Evaluation of plasmid DNA stability against ultrasonic shear stress and its in vitro delivery efficiency using ionic liquid [Bmim][PF6]

The hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF₆] forms nanostructures with negatively charged plasmid DNA through electrostatic interactions. The formation of plasmid DNA/IL nanostructures was confirmed by measuring the zeta potential of plasmid DNA as well as plasmid DNA/IL nanostructures. The zeta potential of the nanostructures was positive, although plasmid DNA is negatively charged. The positive zeta potential is due to the complexation between plasmid DNA and positively charged ionic liquid [Bmim][PF₆]. The ability of ionic liquid [Bmim][PF₆] to protect plasmid DNA against ultrasonic shear stress was also investigated using an agarose gel electrophoretic assay and showed that ionic liquid stabilizes plasmid DNA against ultrasonication. The plasmid DNA and plasmid DNA/IL nanostructures were subjected to ultrasonic shear stress for different time periods and the biological functionality of pristine plasmid DNA (i.e., expression of the eGFP gene) as well as the self-assembled nanostructures was investigated in vitro using three different cell lines, COS7, HEK293 and HeLa. Ionic liquid [Bmim][PF₆] protected the plasmid DNA against ultrasonic shear stress and also enhanced gene transfection efficiency in vitro. Furthermore, the cytotoxicity of ionic liquid [Bmim][PF₆] was assayed in vitro using all three cell lines and the toxicity was very low. Therefore, the ionic liquid [Bmim][PF₆] stabilizes plasmid DNA against ultrasonic shear stress and also enhances its in vitro delivery efficiency.

The hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF₆] forms ultrasonically stable and functional nanostructures with negatively charged plasmid DNA through electrostatic interactions.     

Syntheses,spectroscopic, redox,and structural properties of homoleptic Iron(III/II) dithione complexes

Two sets of Fe^III/II dithione complexes [Fe^II(ⁱPr₂Dt⁰)₃][PF₆]₂ ([1][PF₆]₂), [Fe^II(Me₂Dt⁰)₃][PF₆]₂ ([2][PF₆]₂), and [Fe^III(ⁱPr₂Dt⁰)₃][PF₆]₃ ([3][PF₆]₃), [Fe^III(Me₂Dt⁰)₃][PF₆]₃ ([4][PF₆]₃), and compound [Fe^III(ⁱPr₂Dt⁰)₃][FeCl₄][PF]₂ ([3][FeCl₄][PF₆]₂) were synthesized from N,N′-diisopropyl piperazine-2,3-dithione (ⁱPr₂Dt⁰) and N,N′-dimethyl piperazine-2,3-dithione (Me₂Dt⁰) ligands. Complexes [1][PF₆]₂–[4][PF₆]₃ have been characterized by NMR, IR, and UV-visible spectroscopies, and by electrochemistry. The molecular structures of [2][PF₆]₂ and [3][FeCl₄][PF₆]₂ have been determined by X-ray crystallography. Complexes [2][PF₆]₂ and [3][FeCl₄][PF₆]₂ both crystallized in the monoclinic space group P2₁/n. Both complexes exhibit distorted octahedral geometry and the three coordinated ligands in each complex exhibit different dithione folding. Complexes [1][PF₆]₂–[4][PF₆]₃ exhibit a single Fe^III/II based couple and three quasi-reversible ligand-based redox couples. The electronic spectra of [1][PF₆]₂–[4][PF₆]₃ show intense MLCT bands that indicate strong mixing between metal and ligand orbitals. DFT calculations were used to provide a framework for understanding the electronic origin of their redox chemistry and spectroscopic features.

Two sets of Fe^III/II complexes, synthesized from N,N′-diisopropyl piperazine-2,3-dithione (ⁱPr₂Dt⁰) and N,N′-dimethyl piperazine-2,3-dithione (Me₂Dt⁰) ligands, exhibit electronically asymmetrical ligands with metal–ligand orbital mixing.     

