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Design of material showing contraction upon heating is highly challenging due to varying mechanism. However, imidazole is found to be a potential molecule that may provide low CTE materials when incorporated in the matrix. Here we have reported thermal expansion property of imidazolium salts of five aliphatic α, ω‐alkane dicarboxylic acids and three aromatic acids. Either uniaxial or biaxial negative thermal expansion (NTE) has been observed in most of the salts. In some cases, axial zero thermal expansion (ZTE) has been observed. The role of imidazolium moiety for the anomalous thermal expansion behaviour of the salts has been analyzed in this study. The controlled TE behaviour of the salts is attributed to the hydrogen bonding and transverse vibration in all imidazolium salts. Owing to the high transverse vibration observed in imidazolium ion as well as the heavier oxygen atoms of acids in each case, the distance between hydrogen bonded atoms decreases–which provides either low expansion or contraction along one of the principal axes. [ABSTRACT FROM AUTHOR]

N,N′‐Diarylimidazolium salts containing haloalkyl functional groups that are reactive with various nucleophiles are considered to be promising reagents for the preparation of functionalized N‐heterocyclic carbene (NHC) ligands, which are in demand in catalysis, materials science, and biomedical research. Recently, 4‐chloromethyl‐functionalized N,N′‐diarylimidazolium salts became readily available via the condensation of N,N′‐diaryl‐2‐methyl‐1,4‐diaza‐1,3‐butadienes with ethyl orthoformate and Me3SiCl, but these compounds were found to have insufficient reactivity in reactions with many nucleophiles. These chloromethyl salts were studied as precursors in the synthesis of bromo‐ and iodomethyl‐functionalized imidazolium salts by halide anion exchange. The 4‐ICH2‐functionalized products were found to be unstable, whereas a series of novel 4‐bromomethyl functionalized N,N′‐diarylimidazolium salts were obtained in good yields. These bromomethyl‐functionalized imidazolium salts were found to be significantly more reactive towards various N, O and S nucleophiles than the chloromethyl counterparts and enabled the preparation of previously inaccessible heteroatom‐functionalized imidazolium salts, some of which were successfully used as NHC proligands in the preparation of Pd/NHC and Au/NHC complexes. [ABSTRACT FROM AUTHOR]

A new heterocyclic compound, 2-(2,6-diisopropylphenyl)-1-methylimidazo[1,5-a]quinolin-2-ium tetrafluoroborate 1 was obtained from its precursor, N-(2,6-diisopropylphenyl)-N-(quinolin-2-ylmethyl)acetamide 2, by POCl3-mediated cyclization. For the first time, tertiary acetamide 2, the precursor of 1, was synthesized by using commercially available starting materials. The structure of 1 was unquestionably confirmed by 1H, 13C, 2D-NMR, and IR spectroscopies and mass spectrometry. Its optical properties were also studied. [ABSTRACT FROM AUTHOR]

[Display omitted] A new method for encapsulating cationic glycerolipids is proposed, based on their use as templating agents in the sol–gel synthesis of mesoporous silica particles. Using the example of rac - N -{4-[(2-ethoxy-3-octadecyloxyprop-1-yl)-oxycarbonyl]butyl}- N' -methylimidazolium iodide, it is shown that this method results in the formation of high-capacity container particles with a pronounced porous structure and a narrow size distribution. [ABSTRACT FROM AUTHOR]

This work presents the synthesis and characterization of mono‐ (1) and di‐nuclear (2) imidazolium salts stabilized by [AuPPh3]+ fragments. The presence of the gold moiety induces a significant decrease in the carbenic proton's acidic character (high pKa). This high stability is consistent with the pronounced instability of the conjugate bases obtained through deprotonation using strong bases. The formation of carbene species is accompanied by the identification of a 1,2‐rearrangement process in which a preference for the C‐bound species over the N‐bound species is observed. Experimental techniques such as NMR, single‐crystal X‐ray diffraction analysis, mass spectrometry, and computational calculations are employed to investigate the reactivity exhibited by the imidazolium salts. Additionally, the electrochemical properties of the two imidazolium salts were also investigated. This study reveals that both species 1 and 2 display two cathodic peaks which are related to two electro‐chemical irreversible reduction events. The results obtained from both experimental and theoretical studies of this system reveal a strong tendency of the [AuPPh3]+ fragment to stabilize imidazolium salts. Additionally, they demonstrate the preference of this fragment for C‐bound species over N‐bound ones, with the former proving to be highly unstable even under severe conditions of air and moisture exclusion. [ABSTRACT FROM AUTHOR]

