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In this paper, the functionalized ligand 2-(imidazole-1-yl)terephthalic acid was obtained by grafting an imidazole group onto 2-bromoterephthalic acid. Then, defective MOFs were synthesized with Hf ions and the ligand in the presence of monocarboxylic acid acting as a modulator, and NHC (nitrogen heterocyclic carbene)–CO2 adducts were grafted onto the Hf-based MOFs to catalyze the cycloaddition reaction of epoxides with CO2 to produce cyclic carbonates under green conditions of ambient pressure and being solvent- and cocatalyst-free. The mesopore defects created by the modulator and DMC (dimethyl carbonate) solvothermal etching, the enhanced Lewis acidity of the Hf clusters and the grafted NHC–CO2 adducts can improve synergistically the catalytic performance of the MOFs via decreasing activation energy, promoting mass transfer and providing more active catalytic sites. The results show that the highest conversion rate reaches 81.64% at 100 °C and 10 h for the cycloaddition reaction of CO2 with epichlorohydrin. Finally, a possible reaction mechanism was proposed based on characterization and catalytic measurement. [ABSTRACT FROM AUTHOR]

In this study, a novel and highly efficient "turn-off" fluorescence imidazole-based sensor (BIB) with a symmetric structure was synthesized by a four-step reaction, from o-phenylenediamine, 6-bromo-2-pyridinecarboxaldehyde, and 1-bromohexane. The sensing mechanism was confirmed via fluorescence titration, HRMS, and 1HNMR techiniques. The results showed that the binding ratio of BIB and Ag+ was 1 : 1 in a DMF-HEPES (pH 7.4) solution (9 : 1, v/v). The fluorescence response of BIB exhibited a good linear response within the Ag+ concentration ranging from 2 × 10−7 to 8 × 10−6 mol L−1, and the limit of detection was calculated to be 4.591 × 10−8 mol L−1. BIB was successfully applied to the detection of Ag+ in water samples with recoveries of 97.25–109.50% and relative standard deviations (RSD) of 1.14–2.45%. In addition, BIB can successfully be applied to qualitatively and quantitatively identify Ag+ in water by test paper strips of BIB, which is fast and convenient. This provides a possible potential for the rapid monitoring of metal ions by sensors in environmental research. [ABSTRACT FROM AUTHOR]

In the current paper, we have successfully synthesized three new mercury coordination polymers with fascinating structures and properties via a flexible sulfur donor ligand, namely, {[Hg(μ2-Cl)(μ2-Ls)]} n [BF4] n (1), {[Hg(μ2-Cl)(μ2-Ls)]} n [ClO4] n (2), and [Hg(SCN)2(μ2-Ls)] n (3) [Ls = 1,1-bis(3-methyl-4-imidazoline-2-thione)methane]. These complexes have been characterized by means of different techniques such as single crystal X-ray crystallography, FT-IR, elemental analysis (CHNS), UV-Vis, PXRD, BET, and TGA. Suitable single crystals of all complexes were obtained using the branch tube method with a very high yield and good stability due to the high affinity of mercury to bind to the thione groups. The cationic moieties of polymers 1 and 2 were isostructural, with a HgCl2S2 coordination core structure. The voids of the quasi-hexagonal packing of the columnar chains were occupied by unbonded tetrahedral BF4− ions in 1 and perchlorate anions in polymer 2. Polymer 3 has a less distorted tetrahedral geometry than 1 and 2, with a HgS4 core structure. By considering the thiophilicity of mercury, a thioamide-based Ls ligand was used to detoxify Hg(II) into insoluble polymers 1–3. The results of an MTT assay for (HepG2) liver cells confirmed the excellent cytoprotective effect of this ligand against mercury. Based on IC50 calculations, their toxicity was in order of polymer 1 > polymer 2 > polymer 3. These polymers were also considered as adsorbents for the reversible removal of iodine from solution and the kinetics of the process has been studied in detail. Interestingly, all of them showed an excellent stability and high capacity, in order of 763.53 mg g−1, 877.10 mg g−1, and 905.31 mg g−1 for polymers 1–3, respectively. [ABSTRACT FROM AUTHOR]

Nowadays, nitrogen rich compounds are the key research objects for high-energy materials. In this paper, a novel nitrogen rich energetic compound (NABTI) and its salt (4) with bis(tetrazole)imidazole as the skeleton were synthesized by simple steps. Their detailed structural data and stability parameters were obtained through experiments, and the internal relationship between them was theoretically analyzed. The results show that they both have regular planar configurations and layer-by-layer packing patterns, and the 3D hydrogen-bonding network and π–π interactions inside the crystals weaken their sensitivity to mechanical stimuli. As the most direct parameter reflecting the energy level, the detonation velocity (D) and detonation pressure (P) of the compounds in the study were calculated through the EXPLOV5 software package. The calculation results showed that NABTI exhibited a better detonation performance (D = 8329 m s−1 and P = 31.4 GPa) than the same type (triazole–tetrazole, NATT) of compound. The advantages of NABTI, such as high nitrogen content, high energy and simple synthesis, fully demonstrate its practicality. [ABSTRACT FROM AUTHOR]

Nitrogen-based heterocycles such as pyrazole, imidazole, 1,2,4-triazole, benzimidazole, and benzotriazole substituted fused pyran derivatives (6a–e, 8a–e, 10a–e, 12a–e, & 14a–e) have been synthesized and tested for their in vitro anticancer efficacies against MCF7, A549, and HCT116 cancer cell lines. Among the compounds, 6e, 14b, and 8c were identified as the most potent against MCF7, A549, and HCT116, with IC50 values of 12.46 ± 2.72 μM, 0.23 ± 0.12 μM, and 7.58 ± 1.01 μM, respectively. Further studies demonstrated that these compounds can change cellular and nuclear morphology and inhibit colony formation in the tested cancer cells. They also remarkably block/inhibit the cell cycle progression of cancer cells at various phases. DNA damage analysis and apoptosis studies revealed that these compounds have the potential to induce DNA double-strand breaks and apoptosis. In silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the potent compounds were assessed, revealing that all the compounds exhibited favorable pharmacokinetic and toxicological properties. The potent compounds identified from this study can be considered as a lead for further drug design and development. [ABSTRACT FROM AUTHOR]

The design and development of smart materials in developing advanced sensing platforms for volatile organic compounds (VOCs) have attracted increasing attention. π-Conjugated small organic building blocks, which can self-assemble into well-ordered superstructures, offer multiple advantages of high surface area, unique optoelectronic properties, good chemical/thermal stability, and host–guest interaction ability, which make them appealing candidates for VOC sensing. However, the fabrication of stable and well-ordered self-assembled structures from π-conjugated building blocks with appreciable electrical properties and their successful employment in the selective detection of VOCs remains a challenge due to the non-specific interaction between monomers during self-assembly and with other existing VOCs during sensing, respectively. Herein, we have designed and synthesized three phenanthro[9,10-d] imidazole-based ligands; L1, L2, and L3 with three different hydroxy benzene analog substitutions at the 2-position and their corresponding Zn(II) and Cd(II) complexes followed by fabrication into well-ordered superstructures with discrete morphologies for the selective detection of acetone vapour by measuring the contact potential difference using the Scanning Kelvin Probe (SKP). Several experimental analyses suggest that a precise combination of the operative non-covalent interactions along with the metal–ligand interactions drive the overall self-assembly process of these metal coordinated π-conjugated probes and could lead to generation of well-ordered various superstructures. Surface photovoltage measurements using the SKP on the surfaces of films coated with superstructures derived from these metal complexes were carried out both in the dark and under UV (Ultra-Violet) illumination in the presence of different vapours of VOCs. As per the results, under UV illumination, the thin film fabricated with superstructures derived from Cd complexes ((L1)2M, (L2)2M and (L3)2M; M = Cd(II)) exhibit higher sensitivity and selectivity towards acetone in comparison with Zn(II) complexes-based superstructures. Thus, these self-assembled structures generated by the metal complexes of these π-conjugated molecular probes may provide new insights into the fabrication of organic electronic devices for gas sensors. [ABSTRACT FROM AUTHOR]