Synthesis of gemini basic ionic liquids and their application in anion exchange membranes

A gemini-type basic morpholine ionic liquid ([Nbmd][OH]) was synthesized via a two-step method with morpholine, bromododecane and 1,4-dibromobutane as raw materials, and its structure was characterized by ¹H NMR and FT-IR spectroscopy. Meanwhile, a series of anion exchange membranes ([Nbmd][OH]_x–QCS) were prepared with quaternized chitosan (QCS) as the polymer matrix and [Nbmd][OH] as the dopant owing to its strong alkalinity and good solubility. The structures of the [Nbmd][OH]_x–QCS composite membranes were characterized in detail by FT-IR spectroscopy, the OH⁻ conductivity by AC impedance spectroscopy, and the morphological features by scanning electron microscopy (SEM), thermal gravity analysis (TGA), etc. The results show that the [Nbmd][OH]_x–QCS composite membranes have uniform surfaces and cross-section morphology. Increasing the content of [Nbmd][OH] not only enhances the thermal stability but also increases the OH⁻ conductivity; the thermal decomposition temperature of the [Nbmd][OH]₄₀–QCS membrane is nearly 20 °C higher than that of the pristine QCS membrane, and the maximum OH⁻ conductivity is approximately 1.37 × 10⁻² S cm⁻² at 70 °C. The methanol permeability of the [Nbmd][OH]₄₀–QCS membrane in 1 M methanol at room temperature is 2.21 × 10⁻⁶ cm⁻² s⁻¹, which is lower than that of Nafion®115, indicating a promising potential use in alkaline direct methanol fuel cells. Moreover, the [Nbmd][OH]₄₀–QCS membrane exhibits the best alkaline stability of all the membranes prepared in this work, retaining approximately 81% of its initial conductivity after immersion in 3 M KOH solution for 120 h at 70 °C.

A gemini-type basic morpholine ionic liquid ([Nbmd][OH]) was synthesized via a two-step method with morpholine, bromododecane and 1,4-dibromobutane as raw materials, and its structure was characterized by ¹H NMR and FT-IR spectroscopy.     

Performance of butanol separation from ABE mixtures by pervaporation using silicone-coated ionic liquid gel membranes

This work aims at the separation of n-butanol from aqueous solutions by means of pervaporation using membranes based on gelled ionic liquids (IL). These membranes were mechanically stabilized with a double silicone coating using two polydimethylsiloxane (PDMS) films. The first step of the membrane preparation considered the formation of a gelled ionic liquid layer, which was formed using two different imidazolium-based ionic liquids: [omim][Tf₂N] and [bmim][Tf₂N], and two different phosphonium-based ionic liquids: [P_6,6,6,14][Tf₂N] and [P_6,6,6,14][DCA]. The gelation procedure was carried out on a porous paper support using a low molecular weight gelator. The membranes obtained from this method were tested in pervaporation assays to separate butanol from model ABE (Acetone–Butanol–Ethanol) fermentation solutions. These assays were done in an experimental setup especially built for this purpose. The pervaporation performance of these ionic liquid-based membranes was compared to that obtained with a single PDMS layer membrane. From these experimental results, butanol/water selectivity for [P_6,6,6,14][Tf₂N]-based membranes reached a value equal to 892, which is 150 times higher than the value obtained for a single PDMS layer membrane. Simultaneously, for the same IL, the transmembrane fluxes (kg h⁻¹ m⁻²) of butanol and water were 37% and 99.6% lower than the values obtained using a single PDMS layer membrane, respectively. The hydrophobic character of the selected ionic liquid and its relatively high values for the transport parameters can explain this experimental response.

This work aims at the separation of n-butanol from aqueous solutions by means of pervaporation using membranes based on gelled ionic liquids (IL).     