The reaction of readily available N,N′-diaryl-4-chloromethylimidazolium chlorides with thiols afforded 4-(alkyl)arylsulfanylmethyl-N,N′-diarylimidazolium salts. The oxidation of these salts with hydrogen peroxide catalyzed by ammonium paramolybdate gave the previously unknown 4-(alkyl)arylsulfonylmethyl-N,N′-diarylimidazolium salts. The synthesized imidazolium salts can be used as sources of N-heterocyclic carbenes (NHCs). The conditions were found for the selective palladation of these compounds involving the C(2) atom of the imidazole ring. Palladium complexes with NHC ligands functionalized with RSCH2 and RSO2CH2 groups were synthesized. The potential applicability of these complexes as catalysts for cross-coupling reactions was demonstrated. [ABSTRACT FROM AUTHOR]

A new heterocyclic compound, 2-(2,6-diisopropylphenyl)-1-methylimidazo[1,5-a]quinolin-2-ium tetrafluoroborate 1 was obtained from its precursor, N-(2,6-diisopropylphenyl)-N-(quinolin-2-ylmethyl)acetamide 2, by POCl3-mediated cyclization. For the first time, tertiary acetamide 2, the precursor of 1, was synthesized by using commercially available starting materials. The structure of 1 was unquestionably confirmed by 1H, 13C, 2D-NMR, and IR spectroscopies and mass spectrometry. Its optical properties were also studied.

New imidazolium salts with 1,2,3-triazole rings (rm1-rm5) were prepared in the current work using a design-driven synthetic procedure scheme. By using analytical techniques such as NMR, IR and spectral information, the chemical structures of target synthesized products were identified using results that were discovered in perfect accord with their assigned structures. The microorganism used in the current study were bacterial strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis and Micrococcus luteus, as well as the fungal strains of Aspergillus niger and Candida albicans. All the end products were estimated for their antibacterial activity. The values for the minimum inhibitory concentration (MIC) were confirmed by comparison to the widely used antibiotics fluconazole and ciprofloxacin as control drugs. Particularly, the compounds (rm5) and (rm4) showed observable antibacterial activity. These compounds might offer a brand-new place to start when looking for new antibacterial medications.

A new study focused on the synthesis of silver(I)‐N‐heterocyclic carbene complexes. The mono‐Ag(I)‐NHC complexes were successfully synthesized in high yield using a direct complexation method, which involved an excess of Ag2O and imidazolium salts (R= butyl, methylacetate) in dichloromethane. The bis‐Ag(I)‐NHC complexes, on the other hand, were synthesized using a 1 : 2 ratio of Ag2O and imidazolium salts. The ligands and resulting complexes were thoroughly characterized using analytical techniques such as FT‐IR, NMR spectroscopy, LC–MS and elemental analysis. Subsequently, the synthesized complexes were tested against MCF7 breast cancer cells. The results of the study highlighted the remarkable anticancer potential exhibited by the Ag(I)‐NHC complexes against breast cancer cells. Interestingly, it was observed that the mono Ag(I) NHC complexes demonstrated greater potency, with IC50 values ranging from 5 to 13.5 μg/mL, when compared to their bis‐Ag(I)‐NHC counterparts. [ABSTRACT FROM AUTHOR]

The hole‐transporting material (HTM) in perovskite solar cells (PSCs) provides an ideal interface with the perovskite layer for hole collection while influencing the perovskite crystalline structure and morphology. This article presents SIM and DIM, two new dopant‐free imidazolium‐based HTMs with charged units accompanied by counter ions that show the potential to function as ionic HTMs and ionic liquid additives and help improve the efficiency and stability of inverted PSCs. DIM‐based PSCs demonstrates exceptional performance with a high‐power conversion efficiency of 19.15%, attributed to improved passivation of perovskite interface defects. Furthermore, these new imidazolium salt‐based HTMs can be manufactured economically, making them a viable option for mass production and PSC commercialization. [ABSTRACT FROM AUTHOR]

Low transition temperature mixtures (LTTMs) are a new generation of solvents that have found extensive application in organic synthesis. The interactions between the components often generate highly activated, catalytically active species, thus opening the possibility of using LTTMs as catalysts, rather than solvents. In this work, we introduce a nickel-based imidazolium LTTM, study its thermal behavior and explore its catalytic activity in the solvent-free allylation of heterocycles with allylic alcohols. This system is effective in this reaction, affording the corresponding products in excellent yield without the need for additional purifications, thus resulting in a very environmentally friendly protocol. [ABSTRACT FROM AUTHOR]