The development of carbon-based catalysts to substitute Pt-based catalysts for the oxygen reduction reaction is highly important for promoting their practical application in energy conversion. Herein, we prepare Zn, Fe and N-codoped porous carbon (Zn/Fe-NC-x) as a cathode catalyst via a facile one-step pyrolysis predesigned bimetallic zeolitic imidazole framework. Systematic electrochemical studies demonstrated that the synthesized Zn/Fe-NC-0.5 exhibits higher electrocatalytic activity towards the oxygen reduction reaction. In particular, Zn/Fe-NC-0.5 has a smaller charge transfer resistance, larger exchange current density, and much higher open circuit potential and mainly proceeds via an efficient four-electron pathway. A microbial fuel cell equipped with the synthesized catalyst exhibited the highest maximum power density of 1954 ± 20 mW m−2. In addition, the effects of the iron doping content on the oxygen reduction reaction performance and maximum power density were evaluated: a moderate Fe doping content plays a crucial role in improving the catalytic activity, and the synergistic effect of Zn, Fe and N codoping promotes cathodic performance. In brief, Zn/Fe-NC, which has the advantages of facile synthesis, environmental friendliness and excellent electrochemical activity, is a promising Pt-alternative catalyst for the oxygen reduction reaction in air-cathode microbial fuel cells. [ABSTRACT FROM AUTHOR]

The nature of π-hole spodium bonds in the HgLCl2⋯ZH3/CH2Y complexes (L = pyrrole 1, pyrazole 2, imidazole 3, pyridine 4, pyridazine 5, and pyrimidine 6; Z = N, P, As, and Sb; Y = O, S, Se, and Te) has been studied using theoretical calculations. The electrophilicity of the π-hole in the tri-coordinated HgII complexes varies with the type of N-heterocyclic ligand. The strength and nature of the π-hole spodium bond is closely related to the properties of the Lewis bases. In the case of HgLCl2⋯ZH3, the strength of the π-hole spodium bond weakens as the nucleophilicity of the base decreases, following the sequence HgLCl2⋯NH3 > HgLCl2⋯PH3 > HgLCl2⋯AsH3 > HgLCl2⋯SbH3. The Hg⋯Z spodium bonds change from a partially covalent interaction to a close-shelled noncovalent interaction. The nucleophilic ability of CH2Y decreases in the order CH2O > CH2S > CH2Se > CH2Te, while the strength of the π-hole spodium bond follows the order HgLCl2⋯OCH2 < HgLCl2⋯SCH2 < HgLCl2⋯SeCH2 < HgLCl2⋯TeCH2. The Hg⋯Y spodium bond undergoes a transition from a close-shelled noncovalent to a partially covalent interaction, resulting in an incremental increase in the degree of covalence. The Hg⋯Te spodium bond exhibits certain characteristics resembling those of a coordinate covalent bond. The inter-orbital interactions observed in the formation of the HgLCl2⋯YCH2 complexes appear to be significantly stronger compared to those observed in the HgLCl2⋯ZH3 complexation. [ABSTRACT FROM AUTHOR]

With a rapid expansion in applications of epoxy resins (EP) and derived composites, there is a high demand for improving their flame retardant and dielectric properties. In this work, a facile and convenient strategy for loading a dimethyl methylphosphonate (DMMP) flame retardant into the channels of ZIF-8 (zeolitic imidazolate framework) was developed, followed by the assembly of a hybrid ZIF-8@DMMP material with epoxy resin (EP). The obtained MOF-containing hybrid EP composites, abbreviated as 820/EP (with 20 wt% ZIF-8) and 8 FR20/EP (with 20wt% ZIF-8@DMMP), were fully characterized and shown to feature superior flame retardant behavior, contributing to an enhanced safety of such material in terms of total smoke suppression, lower levels of total heat release and carbon monoxide generation. The results demonstrated that the formation of an intumescent dense char layer restrained further combustion, thus enabling this composite material to feature a better flame retardant performance. Besides, the composite exhibited a dielectric permittivity and dielectric loss of as low as 3.0 at a high frequency, which significantly outperforms the neat epoxy resin. This work thus showcases a simple and efficient route to enhance dielectric and flame retardant properties of polymeric epoxy resins, while merging the inherent porosity of ZIF-8 and traditional flame retardant behavior of DMMP. [ABSTRACT FROM AUTHOR]

A new iodine-rich imidazole derivative 1,4-bis(4,5-diiodo-1H-imidazol-1-yl)butane (bimbI4, 1) features multiple I⋯I interactions in the solid state. Using 1 as a precursor, we prepared 1D and 2D coordination polymers of Co(II) and Cu(I) – {[Co(bimbI4)Cl2]·1.5DMF}n (2) and {[Cu2I2(bimbI4)]}n (3), respectively, also featuring extended systems of halogen bonds within their structures. [ABSTRACT FROM AUTHOR]

Eutectic solvents are tunable for targeted applications through the functional groups in their hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) components, as well as the HBA : HBD composition ratio. This study examines the properties of choline-based eutectics containing imidazole, phenol, pyrrole-2-carbonitrile, and 1,2,4-triazole HBAs, and ethylene glycol, 1,2-propylene glycol, and ethanolamine HBDs. The viscosity, conductivity, degree of hydrogen bonding, thermal stability, and solvatochromic properties are examined as a function of HBA, HBD, and the composition. These studies revealed a predominant dependence of physical properties on the HBD and determined that the strong hydrogen bonding in phenol and imidazole-based systems lead to higher viscosities and lower conductivities – critical parameters for CO2 capture and electrochemical conversion. The developed eutectic solvents were further evaluated in terms of their CO2 capture capacities and electrochemical stabilities. Solvatochromic properties were found to correlate with CO2 capacities, demonstrating the tunability of these solvents for CO2 capture. The quantitative structure–property relationship (QSPR) analysis demonstrated the ability to predict viscosities and CO2 capture capacities (<25% deviation) through a multi linear regression method utilizing five molecular descriptors. This work highlights the role of functionalized HBAs and HBDs in the physical, thermal, and electrochemical properties of eutectic solvents as they relate to CO2 capture and electrochemical processes. [ABSTRACT FROM AUTHOR]

Environment-benign one-pot three-component cycloadditions of diazo compounds, nitrosoarenes and vinyl pyrimidines, or vinyl purines, or vinyl imidazoles, or vinyl triazoles or vinyl indole have been developed. This catalyst- and additive-free strategy could efficiently introduce the isoxazolidine skeleton into nucleoside analogues, oxazole molecules and indole derivatives to provide diverse classes of isoxazolidinyl pyrimidine nucleoside analogues, isoxazolidinyl purine nucleoside analogues, isoxazolidinyl imidazoles, isoxazolidinyl triazoles and isoxazolidinyl indole with moderate to good yields for most substrates. [ABSTRACT FROM AUTHOR]