Enhancement of CO2 capture performance of aqueous MEA by mixing with [NH2e-mim][BF4]

Alcohol amine solutions have a high absorption capacity and rate for CO₂ capture, however, there are some shortcomings such as high energy-consumption and low stability. To enhance CO₂ capture performance of aqueous MEA, a functional ionic liquid ([NH₂e-mim][BF₄]) was introduced based on the advantages for CO₂ capture. Absorbents were prepared with the molar concentration ratio of [NH₂e-mim][BF₄] to the 30 vol% aqueous MEA of 0 : 10, 1 : 9, 2 : 8, 3 : 7, 4 : 6 and 6 : 4. The density and the viscosity of the investigated absorbents were measured and the effects of the molar fraction of [NH₂e-mim][BF₄] (n_I) and temperature on CO₂ absorption performance were investigated. CO₂ desorption performance of the solvent at different temperatures was discussed. The stability performance of the absorbent with n_I of 2 : 8 (I/M_2:8) was examined by five consecutive cyclic tests. The results showed that for pure CO₂, the I/M_2:8 displayed the highest absorption performance at 303 K under 1 bar: a comparable CO₂ absorption capacity of the 30 vol% aqueous MEA and a higher CO₂ absorption rate at the later absorption stage. Moreover, with the increase of temperature, CO₂ absorption capacity and rate decreased, while CO₂ desorption efficiency and rate increased. 393 K was chosen as the optimum desorption temperature with the desorption efficiency of 99.31%. The introducing of IL contributed to CO₂ desorption performance of the absorbents significantly. The properties (CO₂ absorption capacity, mass loss, density and viscosity) of the I/M_2:8 during the cycles suggested that the IL-MEA mixture had an excellent stability performance.

Alcohol amine solutions have a high absorption capacity and rate for CO₂ capture, however, there are some shortcomings such as high energy-consumption and low stability.     

Synthesis of novel functional ionic liquids and their application in biomass

A series of dicationic ionic liquids (ILs) including [PF₆][(PYR)C₄(MIM)][Cl], [PF₆][(PYR)C₄(PYR)][Cl], [PF₆][(PYR)C₅(MIM)][Cl], and [PF₆][(PYR)C₅(PYR)][Cl], and monocationic ILs including [(PYR)C₄Cl][PF₆], [(PYR)C₅Cl][PF₆], [(MIM)C₂COOH][PF₆] and [(PYR)C₂COOH][PF₆] were synthesized. Their thermal stability and melting points were determined. Their solubility with organic solvents and the miscibility with water were investigated. These functional ILs are hydrophilic at high temperatures and they are hydrophobic at low temperatures, which enable the effective isolation of the resulting reducing sugar. High yields of reducing sugar were obtained for corn stalk after 8 h (20.73%) and potato starch after 6 h (72.50%) by the treatment with the mixture of [PF₆][(PYR)C₄(PYR)][Cl] and [(PYR)C₂COOH][PF₆]. The reuse of dicationic and monocationic ILs was successfully performed and no significant reduction in yields of reducing sugar was observed. These functional ILs have important implications in the design of homogeneous and heterogeneous systems with water and organic solvents, which could be used to satisfy some specific applications.

A series of dicationic and monocationic ionic liquids (ILs) were synthesized and investigated and it was found that these functional ILs have important implications in the design of homogeneous and heterogeneous systems.     

Thermodynamic,structural and dynamic properties of ionic liquids [C4mim][CF3COO], [C4mim][Br] in the condensed phase,using molecular simulations

In this work a series of thermodynamic, structural, and dynamical properties for the 1-butyl-3-methylimidazolium trifluoroacetate ([C₄mim][CF₃COO]) and 1-butyl-3-methylimidazolium bromide, ([C₄mim][Br]) ionic liquids (ILs) were calculated using Non-polarizable Force Fields (FF), parameterized using a methodology developed previously within the research group, for condensed phase applications. Properties such as the Vapor-Liquid Equilibrium (VLE) curve, critical points (ρ_c, T_c), Radial, Spatial and Combined Distribution Functions and self-diffusion coefficients were calculated using Equilibrium Molecular Dynamics simulations (EMD); other properties such as shear viscosities and thermal conductivities were calculated using Non-Equilibrium Molecular Dynamics simulations (NEMD). The results obtained in this work indicated that the calculated critical points are comparable with those available in the literature. The calculated structural information for these two ILs indicated that the anions interact mainly with hydrogen atoms from both the imidazolium ring and the methyl chain; the bromide anion displays twice the hydrogen coordination number than the oxygen atoms from the trifluoroacetate anion. Furthermore, Non-Covalent interactions (NCI index), determined by DFT calculations, revealed that some hydrogen bonds in the [C₄mim][Br] IL displayed similar strength to those in the [C₄mim][CF₃COO] IL, in spite of the shorter O⁻–H distances found in the latter IL. The majority of the calculated transport properties presented reasonable agreement with the experimental available data. Nonetheless, the self-diffusion coefficients determined in this work are under-estimated with respect to experimental values; however, by escalating the electrostatic atomic charges for the anion and cation to ±0.8e, only for this property, a remarkable improvement was obtained. Experimental evidence was recovered for most of the calculated properties and to the best of our knowledge, some new predictions were done mainly in thermodynamic states where data are not available. To validate the FF, developed previously within the research group, dynamic properties were also evaluated for a series of ILs such as [C₄mim][PF₆], [C₄mim][BF₄], [C₄mim][OMs], and [C₄mim][NTf₂] ILs.