A series of cationic p-tert-butylcalix[4]arenes, with side-arms that are functionalized with imidazolium groups, have been synthesized in good yields. The parent tetrahydroxy para-t-butyl-calix[4]arene was dialkylated at the phenolic hydrogen atoms using α,ω-dibromo-alkanes to yield bis(mono-brominated) alkoxy-chains of variable length. The brominated side-arms in these compounds were then further alkylated with substituted imidazoles (N-methylimidazole, N-(2,4,6-trimethyl-phenyl)imidazole, or N-(2,6-di-isopropylphenyl)imidazole) to yield a series of dicationic calixarenes with two imidazolium groups tethered, via different numbers of methylene spacers (n = 2–4), to the calixarene moiety. Related tetracationic compounds, which contain four imidazolium units linked to the calix[4]arene backbone, were also prepared. In all of these compounds, the NMR data show that the calixarenes adopted a cone configuration. All molecules were characterized by NMR spectroscopy and by MS studies. Single crystal X-ray diffraction studies were attempted on many mono-crystals of these cations, but significant disorder problems, partly caused by occluded solvent in the lattice, and lack of crystallinity resulting from partial solvent loss, precluded the good resolution of most X-ray structures. Eventually, good structural data were obtained from an unusually disordered single crystal of 5a, (1,3)-Cone-5,11,17,23-tetra-t-butyl-25,27-di-hydroxy-26,28-di-[2-(N-2,6-diisopropylphenyl-imidazolium)ethoxy]calix[4]arene dibromide and its presumed structure was confirmed. The structure revealed the presence of H-bonded interactions and some evidence of π-stacking. Some of these imidazolium salts were reacted with nickelocene to form the nickel N-heterocyclic carbene (NHC) complexes 7a–7d. A bis-carbene nickel complex 8 was also isolated and its structure was established by single crystal X-ray diffraction studies. The structure was disordered and not of high quality, but the structural data corroborated the spectroscopic data. [ABSTRACT FROM AUTHOR]

An efficient protocol for the C−N cross‐coupling of aryl chlorides with (hetero)aryl‐ and alkyl amines under nickel catalysis has been developed. The main advantage of the protocol is the use of a self‐activated Ni/NHC catalytic system generated in situ from readily available bench‐stable air‐tolerant precursors: NiCl2Py2, IPr ⋅ HCl, and sodium tert‐butoxide. A mass spectrometry mechanistic study of the reaction system revealed the dynamics of competitive processes of Ni/NHC active species formation and degradation involving NHC reductive elimination reactions and tert‐butoxide base. Optimization of the NiCl2Py2/IPr ⋅ HCl/tBuONa ratio and the reaction temperature allowed efficient catalysis to be achieved. The developed simple protocol represents an alternative for methods relying on the use of air‐sensitive and unstable Ni(cod)2 or expensive well‐defined Ni/NHC precatalysts. [ABSTRACT FROM AUTHOR]

Carbohydrate‐based imidazolium salts (IMSs) are structural patterns for the synthesis of pharmaceutically and biologically active substances. For this purpose, the chiral furanoside‐based imidazolium salt conjugated with a cysteamine (Cyt) linker attached gold and silver nanoparticles were prepared in this study. The biological applications of the HeLa and A549 cell lines using MTT cell proliferation method were exhibited to determine the biological evaluation of NPs conjugated with sugar based imidazolium salt. The satisfactory results obtained demonstrated that the synthesized glyconanoconjugates were radiotherapeutic agents. Moreover, this modification type within a galactose derived imidazolium salt is the first work in bioapplications, especially in radiotherapy. The antimicrobial activity of IMSs and their nanoconjugates against test pathogens was also evaluated using the disc diffusion technique. [ABSTRACT FROM AUTHOR]

Three series of podophyllotoxin derivatives with various nitrogen-containing heterocycles were designed and synthesized. The antitumor activity of these podophyllotoxin derivatives was evaluated in vitro against a panel of human tumor cell lines. The results showed that podophyllotoxin-imidazolium salts and podophyllotoxin-1,2,4-triazolium salts a1–a20 exhibited excellent cytotoxic activity. Among them, a6 was the most potent cytotoxic compound with IC50 values of 0.04–0.29 μM. Podophyllotoxin-1,2,3-triazole derivatives b1–b5 displayed medium cytotoxic activity, and podophyllotoxin-amine compounds c1–c3 has good cytotoxic activity with IC50 value of 0.04–0.58 μM. Furthermore, cell cycle and apoptosis experiments of compound a6 were carried out and the results exhibited that a6 could induce G2/M cell cycle arrest and apoptosis in HCT-116 cells.

