetrical spatial structure of Fe-CIL provides the feasibility for the chiral recognition of L / D -Trp. In addition, differential pulse voltammetry (DPV) was used as the detection method and the DPV peak potential difference (ΔEp) of L / D -Trp is referred to as the index of the chiral recognition performance. Moreover, even in the real sample, the percentage of D -Trp (D -Trp%) in the Trp mixture maintained a good linear relationship with the DPV peak potential (Ep), and this electrochemical chiral sensor showed good reproducibility, stability, and chiral recognition ability. Furthermore, the proposed sensor Fe-CIL/MWCNTs-MXene-CS/GCE has great potential in the field of chiral molecule recognition and determination. [ABSTRACT FROM AUTHOR]