Non-covalent interactions, coordination numbers, RDFs, SDFs, CDFs, and transport properties for the [C₄mim][Br] and [C₄mim][CF₃COO] ionic liquids were determined.     

Synthesis of alkyl polyglycosides using SO3H-functionalized ionic liquids as catalysts

An effective process for synthesis of alkyl polyglycosides (APG) was developed using SO₃H-functionalized ionic liquids (SFILs) as catalysts. Four SFILs, [PSmim][HSO₄], [PSmim][pTSA], [PSPy][HSO₄] and [PSPy][pTSA], were designed and synthesized for APG synthesis. The results indicated that [PSmim][HSO₄] shows the best catalytic performance among these four SFILs, which has a great agreement with the order of their acidities. When the [PSmim][HSO₄] was used as catalyst, the reaction time could be decreased from 24 h to 8 h, and molar ration of n-octanol to glucose could be decreased from 5 : 1 to 3 : 1 under the optimization reaction conditions. In addition, the [PSmim][HSO₄] could be easily regenerated and recycled at least 5 times with slight decrease in catalytic activity. Moreover, the catalytic mechanism of [PSmim][HSO₄] was further investigated by molecular simulation. The high catalytic activity of [PSmim][HSO₄] is attributed to hydrogen bonds between [PSmim][HSO₄] and glucose and n-octanol, which could accelerate the protonation of glucose and removal of hydrogen ions from the hydroxyl in n-octanol.

Alkyl polyglycosides (APG), produced from glucose and fatty alcohols, are one kind of renewable green non-ionic surfactants. It is of great significance to develop a green catalyst reaction system for synthesis of alkyl polyglycosides.     

Effects of amino acid ionic liquids with different cations ([N2Py], [N2222], [P2222], and [C2mim]) on wheat seedlings

The ecotoxicity of four ionic liquids with different cations (N-ethyl-pyridine alanine [N₂Py][Ala], tetraethyl phosphine l-α-amino propionic acid salt [P₂₂₂₂][Ala], 1-ethyl-3-methyl-imidazolium alanine [C₂mim][Ala], and tetraethyl ammonium l-α-amino propionic acid salt [N₂₂₂₂][Ala]) was assessed in hydroponically-grown wheat seedlings at concentrations from 200–1200 mg L⁻¹. The results showed that type of cation has a significant influence on the growth, chlorophyll and nutrient uptake of wheat seedlings (P < 0.05). We observed decreased dry weight and shorter roots and shoots in the treated seedlings with increasing IL concentrations. The contents of Chl a and Chl b in wheat seedlings exposed to ILs showed the trend of firstly increasing followed by a decrease with increasing IL concentrations, but they peaked at different concentrations of ILs. In addition, the exposure of wheat seedling to ILs containing different cations (200–1200 mg L⁻¹) led to first an increase and then a decrease of nitrogen content, and reduced the content of phosphorus and potassium. Moreover, the cellular structures, including nuclei, mitochondria, chloroplasts, cell membranes, and the cell walls of wheat leaf and root were affected to varying degrees by 600 mg L⁻¹ ILs. The negative impacts of ILs on wheat seedlings ranked from high to low were: [N₂Py][Ala] > [N₂₂₂₂][Ala] > [P₂₂₂₂][Ala] > [C₂mim][Ala]. In this work, the relatively stronger toxicity of [N₂Py][Ala] was likely contributed by ethanol, which was used to dissolve [N₂Py][Ala]. Therefore, it is not recommended to use N-ethyl-pyridine alanine ([N₂Py][Ala]) widely in practical applications.