Converting CO 2 into precious chemicals is considered to be a fundamental and effective tool for controlling the abundant CO 2 emitted. One of the most compelling methods for CO 2 conversion is the synthesis of cyclic carbonates by cycloaddition of CO 2 with epoxides. However, the development of materials with specific functionalities for CO 2 capture and conversion is still considered to be a significant challenge. Herein, a novel imidazolium salts and pyridine skeleton bifunctionalized hypercrosslinked polymers were prepared by FeCl 3 -catalyted Friedel-Crafts alkylation reaction. Various analytical techniques were used to investigate the properties of the catalysts. The bifunctionalized heterogeneous catalysts exhibited outstanding catalytic performances for CO 2 cycloaddition under mild conditions with an excellent yield of up to 99 %. Besides, the catalyst could bear various epoxides and no significant loss of activity after 6 cycles. The properties of metal-free, solvent-free, cocatalyst-free, easy-to-prepare, mild conditions, facility separation and recyclability make the bifunctionalized hypercrosslinked polymers useful for CO 2 cycloaddition. A novel imidazolium and pyridine bifunctionalized HCPs-NHC were prepared by Friedel-Crafts alkylation reaction, and the HCPs-NHC were considered as efficient catalyzes toward CO 2 conversion associated with the properties of metal-free, solvent-free, cocatalyst-free, easy preparation, inexpensive, mild conditions, recovery and recyclability. [Display omitted] • A novel imidazolium and pyridine skeleton bifunctionalized hypercrosslinked polymers was prepared by Friedel-Crafts reaction. • The catalysts exhibited outstanding catalytic performances for CO 2 cycloaddition under mild conditions with excellent yield. • The HCPs-NHC has the advantages of metal-free, solvent-free, cocatalyst-free, easy preparation, recovery and recyclability. • This work affords an approach for converting CO 2 into cyclic carbonates to help address the increasing greenhouse gases. [ABSTRACT FROM AUTHOR]

• 21-Imidazolium salt derivatives were prepared from 16-dehydropregnenolone acetate. • The key transformation was the rearrangement of 16,17-epoxides with HCl. • Binding affinity of synthesized compounds to CYP17A1 was evaluated. • Effects of the obtained compounds on various cancer cells were studied. • All imidazolium salts were active against the hormone-dependent line LNCaP. Nitrogen-containing steroids are known as prostate cancer therapeutics. In this work, a series of pregnane derivatives bearing an imidazolium moiety were synthesized using Δ16-20-ketones as starting material. An improved approach for the construction of the 20-keto-21-heterocycle-substituted fragment involved the rearrangement of 16,17-epoxides with HCl, followed by reaction of the formed α-chloroketone with 1-substituted imidazoles. Binding affinity analysis of the imidazolium steroids and their synthetic intermediates to human CYP17A1 showed only type I (substrate-like) interactions. The strongest affinity was observed for 16α,17α-epoxy-5α-pregnan-20-on-3β-ol (K d = 0.66 ± 0.05 µM). The steroid derivatives have been evaluated for antitumor activity against a range of prostate cancer cells as well as against various other solid tumor and hematologic cancer cell lines. All 21-imidazolium salts were active against the hormone-dependent prostate cancer line LNCaP. The most pronounced cytotoxicity in solid tumor and hematologic cancer cell lines was observed for intermediate product, 21-chloro-5α-pregn-16-en-20-on-3β-ol. Among the imidazolium salts, the derivatives with a single bond were more cytotoxic than their unsaturated congeners. [ABSTRACT FROM AUTHOR]

Imidazolium salts have always been well recognized as the precursors to ionic liquids. Various studies have been extended to their biological properties, in which many have discovered interesting results. In this study, a series of pyridine‐functionalized (benz)imidazolium salts were synthesized using the conventional synthetic method, and microwave irradiation. The products were tested biologically against a list of microorganisms via broth microdilution assay and cancer cell lines using a standard MTT assay. Lead compound 4 e exhibited great antimicrobial properties with lowest MIC value of 3.91 μg/mL against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus and Enterococcus faecalis. Remarkable anticancer properties of 3 f were shown with IC50 value as low as 0.71 μM against human colon cancer (HCT116). From our study, the MIC of 4 e and IC50 values of 3 f surpassed the potency of positive controls such as chloramphenicol (8.08–16.2 μg/mL) and cisplatin (10.78 μM) respectively. Additionally, the use of microwave irradiation has significantly reduced the reaction time from 5 days in a conventional setup, to a 3‐hour synthetic reaction in a microwave synthesizer. [ABSTRACT FROM AUTHOR]