As important building blocks in natural products and organic synthesis, thioethers have a wide range of potential applications. Herein, polyoxometalate-based ionic liquids (POM-ILs-SO3H) derived from N-alkyl imidazole were synthesized and used for the first time for the thiolation of alcohols to construct C–S bonds in a series of benzyl thioethers. This type of POM-ILs-SO3H catalyst exhibited high catalytic activity, providing up to 98% yield of thioether within 1 h at 70 °C. The alkyl chain length of the imidazole had a certain effect on the solubility of the POM-ILs-SO3H catalysts in the reaction solvent, and then affected their catalytic activity. The catalytic system had a wide substrate scope and was suitable for the reaction of tertiary and secondary benzyl alcohols with thiophenols or cycloalkyl thiols. In particular, [PIMPS]3PW12O40 (PIM = 1-propylimidazole, PS = propane sulfonate) as a reversible phase transformation-type catalyst, combining the advantages of homogeneous and heterogeneous catalysts, exhibited high activity and good recyclability with only a slight decrease in the yield after five runs. Additionally, a carbocation mechanism was proposed for the thiolation reaction of alcohols. [ABSTRACT FROM AUTHOR]

A series of 6-oxo-3-(1,2,4,5-substituted-1H-imidazol-3-ium-3-yl)-3,6-dihydro-1,2,4,5-tetrazin-3-ides (3a–3z, 3aa–3ak) was synthesized with medium to good yield by the reaction of 3,6-dichloro-1,2,4,5-tetrazine with a variety of substituted imidazoles in the presence of trace water in solvents. The quinoidal-like structure of these compounds was demonstrated via spectroscopic methods, X-ray diffraction techniques, and computational chemistry. Additionally, water–18O was used to prove that the oxygen in tetrazinone comes from the water in solvents via high-resolution mass spectrometry (HRMS). Moreover, a possible mechanism of aromatic nucleophilic substitution is proposed. [ABSTRACT FROM AUTHOR]

Metal ions of the later part of the first-row transition series (Fe, Co, Ni, Cu, and Zn) can form bonds through the carboxylate, hydroxyl, thiol, and imidazole side chains of proteins and those bonds are significantly more stable than those formed by non-transition metals. Their adventitious binding to protein surfaces provides a great platform for maintaining the native structure of many biologically significant proteins and thus inhibiting the self-aggregation phenomenon of proteins. Aggregation followed by deposition of proteins used for therapeutic purposes either at the site of administration in vivo or during storage conditions in vitro is a major concern. In this work, human insulin is induced to form 'amyloid fibrils' at acidic pH and elevated temperature and then the inhibitory activities of two transition metal ions Fe3+ and Cu2+ towards insulin amyloid fibrillation were investigated. The results show that the formation of β-sheet-rich fibrillar structures was inhibited more with Fe3+ than Cu2+-treated insulin. Dynamic light scattering and circular dichroism proved that Cu2+ was effective at lowering the interaction ratios with insulin, yet Fe3+ was effective in maintaining the size as well as the alpha-helical conformation of monomeric insulin. This metal complex (insulin-Fe3+ or insulin-Cu2+) delayed the nucleation step of aggregation and Fe3+ is far better than Cu2+ in this endeavor. However, both of the metal ions proved their effectiveness in preventing amyloid fibrillation in vitro and can modulate the morphology of the aggregates as revealed by TEM studies. Overall the two transition metal ions Fe3+ and Cu2+ employed in this investigation are essential micronutrients too and are required in minute concentrations. The present study will encourage the applications of transition metal ions Fe3+ and Cu2+ as effective interrupters of amyloidogenesis in aggregation-prone proteins showing pathogenic amyloid deposition. [ABSTRACT FROM AUTHOR]

The thermosensing and thermochromic behavior of one of our recently reported terpyridyl-imidazole based ternary europium tris-(β-diketonate) complexes of the composition [Eu(tta)3(tpy-HImzphen)] (tta = 2-thenoyltrifluoroacetone and tpy-HImzphen = 2-(4-[2,2′:6′,2′′] terpyridin-4′-yl-phenyl)-1H-phenanthro[9,10-d]imidazole) has been thoroughly investigated in this work. The said Eu(III) complex exhibits magnificent thermosensing as well as thermochromic properties and can be recommended as an excellent temperature sensor in a wide temperature domain of 273–343 K in terms of both emission intensity ratio (Sm = 5.78% K−1 at Tm = 343 K, δT = 0.012 K) and lifetime values (Sm = 3.36% K−1 at Tm = 333 K, δT = 0.009 K) or even in terms of its emitting color (red at 268 K, violet at 303 K, and blue at 343 K). Additionally, it displays remarkable solvent-induced luminescence behavior by displaying various emitting colors instead of its sole characteristic red emission upon varying the nature of the solvent. Finally, amalgamating these two features, we are able to attain white light emission (Commission Internationale de l'Eclairage coordinates: x = 0.34, y = 0.38) at 283 K from a single component. A plausible energy transfer mechanism has also been proposed in light of the existence of the ligand-to-metal charge transfer (LMCT) state as the quencher. [ABSTRACT FROM AUTHOR]

A series of tridentate copper(II) N-heterocyclic carbene (NHC) complexes with imidazole, benzimidazole, and 5,6-dimethylbenzimidazole azole rings were synthesized and comprehensively characterized via X-ray crystallography, ESI-MS, cyclic voltammetry, and UV-Vis and EPR spectroscopic studies. These complexes were then utilized for the optimization of ketone reduction under sustainable conditions using 2-acetylpyridine and phenylsilane. The relationships between product formation, temperature, reaction time, and catalyst loading for the hydrogenation reactions are covered in detail. Reduction of eighteen different aliphatic, cyclic, and aromatic ketones were demonstrated, which were compatible to produce the corresponding products in moderate to good yields. These systems were used to develop related DNA-hybrid catalytic systems, but only supported weak enantioselectivity. Further thermodynamic experiments showed Cu-NHC complexes did not demonstrate specific binding to DNA, which is consistent with their limited selectivity. [ABSTRACT FROM AUTHOR]

Salen-based octahedral trans metallo-salen complexes with monodentate co-ligands may exist as several conformational isomers, including stepped and umbrella shaped conformations. However, the factors governing the selective isolation of a particular conformer have not been investigated properly. In this report, six mononuclear cobalt(III) complexes (1–6) with a tetradentate salen-type Schiff base ligand, N,N′-bis(3-methoxy-5-methylsalicylidene)-ethane-1,2-diamine (H2L), and different heteroaromatic co-ligands (pyridines, imidazole and pyrazole) have been synthesized and characterized to unveil the influence of heteroaromatic co-ligands on the conformational (stepped versus umbrella) selectivity of the resulting complexes. X-ray crystallography reveals that the structures of 1–6 are eventually similar with only differences in the coordinated heteroaromatic moieties at axial positions and the accommodation of a different number of lattice solvent/guest molecules in the crystal voids. Interestingly, although a landscape of intermolecular non-covalent interactions are present in the solid state in these systems, the pyridyl co-ligands exclusively stabilize the umbrella-shaped conformation, while five-membered heteroaromatic bases prefer the stepped-shaped conformation, disclosing that the different degrees of intramolecular interactions (repulsion/attraction) of the six and five membered heteroaromatic ligands at the axial positions play the most important role in the selective stability of the different conformations in the solid state. All these complexes exhibit efficient catalytic activity mimicking the functions of phenoxazinone synthase and catechol oxidase. The catalyst recyclability test was also performed and it showed a very negligible change in catalytic efficiency even after five catalytic cycles. Theoretical calculations were performed to gain in-depth understanding of the preference of pyridine ligands for the umbrella-shaped conformation and the five-membered ring co-ligands for the stepped-shaped one, as well as for the mechanistic investigation of the aerobic oxidation of o-aminophenol in the presence of 1–6 as catalysts. [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) framework with the general formula {[Cu(μ3-dmg)(im)2]·3H2O}n (1) was synthesized using an aliphatic dicarboxylic acid linker 2,2-dimethylglutarate (dmg2−) and nitrogen-containing imidazole ligand (im) under conventional methods. 1 was characterized by FT-IR spectroscopy, elemental analysis, single crystal and powder X-ray diffractions, and thermal analysis techniques. Additionally, the optical and topological properties of compound 1 were also investigated. The single crystal X-ray data exhibit that 1 is an interesting 3D framework and it has a I41/a space group, which originates from two imidazole ligands, one dmg and three lattice water molecules. Topologically, 1 displays a lvt-a topology with the point symbol of {4.8.10}. In addition, the catalytic activity of compound 1 was investigated in the CO2 conversion into cyclic carbonates. It was found that compound 1 was an active catalyst even at low catalyst loading under 0.1 MPa CO2 at 80 °C. The yields of 23–99% were obtained. Compound 1 can be recycled at least four times without significant compromise in the activity in the first three catalytic reactions. [ABSTRACT FROM AUTHOR]