The ecotoxicity of four ionic liquids with different cations was assessed in hydroponically-grown wheat seedlings at concentrations from 200–1200 mg L⁻¹.     

Nano-[Fe3O4@SiO2/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl2] as a nano magnetite Schiff base complex and heterogeneous catalyst for the synthesis of pyrimido[4,5-b]quinolones

Nano-[Fe₃O₄@SiO₂/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl₂] as a nano magnetite Schiff base complex was designed and fully characterized by various analyses such as Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric analysis (DTA), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and transmission electron micrographs (TEM). The presented nano magnetite Schiff base complex was used as a heterogeneous catalyst for the synthesis of pyrimido[4,5-b]quinolones by the reaction of aryl aldehyde, dimedone and 6-amino-1,3-dimethyluracil in EtOH : H₂O (7 : 3) as a solvent at 60 °C.

Nano-[Fe₃O₄@SiO₂/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl₂] as a nano magnetite Schiff base complex was designed and successfully tested for the synthesis of pyrimido[4,5-b]quinolones.     

Synthesis,characterization, and photoluminescent studies of three-coordinate Cu(i)–NHC complexes bearing unsymmetrically-substituted dipyridylamine ligands

A series of heteroleptic three-coordinate Cu(i) complexes bearing monodentate N-heterocyclic carbene (NHC) ligands of the type 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene (SIPr), and bidentate N-donor ligands of the type unsymmetrically-substituted dimethyl dipyridylamine (Me₂Hdpa) and bis(mesityl)biazanaphthenequinone (mesBIAN) have been synthesized. The complexes [Cu(IPr)(3,4′-Me₂Hdpa)]PF₆, 1; [Cu(IPr)(3,5′-Me₂Hdpa)]PF₆, 2; [Cu(IPr)(3,6′-Me₂Hdpa)]PF₆, 3; [Cu(IPr)(mesBIAN)]PF₆, 6; [Cu(SIPr)(3,4′-Me₂Hdpa)]PF₆, 7; [Cu(SIPr)(3,5′-Me₂Hdpa)]PF₆, 8; and [Cu(SIPr)(3,3′-Me₂Hdpa)]PF₆, 11 have been characterized by ¹H and ¹³C NMR spectroscopies, elemental analysis, cyclic voltammetry, and photophysical studies in solid and solution phase. Single crystal X-ray structures were obtained for all complexes except 11. The crystallographic data reveal a mononuclear structure for all complexes with the copper atom ligated by one C and two N atoms. The UV-Vis absorption spectra of all dipyridylamine complexes in CH₂Cl₂ show a strong ligand-centered absorption band around 250 nm and a strong metal-to-ligand charge transfer (MLCT) band around 300 nm. When irradiated with UV light, the complexes exhibit strong emission maxima at 453–482 nm with photoluminescence quantum yields (PLQY) ranging from 0.21 to 0.87 in solid state. While the PLQY values are comparable to those of the symmetrical [Cu(IPr)(Me₂Hdpa)]PF₆ complexes, a stabilizing CH–π interaction has been reduced in the current systems. In particular, complex 3 lacks any strong CH–π interaction, but emits more efficiently than 1 and 2 wherein the interactions exist. Structural data analysis was performed to clarify the role of ligands'' plane angle and the NH/CH⋯F interactions to the observed light interaction of unsymmetrical [Cu(NHC)(Me₂Hdpa)]PF₆ complexes. DFT calculations were performed to assist in the assignment of the electronic structure and excited state behavior of the complexes.

The photoluminescent Cu(i)–NHC complexes bearing unsymmetrical dipyridylamine ligands have been synthesized and characterized. The structure–light reactivity has been elucidated.     