Biofilm formation under cariogenic conditions contributes to dental caries development, in which Streptococcus mutans (S. mutans) is regarded as the major cariogenic bacteria. Here, we synthesized a series of imidazolium salts. Their properties of antimicrobial and anti-biofilm were investigated. The microdilution method crystal violet staining, and cell counting Kit-8 assay were used to screen imidazolium salts. Then, the bacterial composition in multi-species biofilm composed of S. mutans, Actinomyces naeslundii, and Streptococcus gordonii was quantified by quantitative PCR. The exopolysaccharide and morphology of the structure of multi-species biofilm were further observed by confocal laser scanning microscopy and scanning electron microscope, respectively. Imidazolium salts exhibited highly antimicrobial activity against oral pathogens, especially for S. mutans. Compounds with ortho-diisopropyl and para-methoxyl on N-moieties as well as bearing ancenaphthyl skeleton (C5) showed the lowest cytotoxicity and most efficient anti-biofilm activity. C5 inhibited approximately 50% of multi-species biofilm at 0.98 μg/mL. Notably, C5 resulted in 98.97% live S. mutans and 77.65% A. naeslundii decreased. Furthermore, the exopolysaccharide was reduced by 88%, along with a sparse and scattered microstructure. The imidazolium salts present low cytotoxicity and remarkable antimicrobial activity against S. mutans in multi-species biofilm, suggesting that they may have a great potential in anti-biofilm clinical applications. [ABSTRACT FROM AUTHOR]

Objective Biofilm formation under cariogenic conditions contributes to dental caries development, in which Streptococcus mutans (S. mutans) is regarded as the major cariogenic bacteria. Here, we synthesized a series of imidazolium salts. Their properties of antimicrobial and anti-biofilm were investigated.Methods The microdilution method crystal violet staining, and cell counting Kit-8 assay were used to screen imidazolium salts. Then, the bacterial composition in multi-species biofilm composed of S. mutans, Actinomyces naeslundii, and Streptococcus gordonii was quantified by quantitative PCR. The exopolysaccharide and morphology of the structure of multi-species biofilm were further observed by confocal laser scanning microscopy and scanning electron microscope, respectively.Results Imidazolium salts exhibited highly antimicrobial activity against oral pathogens, especially for S. mutans . Compounds with ortho-diisopropyl and para-methoxyl on N-moieties as well as bearing ancenaphthyl skeleton (C5) showed the lowest cytotoxicity and most efficient anti-biofilm activity. C5 inhibited approximately 50% of multi-species biofilm at 0.98 μg/mL. Notably, C5 resulted in 98.97% live S. mutans and 77.65% A. naeslundii decreased. Furthermore, the exopolysaccharide was reduced by 88%, along with a sparse and scattered microstructure.Conclusion The imidazolium salts present low cytotoxicity and remarkable antimicrobial activity against S. mutans in multi-species biofilm, suggesting that they may have a great potential in anti-biofilm clinical applications.

Low transition temperature mixtures (LTTMs) are a new generation of solvents that have found extensive application in organic synthesis. The interactions between the components often generate highly activated, catalytically active species, thus opening the possibility of using LTTMs as catalysts, rather than solvents. In this work, we introduce a nickel-based imidazolium LTTM, study its thermal behavior and explore its catalytic activity in the solvent-free allylation of heterocycles with allylic alcohols. This system is effective in this reaction, affording the corresponding products in excellent yield without the need for additional purifications, thus resulting in a very environmentally friendly protocol.

A series of cationic p-tert-butylcalix[4]arenes, with side-arms that are functionalized with imidazolium groups, have been synthesized in good yields. The parent tetrahydroxy para-t-butyl-calix[4]arene was dialkylated at the phenolic hydrogen atoms using α,ω-dibromo-alkanes to yield bis(mono-brominated) alkoxy-chains of variable length. The brominated side-arms in these compounds were then further alkylated with substituted imidazoles (N-methylimidazole, N-(2,4,6-trimethyl-phenyl)imidazole, or N-(2,6-di-isopropylphenyl)imidazole) to yield a series of dicationic calixarenes with two imidazolium groups tethered, via different numbers of methylene spacers (n = 2–4), to the calixarene moiety. Related tetracationic compounds, which contain four imidazolium units linked to the calix[4]arene backbone, were also prepared. In all of these compounds, the NMR data show that the calixarenes adopted a cone configuration. All molecules were characterized by NMR spectroscopy and by MS studies. Single crystal X-ray diffraction studies were attempted on many mono-crystals of these cations, but significant disorder problems, partly caused by occluded solvent in the lattice, and lack of crystallinity resulting from partial solvent loss, precluded the good resolution of most X-ray structures. Eventually, good structural data were obtained from an unusually disordered single crystal of 5a, (1,3)-Cone-5,11,17,23-tetra-t-butyl-25,27-di-hydroxy-26,28-di-[2-(N-2,6-diisopropylphenyl-imidazolium)ethoxy]calix[4]arene dibromide and its presumed structure was confirmed. The structure revealed the presence of H-bonded interactions and some evidence of π-stacking. Some of these imidazolium salts were reacted with nickelocene to form the nickel N-heterocyclic carbene (NHC) complexes 7a–7d. A bis-carbene nickel complex 8 was also isolated and its structure was established by single crystal X-ray diffraction studies. The structure was disordered and not of high quality, but the structural data corroborated the spectroscopic data.