The development of convenient and practical synthetic strategies for constructing bioactive molecules without metal residues is of great interest in organic synthesis. Herein, a metal-free, operationally simple, and scalable electrooxidation-induced three-component cross-coupling method to access 3-thio/selenophosphorylated imidazole derivatives from readily available isothiocyanates/isoselenocyanates, isocyanates, and H-phosphonates is first reported. More than 30 examples have been provided with good to moderate yields. Importantly, the readily accessible compounds could be used as pesticides (wheat anti-locust) with good biocompatibility (5d-stimulated RAW 264.7 macrophages, IL-6 = 5.3 pg mL−1, THF-α = 79.8 pg mL−1), reiterating the importance of the developed electrochemical methodology. [ABSTRACT FROM AUTHOR]

The merging of fundamentally and biologically important heterocyclic structures, such as pyrroles, indoles, and imidazoles, in molecules of dihydropyrrolo[1′,2′:3,4]imidazo[1,2-a]indoles functionalized by E-acylethenyl groups was achieved in water on the platform of commercial 3H-indoles using readily available acylpyrrolylacetylenes as additional building blocks. The yields of the ensembles reached 88% (100 °C, 8 h), which is noticeably better than that produced using conventional solvents (MeCN, MeNO2, DMSO, and CF3CH2OH), wherein the reaction proceeds at a rate of approximately 10 times longer (96 h) with lower yields of the target products (not higher than 80%). The reaction presumably proceeds in a micellar-like microreactor self-assembled in a two-phase aqueous medium that secures favorable mutual orientation of the merging molecules, providing a facile [2+3] concerted cycloaddition to finally form fused polyheterocyclic systems. The performed DFT calculations are in agreement with such mechanistic considerations, particularly those underlying the crucial role of water in the studied cascade process. [ABSTRACT FROM AUTHOR]

Two new bis-ferrocene (Fc) conjugated Y-shaped imidazole (IM) based donor–π–acceptor [(D–π)2–IM–π–A] type "push–pull" compounds [(Fc–CH＝CH)2–IM–C8H17–C6H4–R] {R = COOC2H5 (1); COOH (2)} have been synthesized for second-order nonlinear optics (1, ester) and dye-sensitized solar cell (2, acid) applications. The redox potentials of the compounds were examined using cyclic voltammetry, which shows one-electron charge transfer from the ferrocene to ferrocenium ion (Fe2+ Fe3+), and these potentials were employed to calculate the related energy gap. The second-order nonlinear optical (NLO) properties of the ester compound 1 were explored using the Electric-Field-Induced Second Harmonic generation (EFISH) technique in CHCl3 solution with an incident wavelength of 1907 nm, and it shows an interesting μβEFISH value of −780 × 10−48 esu. Besides, the carboxylic acid compound 2, adequately functionalized for anchoring to TiO2, was tested as a photosensitizer in dye-sensitized solar cells (DSSCs) with non-corrosive Cu(I)/Cu(II) complexes as the redox mediator. Although the photovoltaic performance of 2 attached to TiO2 in a DSSC device is rather limited (JSC = 1.51 mA cm−2, VOC = 404 mV, FF = 42.7, η = 0.26%), it confirms the potential of ferrocenyl conjugated D–π–A systems as photosensitizers. In addition, frontier molecular orbital levels, ground and excited state dipole moments (μg and μe), and the origin of electronic absorption spectra were studied by using density functional theory (DFT) with the B3LYP method using 6-31+G** as the basis set. [ABSTRACT FROM AUTHOR]

The utilization of hexadentate imidazole-derived diamine-bisphenolate ligands to construct structurally well-defined bimetallic nickel catalysts that enable the mediation of the copolymerization of carbon dioxide with alicyclic epoxides was reported for the first time. A series of dinickel carboxylate/nitrophenolate complexes were facilely prepared through a one-pot procedure and their structures were fully determined by single crystal X-ray structural analysis. Dinickel complexes 1–10 were used as single-component catalysts, and were evaluated for the copolymerization of CO2 and cyclohexene oxide (CHO), for which acetato-incorporated complex 1 was proved to exhibit the best activity. Not only has the controllability of binickel catalyst 1 for CO2/CHO copolymerization been demonstrated, but also an "immortal" character for the same polymerization has been realized. Furthermore, detailed kinetic studies of polymerization catalysis of this type were undertaken, and the kinetics results revealed a first-order dependence on both Ni complex 1 and CHO concentrations. This is a successful example of the introduction of the easily accessible nitrogen-heterocycle group, the imidazole moiety, into phenolate ligands for the development of high-performance homogeneous catalysts towards the bimetallic complex-catalyzed copolymerization of CO2 and epoxides. [ABSTRACT FROM AUTHOR]

Barbituric acids are a useful tool for the construction of various supramolecular compounds with intriguing physicochemical properties. Also, barbiturates play a significant role in biology and medicine. The same is true for imidazole derivatives. Herein, three novel salts of barbituric (H2BA) and 2-thiobarbituric (H2TBA) acids with imidazole (Im), namely imidazolium barbiturate in two polymorphic modifications, HIm(HBA) (1) (pale yellow) and (2) (pale orange), and imidazolium 2-thiobarbiturate, HIm(HTBA) (3), were synthesized and characterized by CHNS elemental analysis, single-crystal and powder X-ray diffraction, FT-IR and UV-Vis spectroscopy techniques. Crystal structure analysis revealed that the compounds feature three different supramolecular architectures with the formula unit count (Z′) varying from 1 for 3 to 4 for 1, which is governed by an unusual geometry of hydrogen bonding motifs. Intermolecular interactions in crystals 1–3 were analyzed using 2D-fingerprint plots derived from the Hirshfeld surfaces. According to the TG-DSC analysis, compounds 1–3 were thermally stable up to ∼100 °C in air. The solubility studies (solubility product constants and solubility at a fixed pH value were determined) showed that salts 2 and 3 were more soluble in water than H2(T)BA. To the best of our knowledge, this is one of the first reports on the phenomenon of polymorphism among organic salts with barbiturate moieties. Thus, the present findings broaden our understanding of the supramolecular organization of barbiturates, complement the systematic studies of the correlation between their crystal structure and physicochemical properties and lay the foundation for the further development of novel materials based on imidazolium (2-thio)barbiturates. [ABSTRACT FROM AUTHOR]