Excess chemical potential of thiophene in [C4MIM] [BF4, Cl,Br, CH3COO] ionic liquids,determined by molecular simulations

The excess chemical potential of thiophene in imidazolium-based ionic liquids [C₄mim][BF₄], [C₄mim][Cl], [C₄mim][Br], and [C₄mim][CH₃COO] were determined by means of molecular dynamics in conjunction with free energy perturbation techniques employing non-polarizable force fields at 300 K and 343.15 K. In addition, energetic and structural analysis were performed such as: interaction energies, averaged noncovalent interactions, radial, and combined distribution functions. The results from this work revealed that the ionic liquids (ILs) presenting the most favorable excess chemical potentials ([C₄mim][BF₄], [C₄mim][CH₃COO]) are associated with the strongest energetic interaction between the thiophene molecule and the ionic liquid anion, and with the weakest energetic interaction between the thiophene molecule and the ionic liquid cation.

Excess chemical potential of thiophene in imidazolium-based ionic liquids [C₄mim][BF₄], [C₄mim][Cl], [C₄mim][Br], and [C₄mim][CH₃COO] determined by molecular simulations.

In order to consider polarizability effects, not included in the classical forcefields, ab initio molecular dynamics (AIMD) were carried to elucidate a more representative molecular environment. The radial distribution functions (RDF) obtained from the AIMD indicated that the thiophene molecule finds the IL anions at closer distances than the imidazolium ring cation; also, the ionic liquids [C₄mim][BF₄] and [C₄mim][CH₃COO] presented more defined RDF peaks for the sulfur atom paired with hydrogen atoms within the imidazolium ring, in comparison with the thiophene–anion pair distributions, and the inverse RDF phenomena were observed in the other two ILs. Furthermore, the combined distribution functions signaled a series of interactions between thiophene and IL cation, including π–π thiophene–cation stacking (face to face, offset and edge to face), thiophene-alkyl chain interactions and hydrogen bonding between thiophene and the IL anion.The averaged noncovalent interactions determined from ab initio molecular dynamic trajectories showed that most of the interactions between the thiophene and IL ions are not strong; nevertheless, these interactions, according to the thermal fluctuation index, are stable throughout the entire simulation time.     

The shiny side of copper: bringing copper(i) light-emitting electrochemical cells closer to application

Heteroleptic [Cu(P^P)(N^N)][PF₆] complexes, where N^N is 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me₂bpy), 4,5,6-trimethyl-2,2′-bipyridine (4,5,6-Me₃bpy), 6-(tert-butyl)-2,2′-bipyridine (6-tBubpy) and 2-ethyl-1,10-phenanthroline (2-Etphen) and P^P is either bis(2-(diphenylphosphino)phenyl)ether (POP, PIN [oxydi(2,1-phenylene)]bis(diphenylphosphane)) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos, PIN (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)) have been synthesized and their NMR spectroscopic, mass spectrometric, structural, electrochemical and photophysical properties were investigated. The single-crystal structures of [Cu(POP)(5,5′-Me₂bpy)][PF₆], [Cu(xantphos)(5,5′-Me₂bpy)][PF₆], [Cu(POP)(6-tBubpy)][PF₆], [Cu(POP)(4,5,6-Me₃bpy)][PF₆]·1.5Et₂O, [Cu(xantphos)(4,5,6-Me₃bpy)][PF₆]·2.33CH₂Cl₂, [Cu(POP)(2-Etphen)][PF₆] and [Cu(xantphos)(2-Etphen)][PF₆] are described. While alkyl substituents in general exhibit electron-donating properties, variation in the nature and substitution-position of the alkyl group in the N^N chelate leads to different effects in the photophysical properties of the [Cu(P^P)(N^N)][PF₆] complexes. In the solid state, the complexes are yellow to green emitters with emission maxima between 518 and 602 nm, and photoluminescence quantum yields (PLQYs) ranging from 1.1 to 58.8%. All complexes show thermally activated delayed fluorescence (TADF). The complexes were employed in the active layer of light-emitting electrochemical cells (LECs). The device performance properties are among the best reported for copper-based LECs, with maximum luminance values of up to 462 cd m⁻² and device half-lifetimes of up to 98 hours.