Imidazolium salts (IMSs) are the subject of many studies showing their anticancer activities. In this research, a series of novel imidazolium salts substituted with lithocholic acid (LCA) and alkyl chains of various lengths (S1–S10) were evaluated against colon cancer cells. A significant reduction in the viability and metabolic activity was obtained in vitro for DLD-1 and HT-29 cell lines when treated with tested salts. The results showed that the activities of tested agents are directly related to the alkyl chain length, where S6–S8 compounds were the most cytotoxic against the DLD-1 line and S4–S10 against HT-29. The research performed on the xenograft model of mice demonstrated a lower tendency of tumor growth in the group receiving compound S6, compared with the group receiving 5-fluorouracil (5-FU). Obtained results indicate the activity of S6 in the induction of apoptosis and necrosis in induced colorectal cancer. LCA-based imidazolium salts may be candidates for chemotherapeutic agents against colorectal cancer. [ABSTRACT FROM AUTHOR]

Keywords: acetylenic iminium salts; imidazolium salts; nitrones; thermal rearrangement; [3+2] cycloaddition; 4-isoxazolines EN acetylenic iminium salts imidazolium salts nitrones thermal rearrangement [3+2] cycloaddition 4-isoxazolines 505 515 11 07/18/22 20220701 NES 220701 1 Introduction 2,3-Dihydroisoxazoles (4-isoxazolines) are partially unsaturated five-membered O,N-heterocycles, which are known for a wide range of transformations, of which their tendency toward an array of thermal rearrangements is both synthetically useful and mechanistically remarkable. 3 Conclusions Propyniminium salts with an internal or terminal CC triple bond were identified as excellent dipolarophiles for [3+2] cycloaddition reaction with two acyclic nitrone dipoles. While reaction rates of the nitrone-alkyne cycloaddition depend on various factors, it is well known that electron-withdrawing substituents at the C C triple bond can lead to a considerable rate acceleration. [Extracted from the article]

The mitigation of environmental impacts caused by greenhouse gas emissions has become increasingly urgent, and the use of CO 2 as a primary carbon source is an alternative in chemical transformations, including the synthesis of organic carbonates, formic acid, or methanol. This work aims to synthesize ionic liquids from the imidazolium cation family to be used in the cycloaddition of CO 2 with ILs anchored in SiO 2 -clay heterostructure, MCM-41 and KIT-6 mesoporous materials, as well as the hydrogenation of CO 2 with ILs added to ruthenium complexes, i.e., two catalytic systems. The most satisfactory result for CO 2 cycloaddition (TON PC = 226) was obtained using the IL (MeO) 3 Sipmim.Cl anchored in SiO 2 -clay heterostructure (0.16 mol%) as the catalyst and ZnBr 2 (0.04 mol%) as the co-catalyst. The hydrogenation was conducted with the IL (edaO) 3 Sipmim.Cl and the ruthenium complex Ru-PNN were not successful, but with co-catalyst PEHA, formic acid/formamide was produced (TON Form = 552). The unique catalytic system that showed activity for forming methanol was the commercial Ru-MACHO, Ru-C 29 H 30 ClNOP 2 , (TON MeOH = 3.3). These results highlight the potential of ruthenium-based complexes and supported ionic liquids as active systems in CO 2 conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • In this study, preparation and structural definition of silver(I)-NHC complexes were accomplished. A single-crystal of 3 h shows that coordination geometry is a slightly distorted linear coordination geometry around the silver(I) center. • Density functional theory (DFT) optimization revealed its geometry, while time-dependent DFT (TD-DFT) calculations shed light on its optical properties • Furthermore the newly synthesized ligands and silver(I) complexes were evaluated for their in vitro anticancer activity against three human cancer cell lines.Most of the newly synthesized silver(I) complexes exhibited better activity than the ligands. Due to the success of Ag-NHCs in biological applications, interest in the synthesis and applications of such compounds is increasing rapidly. Therefore, in this study, preparation and structural definition of silver(I)–NHC complexes were accomplished. These complexes were synthesized by combining a metal source, Ag 2 O, with imidazolium salts in dichloromethane. A comprehensive characterization process was carried out for both the ligands and their resulting complexes. This involved utilizing various analytical techniques, such as elemental analysis, LC-MS, FTIR and NMR spectroscopy. Further, structure of the 3 h complex was determined by X-ray crystallography. A single-crystal of 3 h shows that coordination geometry is a slightly distorted linear coordination geometry around the silver(I) center. Furthermore, our combined experimental and theoretical approach provided insights into the crystal structure, coordination geometry, and intermolecular interactions stabilizing the complex's lattice. Density functional theory (DFT) optimization revealed its geometry, while time-dependent DFT (TD-DFT) calculations shed light on its optical properties. Furthemore the newly synthesized ligands and silver(I) complexes were evaluated for their in vitro anticancer activity against three human cancer cell lines including hepatocellular carcinoma (HePG2), lung adenocarcinoma (A549) and breast adenocarcinoma (MCF7). Most of the newly synthesized silver(I) complexes exhibited better activity than the ligands, and the results have been compared with Cisplatin as a reference drug. [ABSTRACT FROM AUTHOR]