Two luminescent Re(I) complexes, namely mononuclear fac-[ReCl(CO)3(TT-Py)] (1) and hexanuclear [{Re(μ-Cl)(CO)3(μ-TT-Py)}{Re2(μ-Cl)2(CO)6}]2 (2), were isolated in high yields by a one-pot reaction between [ReCl(CO)5] and different amounts of nitrogen-rich 2-pyridine cyclic triimidazole (TT-Py), which acts as a chelating ligand in both derivatives. The metallo-supramolecular cyclic structure of 2, which can be described as a metallacycle in which two mononuclear units of 1 act as bridging ligands towards two "Re2(μ-Cl)2(CO)6" fragments, was confirmed by single-crystal X-ray diffraction analysis. Both complexes were fully characterized in solution by 1D and 2D multinuclear NMR spectroscopy. 1 and 2 exhibit photoluminescence at room temperature in solution, with a broad unstructured emission in the 530–570 nm range. The nature of the excited states involved in the electronic absorption spectrum of 1 was ascertained by a combined density functional theory and time-dependent density functional theory (TD-DFT) study. Both compounds exhibit strong aggregation induced emission enhancement (AIEE), which is more pronounced for 2 leading to a solid state photoluminescence quantum yield of 2.5% that is one of the highest values ever reported for Re(I) polynuclear metallacycles so far. The versatility of TT-Py to adopt variegated coordination modes, previously observed for Cu(I) and Cu(II) derivatives, is confirmed supporting further use of this ligand to obtain new and peculiar emissive mono-, polynuclear and extended coordination systems. [ABSTRACT FROM AUTHOR]

The synthesis of a homoleptic azide-functionalised Au(I) bis-1,2,3-triazole-5-ylidene complex is reported, starting from a backbone-modified 1,2,3-triazolium salt ligand precursor. The incorporated azide handle allows for a straightforward modification of the complex according to click-chemistry protocols without impacting the steric shielding around the metal center, demonstrating the superiority of the presented triazole ligand framework over imidazole based systems. Employing the SPAAC and the CuAAC reactions, post-modification of the complex is facilitated with two model substrates, while retaining very high antiproliferative activity (nanomolar range IC50 values) in A2780 and MCF-7 human cancer cells. [ABSTRACT FROM AUTHOR]

Chiral imidazole-based oxidovanadium tartrates (H2im)2[Δ,Λ-VIV2O2(R,R-H2tart)(R,R-tart)(Him)2]·Him (1, H4tart = tartaric acid, Him = imidazole) and [Λ,Λ-VIV2O2(R,R-tart)(Him)6]·4H2O (2) and their corresponding enantiomers (H2im)2[Λ,Δ-VIV2O2(S,S-H2tart)(S,S-tart)(Him)2]·Him (3) and [Δ,Δ-VIV2O2(S,S-tart)(Him)6]·4H2O (4) were obtained in alkaline solutions. Interestingly, the tartrates chelate with vanadium bidentately through α-alkoxy/α-hydroxy and α-carboxy groups and imidazole coordinates monodentately through nitrogen atom. It is worth noting that complexes 1 and 3 contain both protonated α-hydroxy and deprotonated α-alkoxy groups simultaneously, which have short V–Oα-alkoxy distances [1.976(4)av Å in 1–4] and long V–Oα-hydroxy distances [2.237(3)av Å in 1 and 2.230(2)av Å in 3]. There is an interesting strong intramolecular hydrogen bond [O(11)⋯O(1) 2.731(5) Å] between the two parts in 1 and 3. The protonated V–O distances are closer to the average bond distance in reported FeV-cofactors (FeV-cos, V–Oα-alkoxy 2.156av Å) in VFe proteins, which corresponds to the feasible protonation of coordinated α-hydroxy in R-homocitrate in V-nitrogenase, showing the homocitrate in the mechanistic model for nitrogen reduction as a secondary proton donor. Furthermore, vibrational circular dichroism (VCD) and IR spectra of 1–4 pointed out the disparity between the characteristic vibrations of the C–O and C–OH groups clearly. EPR experiment and theoretical calculations support +4 oxidation states for vanadium in 1–4. Solution 13C {¹H} NMR spectra and CV analyses exhibited the solution properties for 1 and 2, respectively, which indicates that there should be a rapid exchange equilibrium between the protonated and deprotonated species in solutions. [ABSTRACT FROM AUTHOR]

The p38 mitogen-activated protein kinase (MAPK) is a crucial target for chronic inflammation. Here, 2D-QSAR and molecular docking studies were performed on a new series of pyridinyl imidazole derivatives as p38α MAPK inhibitors. The goal is to find a correlation between the chemical structures and inhibitory activity of the p38α MAPK. The partial least squares (PLS) regression method was used to build the 2D-QSAR model. The results revealed that the generated model yielded 0.85 for the determination coefficient (r2), 0.83 for the adjusted determination coefficient (ra2), and 0.16 for the root-mean-square error (RMSE). Internal and external validations were used to figure out how well the model could predict the future. The rcv2 and rtest2 values were 0.78 and 0.92, indicating that the developed model is robust and capable of predicting the activity of new compounds. The affinity of the ligands (pyridinyl imidazole derivatives) and the binding pocket of the p38α MAP kinase receptor was also determined by molecular docking using autoDock tools. The results revealed the importance of conventional hydrogen bonds in the binding pocket of the p38α MAPK receptor. Based on these results, a novel series of compounds were predicted and evaluated using molecular dynamics (MD) and ADMET prediction investigations. The study's findings might pave the way for the development of new pyridinyl imidazole derivatives that are able to inhibit the enzymatic activity of the p38α MAP kinase. [ABSTRACT FROM AUTHOR]

Imidazole is an important heterocyclic motif and its derivatives are widely used in many fields such as catalysis, medicine, and smart sensors. Here we report the synthesis of four imidazole derivatives (M1, M2, M3, and M4) with different fused aromatics as fluorescent sensors for picric acid (PA) detection. The four compounds with modifications of triphenylamine or tetraphenylethylene at the N1 and C2 positions of the imidazole ring exhibit typical aggregation-induced emission (AIE) properties. The single crystallography results indicate that the bright luminescence is ascribed to the rigidified molecular conformation by multiple weak interactions. As PA probes, M1–M4 show high selectivity and sensitivity in the tetrahydrofuran/water mixture (fw = 99%). The detection limits are as low as 10−9 M. Mechanism study suggests that photoinduced electron transfer (PET) is responsible for PA detection. These AIE-active imidazole derivatives have been demonstrated to be convenient and easily operating sensors for PA detection. [ABSTRACT FROM AUTHOR]

ZIF-67 is a representative type of metal–organic framework (MOF) developed for the oxygen reduction reaction (ORR) owing to its robust structure in alkaline electrolytes and the presence of the redox-active Co2+ species in the structure. In this work, the improvement of the ORR electrolytic performance of ZIF-67 in its pure phase by optimization of its crystal morphology and crystal facets has been presented. ZIF-67 nanocubes exhibit higher ORR activity than their bulk crystals. The enriched (100) facet in the nanocube crystals provides a higher number of exposed Co2+ sites resulting in improved ORR performances. Moreover, DFT study suggests a distinguished mechanism in the (100) facet highlighting the importance of crystal facets in electrochemical performances. [ABSTRACT FROM AUTHOR]