Heteroleptic copper(i) complexes with bisphosphanes and astutely tuned N^N chelating ligands as emitters give bright LECs with record-breaking stability.     

Correction: Split-anion solvent extraction of light rare earths from concentrated chloride aqueous solutions to nitrate organic ionic liquids

Correction for ‘Split-anion solvent extraction of light rare earths from concentrated chloride aqueous solutions to nitrate organic ionic liquids’ by Mercedes Regadío et al., RSC Adv., 2018, 8, 34754–34763, DOI: 10.1039/c8ra06055j.

The authors regret that an incorrect figure caption was given for Fig. 5. The correct version is presented below.Open in a separate windowFig. 5Viscosity as a function of the temperature and the organic phase composition: (1) after loading 39 g L⁻¹ of REE in 20 v% Cy923 in [C101][NO₃], (2) pure [C101][NO₃], (3) 20 v% Cy923 in [C101][NO₃] and (4) pure Cy923.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Self-assembly of a short-chain ionic liquid within deep eutectic solvents

Ionic liquids (ILs) and deep eutectic solvents (DESs) are receiving increased attention from both academic and industrial research due to their immense application potential. These designer solvents are environmentally friendly in nature with tunable physicochemical properties. In the present investigation, we have studied the aggregation behavior of a short-chain IL 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] within aqueous DESs using fluorescence, UV-vis, dynamic light scattering (DLS) and FT-IR spectroscopic techniques. We have prepared two DESs, ChCl–urea and ChCl–Gly, which are obtained by heating a mixture of an ammonium salt choline chloride with hydrogen bond donor urea or glycerol, respectively, in 1 : 2 molar ratios. The local microenvironment and size of the aggregates are obtained from steady state fluorescence (using pyrene and pyrene-1-carboxaldehyde as polarity probes) and DLS measurements, respectively. DLS results shows that IL [Bmim][OS] forms relatively larger micelles within the aqueous solution of DES ChCl–urea (avg. hydrodynamic radii = 209 nm) than compared to ChCl–Gly (avg. hydrodynamic radii = 135 nm). A significant decrease in the critical micelle concentration and increase in the aggregation number (N_agg) are observed within DES solutions as compared to that in water, thus indicating that the micellization process of the IL [Bmim][OS] is much favored in the DES solutions. Molecular interactions of [Bmim][OS] in DESs are revealed from FT-IR spectroscopic investigation. Furthermore, these systems were applied to study the IL-drug binding of the antidepressant drug promazine hydrochloride (PH).

Self-assembly of short-chain imidazolium-based ILs within DESs have been investigated by fluorescence, UV-Vis, DLS and FT-IR spectroscopy. Further, these micellar systems [Bmim][OS]-DESs are utilized to study the IL-drug binding of an antidepressant drug (PH).     

Selection of a suitable ZIF-8/ionic liquid (IL) based composite for selective CO2 capture: the role of anions at the interface

The effective capture of CO₂ from the atmosphere is much needed to reduce its environmental impact. The design and development of CO₂ capturing materials is getting much attention. A zeolitic imidazolate framework (ZIF) can replace many of the conventional materials in gas separation due to its stability and high performance. Here, we analyzed the effect of encapsulation of ionic liquids (ILs) into the pores of ZIF-8 for selective CO₂ capture and separation. The [BMIM]⁺ cation with a series of anions was selected to study suitable carbon capture materials using density functional theory (DFT) approaches. Our calculations suggest that the nitrogen containing anions are not well adsorbed on the ZIF-8 surface but their gas separation performance is not affected by these interfacial interactions. This is confirmed from the CO₂/N₂ and CO₂/CH₄ selectivity of these composites, calculated using grand canonical Monte Carlo (GCMC) simulations. A suitable force field for the composites was identified by comparing the available force fields with the experiments. The IL@ZIF-8 composite shows better CO₂ selectivity compared to pristine ZIF-8. Fluorinated hydrophobic anions (such as [BF₄]⁻, [PF₆]⁻ and [Tf₂N]⁻) in the composites show better CO₂ adsorption and significant CO₂ selectivity than pristine ZIF-8, especially at low pressure. The nature of the anion plays an important role in CO₂ separation, rather than its stability at the pores of ZIF-8. Close scrutiny of the results reveal that the CO₂ selectivity of these composite materials depends on the anion of the IL and thus through the selection of a suitable anion we can significantly enhance the CO₂ selectivity for different flue gas mixtures. Our molecular level design shows that the selection of suitable anions in IL based composites is very important in identifying potential carbon capture materials for industrial applications.