Chlorella sorokiniana is a microalgae with high amounts of carotenoids, but the extraction methods need to be improved. This work hypothesized that the combination of ionic liquids (ILs) and ultrasound would provide a fast and efficient process for carotenoid extraction, allowing for the reuse of ILs in several extractive cycles. This study aimed to develop an improved ILs/ultrasound-based method for extracting carotenoids from C. sorokiniana. The potential reuse of ILs in five consecutive extraction cycles and the recovery of carotenoids was also examined. Moreover, the antioxidant activity of the carotenoid extracts and their effects on metabolic cell viability and cell death were investigated using HT22 neuronal cells. Initial tests with four ILs and acetone as a control were carried out in an ultrasonic probe. The ILs (1-butyl-3-methylimidazolium chloride [BMIM][Cl]; 1-hexyl-3-methylimidazolium chloride [HMIM][Cl]) were selected for the 25−1 fractional experimental design. The maximized parameters obtained in the experimental design were the following: IL ([HMIM][Cl]), a 1:10 solid-liquid ratio, a 1:4 IL-cosolvent ratio, and two repetitions of extraction with 7.5 min (with an extraction yield of 1.29 mg·g‐1 of dry matter). A total of 11 carotenoids were separated, and nine were identified, the major ones being lutein and β-carotene. [HMIM][Cl] recyclability using resin Amberlite XAD-7HP was efficient for at least five cycles. On average, 91 % of the IL was recovered, and the pigment yield increased by 40 %. The antioxidant activities of the extracts obtained using [HMIM][Cl] and acetone were 1.65 μmol and 2.32 μmol of α-tocopherol, respectively. Both extracts (≤ 4.0 μg·mL‐1) exhibited no significant toxicity to HT22 cells. The proposed method is an innovative and improved approach for carotenoid extraction from C. sorokiniana due to its short extraction times and high process yield. [HMIM][Cl] demonstrated stability in reuse cycles and proved to have the potential for obtaining carotenoids from C. sorokiniana. [Display omitted] • Ionic liquid and ultrasound were efficient in extracting carotenoids from microalgae. • The maximized process was 15 min, yielding 1.29 mg of carotenoids·g−1. • [HMIM][Cl] may be reused in at least five cycles, increasing extraction efficiency. • The antioxidant activity of carotenoids obtained by IL was 1.65 μmol of α-tocopherol. • The carotenoid extract obtained by [HMIM][Cl] was safe in HT22 cells at 4.0 μg·mL−1. [ABSTRACT FROM AUTHOR]

Starting with fluorinated benzylamines, a series of 2-unsubstituted imidazole N-oxides was prepared and subsequently deoxygenated in order to prepare the corresponding imidazoles. The latter were treated with benzyl halides yielding imidazolium salts, which are considered fluorinated analogues of naturally occurring imidazolium alkaloids known as lepidilines A and C. A second series of oxa-lepidiline analogues was obtained by O-benzylation of the initially synthetized imidazole N-oxides. Both series of imidazolium salts were tested as anticancer and antiviral agents. The obtained results demonstrated that the introduction of a fluorine atom, fluoroalkyl or fluoroalkoxy substituents (F, CF3 or OCF3) amplifies cytotoxic properties, whereas the cytotoxicity of some fluorinated lepidilines is promising in the context of drug discovery. All studied compounds revealed a lack of antiviral activity against the investigated viruses in the nontoxic concentrations. [ABSTRACT FROM AUTHOR]

The synthesis of five selenium complexes bearing imidazole-based N-heterocyclic carbene ligands (Se-NHC) are reported. The adducts were characterized by elemental and spectroscopic analysis (FTIR, 1H and 13C NMR). Single-crystal XRD confirmed the structures of two Se-NHC adducts, VIII and XI. Zone of inhibition (ZOI) values of Se-NHC complexes were evaluated towards two bacterial (Bacillus thuringiensis and Escherichia coli) and one fungal strain (Candida albicans). The most active tested compound was XI with inhibition value of 24.1 ± 0.1 mm against E. coli, and it showed higher activity than Tetracycline (reference drug). Similarly, XI exhibited good inhibition potential against C. albicans (26.5 ± 0.2 mm). The hemolytic assay demonstrated that the tested compounds (VIII-XII) are non-toxic to healthy human blood; however, thrombolysis indicated that VIII-XII could be used as potential thrombolytic agents. It is concluded that Se-NHC carbene adducts having more aromatic rings at terminal nitrogens of imidazole are more effective than other tested compounds. Se-NHC compounds have more efficacy against bacterial strains than fungal strain. [ABSTRACT FROM AUTHOR]