We designed four ternary lanthanide tris-(β-diketonate) complexes of the form [Ln(tta)3(tpy-HImzphen)], where Ln = LaIII, EuIII, SmIII and TbIII; tta = (2-theonyltrifluoroacetonate) and tpy-HImzphen = 2-(4-[2,2′:6′,2′′]terpyridin-4′-yl-phenyl)-1H-phenanthro[9,10-d]imidazole. All the complexes have been thoroughly characterized by standard analytical tools and spectroscopic techniques including single crystal X-ray diffraction. In situ generation of the complexes was also monitored via absorption and emission spectroscopy upon incremental addition of the respective lanthanide precursor {Ln(tta)3(H2O)2} to the dichloromethane solution of the terpyridyl-imidazole ligand. The photophysical behaviors of all the complexes were thoroughly investigated via absorption and both steady-state and time-resolved emission spectroscopic techniques. The emission spectral measurements were carried out at both room temperature and 77 K to understand the deactivation dynamics of the excited states and elucidate the distinctive luminescence responses from the four lanthanide metal ions owing to the introduction of the terpyridyl-based ancillary ligand. [ABSTRACT FROM AUTHOR]

Design of metal–organic frameworks (MOFs) with elaborate structural features is of great significance for their applications with improved performances. In this work, we report the construction of unique zinc-based zeolite imidazole framework (ZIF-8) microrings via an anisotropic growth-etching route. The synthesis relies on the anisotropic deposition of ZIF-8 crystals on the edges with coordinatively unsaturated Zn2+ of leaf-like ZIF (ZIF-L) nanosheets and subsequent selective etching of alkaline unstable ZIF-L. Furthermore, functional carbon materials with a ring-like structure can be prepared by pyrolysis of ZIF-8 microrings as precursors, exhibiting enhanced oxygen reduction reaction performance compared to the traditional ZIF-8 derived counterparts. Our work may pave the way for the design of MOFs with sophisticated micro/nanostructures. [ABSTRACT FROM AUTHOR]

The zeolitic imidazole framework with a leaf-shaped morphology (ZIF-L) has a wide range of promising applications in gas storage, battery materials, catalytic reactions, and optoelectronic devices due to its planar leaf-like structure and large surface area. However, the low conductivity, weak catalytic activity, and poor stability in the water dielectric medium of ZIF-L limit its further practical application. To solve these problems, we added the conductive polymer heterocyclic poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to ZIF-L for the sensitive detection of dopamine (DA). The synthesized composite ZIF-L/PEDOT:PSS (ZIF-L/PEDOT) not only retained the surface morphology of ZIF-L but also exhibited excellent electrochemical properties. The higher electrical conductivity of ZIF-L/PEDOT than that of ZIF-L was due to the enhanced electron transfer at the interface between ZIF-L and PEDOT:PSS. As a result, we developed an electrochemical biosensor based on the ZIF-L/PEDOT composite, which has a limit of detection of 7 nM for DA and a wide linear range from 25 nM to 500 μM. Furthermore, the current drop was negligible after 28 days, proving that the biosensor has excellent stability. Based on the above-mentioned outstanding performance, the ZIF-L/PEDOT-based biosensor was successfully used to detect DA in human serum samples. These results demonstrated that ZIF-L/PEDOT is expected to play an essential role in disease detection. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are battery-type supercapacitor electrode materials with application potential due to their abundant active metal sites and surface functional groups. The traditional LDH structure easily aggregates and collapses. In this work, a stable cobalt zeolite imidazole framework (Co-ZIF) was used as the derived template to grow LDH nanosheets in situ to increase the contact area with the electrolyte, and polyaniline (PANI) acted as a conductive bridge to provide a rapid charge transfer pathway. The fabricated NiCo-LDH@PANI hollow structure demonstrated a specific capacity of 1315 C g−1 at 1 A g−1 and achieved a rate capacity of 951 C g−1 at 20 A g−1. Furthermore, the battery–supercapacitor hybrid device (NiCo-LDH@PANI//AC) exhibited an high energy density of 66.2 W h kg−1 at a power density of 800 W kg−1 with 95.5% capacitance retention after 20 000 cycles. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are composed of metal ions and organic ligands with high specific surface areas, controllable porous structures and abundant metal active sites, showing their extraordinary potential in electrochemical sensors. Here, a 3D conductive network structure (C–Co–N@MWCNTs) is designed by anchoring zeolite imidazole frameworks (ZIF-67) onto multi-walled carbon nanotubes (MWCNTs) and carbonizing them. The C–Co–N@MWCNTs exhibit excellent electron conductivity, a porous structure and considerable electrochemical active sites, which can effectively demonstrate high sensitivity and selectivity in the detection of adrenaline (Ad). The Ad sensor exhibited a low detection limit of 6.7 nmol L−1 (S/N = 3) and a wide linear range of 0.02 μmol L−1–1.0 mmol L−1. The developed sensor also displayed high selectivity, good reproducibility and repeatability. The C–Co–N@MWCNTs electrode was further employed in the detection of Ad in a real sample of human serum, suggesting that it is a promising candidate for electrochemical sensing of Ad. [ABSTRACT FROM AUTHOR]

We describe the synthesis of a symmetrical N,N′-bis(3-(1H-imidazol-1-yl)propyl)oxalamide-based receptor OX(PID)2 and its characterization by different physicochemical techniques, namely FT-IR, 1H and 13C NMR, TGA, and mass spectrometry. Single crystal X-ray diffraction analysis shows that OX(PID)2 crystallizes in monoclinic space group P21/c. The sensing capability of OX(PID)2 towards various cations has been exhaustively investigated using UV-vis and fluorescence spectroscopy. OX(PID)2 shows high selectivity and sensitivity towards Cu2+ and Fe3+ ions with a 1 : 1 binding ratio over other metal ions, which was highly supported via Job's plot and density functional theory calculations. The Cu2+ and Fe3+ ions induce the 'turn-off' signal when interacting with OX(PID)2. Moreover, using four different bacterial species, including S. aureus, B. subtilis, E. coli, and K. pneumonia, the biological activities of the newly created oxalamide-based compounds were assessed against various pathogenic bacteria and compared to streptomycin as a reference drug. Our substances exhibit moderate to good vital action against the aforementioned harmful microorganisms, according to the results. Then, fluorescence imaging in MDA-MB-231 on receptor OX(PID)2 suggested that OX(PID)2 had great potential in the application of bioimaging. The receptor with Cu2+ or Fe3+ ions was found to be cytotoxic against MDA-MB-231 and could be used as an anticancer agent. [ABSTRACT FROM AUTHOR]

Herein, we have realized an efficient and solvent-tunable Rh(III)-catalyzed [5+2] annulation of N-benzo[d]imidazole indolines with 2,2-difluorovinyl tosylate that presented an unusual 1,2-regioselectivity for the chemodivergent construction of monofluorinated and gem-difluorinated benzodiazepines, which are defined as potent anti-tumor agents against different cancer cell lines. In general, this work provides a powerful complement to both C–H activation chemistry and anti-tumor lead discovery. [ABSTRACT FROM AUTHOR]

Neural network and decision tree-based soft computing techniques are implemented in this work for the thorough analysis of the multichannel anion-sensing characteristics of an Os(II)-bipyridine complex derived from imidazole-4,5-bis(benzimidazole) ligand. With the aid of three imidazole NH protons in its outer coordination sphere, a substantial change in the spectral response as well as OsII/OsIII potential is made possible upon treating with anions of varying basicity. Initial hydrogen bonding between NH protons and anions and thereafter complete proton transfer from the complex backbone probably take place in the process. The deprotonation of the complex by specific anions and restoration to its original form by acid is also reversible. The responsiveness of the new compound is complex enough to imitate multiple sophisticated binary and ternary Boolean logic (BL) functions (NOT logic, combinational logic, traffic signal, set-reset flip-flop logic, and ternary NOR logic) by employing its spectral and redox outputs upon the action of suitable anions and acid in a proper sequence. Executing sensing investigations on altering the amount of the anions within a widespread range is often time-consuming and tedious. To overcome the lacuna, we implemented multiple soft computing techniques, viz., fuzzy logic (FL), artificial neural networks (ANNs), adaptive neuro-fuzzy inference system (ANFIS), and decision tree (DT) regression, for the thorough analysis and prediction of the experimentally observed results. The outcomes obtained from different techniques were compared among themselves as well as with the experimental data and utilized for the proper modeling of the anion-sensing behaviors of the complex. [ABSTRACT FROM AUTHOR]