The interfacial stability of hydrophilic/hydrophobic IL incorporated ZIF-8 is identified and the CO₂ selectivity depends on the fluorinated anions in the IL.     

In situ constructed zeolite membranes on rough supports with the assistance of reticulated hydrotalcite interlayer

Zeolite membranes with unique physical and chemical properties are emerging as attractive candidates for membrane separation. However, defects in the zeolite layer seriously affect their molecular sieving performance. In this study, a novel strategy for preparing compact zeolite membranes on rough supports with the assistance of a reticulated hydrotalcite layer was developed. The reticulated hydrotalcite layer was grown on the inner surface of a 170 mm length ceramic tube by an in situ hydrothermal method, and a NaA zeolite membrane was prepared on this reticulated layer by the microwave-heating method. The hydrotalcite interlayer could not only improve the smoothness and regularity of the surface of the support but also fix the Si/Al active ingredients using its reticulate structure, finally effectively improving the quality and stability of the zeolite layer. The optimal molar ratio of the synthesis solution for the synthesis of the zeolite membrane was 3Na₂O : 2SiO₂ : Al₂O₃ : 200H₂O. The permeance flux of H₂ through the zeolite membrane synthesized under the optimal conditions was high as 0.47 × 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹, and its permselectivity for H₂ over N₂ was 4.7, which was higher than the corresponding Knudsen diffusion coefficient. This study provides a new idea for the preparation of defect-free membranes on rough supports.

Reticulated hydrotalcite interlayer controls infiltration of active ingredients into the support, improving the quality and stability of the zeolite membrane.     

Design,characterization and catalytic evaluation of halometallic ionic liquid incorporated Nd2O3 nanoparticles ([smim][FeCl4]−@Nd2O3) for the synthesis of N-aryl indeno pyrrole derivatives

Silica modified imidazolium [smim] based halometallic ionic liquids, [smim][MCl₄] (M = Fe, Cu and Zn), were synthesized for the evaluation of acidic and catalytic properties. Among these ILs, [smim][FeCl₄]⁻ was used for the preparation of heterogeneous catalyst ([smim][FeCl₄]⁻@Nd₂O₃) by simple immobilization of IL on Nd₂O₃ nanoparticles. The structure of [smim][FeCl₄]⁻@Nd₂O₃ was established by various techniques including FTIR, Raman, UV-vis DRS, powder XRD, SEM/EDX, elemental mapping, TEM, TGA, EPR and XPS analyses. The stability of nano-catalyst, [smim][ FeCl₄]⁻@Nd₂O₃, was established with the help of zeta potential analysis which showed a value of −40.32 mV lying under the stability range. Potentiometric titration with n-butyl amine was used to evaluate the acidic properties of [smim][MCl₄] as well as [smim][FeCl₄]⁻@Nd₂O₃. The catalytic potential of the material was probed through the one pot synthesis of N-aryl indeno pyrrole derivatives. The results showed excellent performance of the material by producing a high yield (98%) of indeno pyrrole derivatives. A recyclability experiment revealed that the catalyst was efficient in up to five cycles with insignificant loss in catalytic activity. The evaluation of green metrics indicated the sustainability of the present protocol in terms of high atom economy and low E-factor.

Silica modified imidazolium based halometallic ionic liquids, [smim][MCl₄] and [smim][FeCl₄]⁻@Nd₂O₃ were synthesized for the evaluation of acidic and catalytic properties.