The simultaneous achievement of large surface areas and high IL contents in porous materials are highly beneficial for efficient carbon dioxide (CO2) capture and atmospheric fixation. Herein, a series of porous hypercrosslinked poly(ionic liquid)s (HPILs) are successfully developed through a two-step synthetic strategy, including free radical self-polymerization of a specific benzyl bromide-tethered imidazole ionic liquid (IL) to fabricate a linear PIL as a precursor, and a subsequent Friedel–Crafts alkylation between the precursor and the crosslinker for hypercrosslinking. The HPILs featured large surface areas of up to 855 m2 g−1 along with a hierarchically nanoporous structure, high IL contents (2.19–2.91 mmol g−1) and satisfactory CO2-philic properties. By virtue of the combined advantages, HPILs served as metal-free heterogeneous catalysts for solvent-additive-free CO2 cycloaddition with epichlorohydrin at 80 °C and 0.1 MPa CO2 for 24 h, presenting high catalytic activity and stable reusability. A high yield of 99.0% coupled with a turnover frequency (TOF) of 6.0 h−1 was achieved, much higher than most of the reported metal-free heterogeneous catalysts, even superior to homogeneous analogues. Furthermore, various epoxides, including large-sized epoxides, were effectively converted into carbonates with high yields, affording good substrate applicability. This work reports a facile and universal approach for the construction of porous HPILs with both great porosities and high IL contents towards efficient chemical fixation of CO2 under mild conditions. [ABSTRACT FROM AUTHOR]

Nitrosyl ruthenium complexes are promising platforms for nitric oxide (NO) and nitroxyl (HNO) release, which exert their therapeutic application. In this context, we developed two polypyridinic compounds with the general formula cis-[Ru(NO)(bpy)2(L)]n+, where L is an imidazole derivative. These species were characterized by spectroscopic and electrochemical techniques, including XANES/EXAFS experiments, and further supported by DFT calculations. Interestingly, assays using selective probes evidenced that both complexes can release HNO on reaction with thiols. This finding was biologically validated by HIF-1α detection. The latter protein is related to angiogenesis and inflammation processes under hypoxic conditions, which is selectively destabilized by nitroxyl. These metal complexes also presented vasodilating properties using isolated rat aorta rings and demonstrated antioxidant properties in free radical scavenging experiments. Based on these results, the new nitrosyl ruthenium compounds showed promising characteristics as potential therapeutic agents for the treatment of cardiovascular conditions such as atherosclerosis, deserving further investigation. [ABSTRACT FROM AUTHOR]

Bio-compatible water-soluble conjugates of Co(II), Cu(II) and Zn(II) (1–3), [Co(Boc- L -valine)2(imidazole)2], [Cu(Boc- L -valine)2(imidazole)2], and [Zn(Boc- L -valine)2(imidazole)2], were synthesized and comprehensively characterized by various spectroscopic techniques (UV–visible, FT-IR, ESI-MS, EPR, 1H NMR, 13C NMR) and single crystal X-ray diffraction which showed that the complexes 1–3 crystallized in an orthorhombic crystal system, in a slightly distorted octahedral geometry having the space group P21212. Density functional theory calculations were performed to correlate the energy of frontier molecular orbitals with the stability and reactivity of the complexes. In vitro DNA binding interaction studies of complexes were performed by employing various biophysical techniques and their corroborative results revealed (i) the electrostatic mode of binding in the groove region of DNA, (ii) pBR322 plasmid cleavage at a low concentration of 5–12.5 μM via an oxidative pathway in complexes 1 and 2 and the hydrolytic mechanism in the case of 3, (iii) changes in the 1H NMR chemical shift values of the NH2 group of GMP after interaction with complex 3, (iv) alteration in the EPR parameters of complex 2 after complexation with DNA, (v) SOD mimetic activity of complex 2 with the IC50 value of 2.08 μM and (vi) a good and selective cytotoxicity profile against chemo-resistant MCF-7 and MDA–MB–231 cancer cell lines by complex 1. Molecular docking studies complemented the spectroscopic results and confirmed the electrostatic interaction of complexes in the groove region of DNA. [ABSTRACT FROM AUTHOR]

In this study, flower-like porous iron doped bismuth oxybromide on porous activated carbon visible light catalysts (BiOBr/Fe@AC) were prepared by a reactive imidazole ionic liquid surfactant assisted solvothermal process. The morphologies, structures, optical properties and photocatalytic properties were investigated in detail. The morphology of the synthesized Fe doped BiOBr composites gradually changed from a regular spherical shape to a non-specific shape with the increase of the alkyl chain length of the ionic liquid surfactants. The photocurrent of BiOBr/Fe@AC composites is greatly influenced by the content of Fe, the type of carbon sphere and the size of the composites. The photocatalytic activity of the obtained BiOBr/Fe@AC composites was evaluated by the degradation of 2-chloroethyl sulfide (CEES) under visible light. The BiOBr/Fe@AC composites exhibited significantly enhanced photocatalytic performance compared to that of pure BiOBr and the 10.0% Fe doped BiOBr/Fe@AC composite displayed the highest photocatalytic activity. The main active species were determined to be holes and superoxide radicals by electron spin resonance (ESR) analysis and free radical trapping experiments. The introduction of iron can improve the separation and transfer rate of photoinduced charges. Carbon spheres can enhance light harvesting, improve electron transfer and increase the number of catalytic active sites. Iron and carbon embellishment is an effective strategy to enhance the photocatalytic efficiency of BiOBr. Finally, a possible photocatalytic mechanism of BiOBr/Fe@AC has been proposed. [ABSTRACT FROM AUTHOR]

Many studies have been focused on the selective separation of hydrogen chloride (HCl) gas, but its capture and conversion in situ is still at a standstill. Herein, a pioneering attempt to employ a deep eutectic solvent (DES) as a "courier" to combine HCl capture and in situ conversion has been presented. Impressively, the highest HCl absorption capacity is determined to be 3.95 mol/mol, or 0.672 g/g, or 18.4 mol kg-1 at 1.0 bar and 30 °C in a binary DES based on EmimCl/Im. The internal transmission mechanism between imidazole and HCl was revealed by DFT-based theoretical calculations. The reaction between HCl and epoxides achieved 99% conversion under mild conditions in the absence of a solvent, making the entire reaction ecologically benign. Water extraction was used to recycle the DES from the reaction system, and it maintained good catalytic performance after ten cycles. The exhaust HCl-SO2 mixed gases from the sucralose industry were further investigated, which proved the possibility of selective conversion of HCl. Furthermore, a plausible reaction-separation-integration (RSI) strategy was proposed to avoid the high energy consumption of desorption, which provides a novel insight into future applications. It is believed that the good results, combined with the simplicity of operation and the high recyclability of the catalyst, make this green method environmentally friendly and cost-effective. This work reveals an effective approach for the coupling of HCl capture and conversion under mild conditions. [ABSTRACT FROM AUTHOR]

In this study, zeolitic imidazole framework-8/cellulose membrane (ZIF-8/CM) was fabricated through an in situ synthesis method. The composite was installed in a dismountable filter and used as a sorbent for lab-made microextraction in packed syringe (MEPS). The entire MEPS procedure can be performed through simple operation of filtration, since the macroporous cellulose membrane was introduced as the substrate for ZIF-8 powder. Coupled to a high performance liquid chromatography tandem ultraviolet detector (HPLC-UV), the proposed method was applied for the analysis of tetracyclines in water samples. The extraction parameters, including the adsorbent type, sample solution pH, sample volume, type and volume of the elution solvent, were systematically studied. Under optimized conditions, desirable linearity (r > 0.99 for three analytes), high sensitivity (limit of detection: 0.1373–0.8917 μg L−1), good precision (RSD < 6.3%) and ideal recovery (72.9–97.6%) were obtained. The proposed method was demonstrated to be efficient, easily operative and environmentally friendly. [ABSTRACT FROM AUTHOR]

A novel metal complex redox material is synthesized via coordinating the iron metal site with 1-(naphthalen-2-ylmethyl)-2-(pyridin-2-yl)-1H-benzo[d]imidazole (npbi) ligands, herein named as Fe2+/3+ [npbi]3. The as-synthesized Fe2+/3+ [npbi]3 redox material has a good redox potential (0.43 V vs. NHE), low Gibbs free energy (1.86 eV), low reorganization energy (1.90 eV), high diffusion coefficient and less driving force in an electrolyte system for dye sensitized solar cell (DSC) and supercapacitor (SC) applications to accomplish huge quasi-reversible redox operations between the electrode/electrolyte interfaces of the devices. Interestingly, the DSC with the Fe2+/3+ [npbi]3 electrolyte and an organic dye achieved a conversion efficiency of 2.96% under 1 sun illumination. This high power efficiency is attributed to a potential matching of this redox system with the organic dye, which can diminish the recombination reactions and improve the open circuit voltage (OCV) of the DSC. At the same time, the addition of Fe2+/3+ [npbi]3 in a symmetric SC with a H2SO4 electrolyte and graphene oxide electrodes contributes to an additional Faradaic reaction (electro-sorb mechanism) at the electrode/electrolyte interface. This results in the corresponding SC displaying a high energy density of 29.79 W h kg−1 at a power density of 719 W kg−1 and long charge/discharge stability for 11 000 cycles with 97.4% capacity retention respectively. Overall, this study offers new insights on designing appropriate transition metal complex redox materials for both DSC and SC applications with boosted efficiencies. [ABSTRACT FROM AUTHOR]

A series of N1-functionalized imidazoles have been synthesized in very good yield. Due to their amphoteric nature, they selectively discriminate among different nitroaromatic compounds. The fluorescence spectra of all the luminophores are highly sensitive towards picric acid compared to other nitroaromatic compounds. The fluorescence method has a fast response, low cost, and high selectivity for picric acid over other nitroaromatic compounds. Electrochemical analysis was performed and verified using DFT calculations. The electrochemical properties were studied using cyclic voltammetry to calculate the HOMO–LUMO gap, and were also confirmed via theoretical study. The Stern–Volmer quenching constant and detection limit were found to be 6.68 × 106 M−1 and 446 ppb. The capability of luminophores to recognise picric acid was estimated using fluorescence, DFT analysis, and 1H NMR spectroscopy. Thus, potential luminophores were synthesized as convenient and promising multifunctional sensors for toxic and explosive nitroaromatic analytes. [ABSTRACT FROM AUTHOR]

Achieving deep blue thermally activated delayed fluorescent (TADF) materials with narrow emission still remains a challenge. Herein, two deep blue TADF emitters DCBTRZ and PPCTRZ were designed and synthesized by directly using host materials, 1,4-di(carbazol-9-yl)benzene (DCB) and 2-[4-(9H-carbazol-9-yl)phenyl]-1-phenyl-1H-phenanthro[9,10-d]imidazole (PPC) as donors, and 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. The two emitters have typical TADF properties. Both of them can emit deep blue fluorescence with a very narrow full-width at half-maximum (FWHM) of 42 nm in toluene. The photoluminescence quantum yields (PLQYs) of DCBTRZ and PPCTRZ are 39.6% and 38.2% in doped films, respectively. Devices based on DCBTRZ and PPCTRZ achieve deep blue emission (440 and 442 nm) with maximum external quantum efficiencies (EQEmax) of 6.68% and 6.55%, respectively. Meanwhile, they exhibit very high color purity. The CIEy and FWHM of devices employing DCBTRZ and PPCTRZ are 0.059/0.063 and 56/54 nm, respectively, meeting the standard of NTSC for deep-blue emitters, which indicates excellent application prospects in displays. The results suggest that this strategy for developing deep blue TADF materials with narrow emission and CIEy < 0.06 directly employing host materials as donors is feasible and effective. [ABSTRACT FROM AUTHOR]

The aim of this study has been to offer a method for the synthesis of 2,4,5-trisubstituted imidazole derivatives based on green chemistry principles. Therefore, a one-pot multicomponent cyclocondensation reaction through aldehyde interaction with ammonium acetate and 1,2-diketone under solvent-free conditions was utilized as an eco-effective synthetic route using CoFe2O4@SiO2@(–CH2)3OWO3H NPs as the catalyst. The stabilized tungstic acid on 3-chloropropyl-anchored SiO2-coated CoFe2O4 magnetic nanoparticles was designed, prepared, and applied as a recyclable heterogeneous acid catalyst to attain high product yield in a short reaction time. The nanocatalyst structure was confirmed using FT-IR, Raman, XRD, FE-SEM, EDX, VSM, and TGA techniques, and the organic product structures were examined by melting point, FT-IR and 1H NMR analyses. [ABSTRACT FROM AUTHOR]

A new family of well-defined and fully conjugated oligoelectrolyte compounds were elaborated based on one or two bis-thiophene dialkoxyphenylene units. Di- or tetra-functionalized compounds with imidazolium, pyridinium and triethylammonium cationic species were synthesized in good yields. The effect of counteranions was also evaluated using iodide, chloride, fluoride and hexafluorophosphate anions. Their solubility was measured in apolar solvents (cyclohexane and chloroform) and polar protic solvents (water, ethanol, and isopropanol). A study of their thermal properties was conducted with TGA analysis showing a good stability up to 220 °C. Furthermore, their optical properties were examined and similar absorption properties were observed in solution and in the solid state. Most of these compounds exhibited significant fluorescence properties which were dependent on their involved counteranion and the solvent used. [ABSTRACT FROM AUTHOR]

It is necessary to recover precious metals from aqueous solutions because they have a wide range of applications. In this work, a poly(ionic liquid) (PIL) gel containing an imidazole group was fabricated using a radiation method and utilized for the capture of Au(III), Pt(IV), and Pd(II) ions. It was discovered that the PIL gel exhibited high adsorption efficiency for Au(III), Pt(IV), and Pd(II) in a wide pH range. The adsorption processes for target ions all reached equilibrium within 4 min. Meanwhile, the isotherm experiments revealed that the adsorption was in accordance with the Langmuir model, and the maximum adsorption capacities were 854.7 mg g−1 for Au(III), 420.2 mg g−1 for Pt(IV), and 277.8 mg g−1 for Pd(II). Furthermore, the PIL gel could selectively adsorb Au(III), Pt(IV), and Pd(II) from simulated acidic waste effluent containing Cu(II), Zn(II), Fe(III), and Ni(II). In particular, the PIL gel demonstrated its ability to selectively recover trace Au(III) from real gold slag leaching solution. FTIR and XPS analyses revealed that anion exchange was the dominant adsorption mechanism. [ABSTRACT FROM AUTHOR]