Synthetically relevant 2-unsubstituted imidazole N-oxides were obtained by using the ball-milling mechanochemical method. The presented approach extended the scope of the known method and enabled the preparation of hitherto little known N(1)-aryl-substituted derivatives, which are of interest as starting materials for the synthesis of more complex imidazole-based organic materials, generally in good to excellent yields. In addition, selected one-pot mechanochemical transformations including N- and O-alkylations as well as sulfur transfer reactions based on either (3+2)-cycloaddition reaction with 2,2,4,4-tetramethylcyclobutane-1,3-dithione or sulfurization of the transient imidazol-2-ylidenes, generated from corresponding imidazolium salts, were studied. The reported results can be considered as a continuation of long-term studies focused on the synthesis and applications of 2-unsubstituted imidazole N-oxides. [ABSTRACT FROM AUTHOR]

Due to the increase in life expectancy worldwide, age-related disorders such as neurodegenerative diseases (NDs) have become more prevalent. Conventional treatments comprise drugs that only attenuate some of the symptoms, but fail to arrest or delay neuronal proteotoxicity that characterizes these diseases. Due to their diverse biological activities, imidazole rings are intensively explored as powerful scaffolds for the development of new bioactive molecules. By using C. elegans, our work aims to explore novel biological roles for these compounds. To this end, we have tested the in vivo anti-proteotoxic effects of imidazolium salts. Since NDs have been largely linked to impaired antioxidant defense mechanisms, we focused on 1-Mesityl-3-(3-sulfonatopropyl) imidazolium (MSI), one of the imidazolium salts that we identified as capable of improving iron-induced oxidative stress resistance in wild-type animals. By combining mutant and gene expression analysis we have determined that this protective effect depends on the activation of the Heat Shock Transcription Factor (HSF-1), whereas it is independent of other canonical cytoprotective molecules such as abnormal Dauer Formation-16 (DAF-16/FOXO) and Skinhead-1 (SKN-1/Nrf2). To delve deeper into the biological roles of MSI, we analyzed the impact of this compound on previously established C. elegans models of protein aggregation. We found that MSI ameliorates β-amyloid-induced paralysis in worms expressing the pathological protein involved in Alzheimer's Disease. Moreover, this compound also delays age-related locomotion decline in other proteotoxic C. elegans models, suggesting a broad protective effect. Taken together, our results point to MSI as a promising anti-proteotoxic compound and provide proof of concept of the potential of imidazole derivatives in the development of novel therapies to retard age-related proteotoxic diseases. [ABSTRACT FROM AUTHOR]

We show that 1‐(2‐hydroxyethyl)‐1H‐imidazol‐3‐ium and 1‐(2‐hydroxyethyl)‐3‐methyl‐1H‐imidazol‐3‐ium salts, as well as the salts of their nitrite esters, that include oxidizing anions (so‐called explosphores) such as nitrate, picrate and perchlorate„ are endowed with high enthalpies of decomposition, high decomposition temperatures, and high densities. This combined with detonation velocities and pressures calculated using Explo5, indicates that especially the perchlorate salts have potential as energetic materials. All the studied salts are easily preparable in up to gram scale through two or three synthetic steps from simple imidazole. Many of these salts are ionic liquids, which may render them useful as energetic plasticizers or gel filled materials. [ABSTRACT FROM AUTHOR]

Due to the increase in life expectancy worldwide, age-related disorders such as neurodegenerative diseases (NDs) have become more prevalent. Conventional treatments comprise drugs that only attenuate some of the symptoms, but fail to arrest or delay neuronal proteotoxicity that characterizes these diseases. Due to their diverse biological activities, imidazole rings are intensively explored as powerful scaffolds for the development of new bioactive molecules. By using C. elegans, our work aims to explore novel biological roles for these compounds. To this end, we have tested the in vivo anti-proteotoxic effects of imidazolium salts. Since NDs have been largely linked to impaired antioxidant defense mechanisms, we focused on 1-Mesityl-3-(3-sulfonatopropyl) imidazolium (MSI), one of the imidazolium salts that we identified as capable of improving iron-induced oxidative stress resistance in wild-type animals. By combining mutant and gene expression analysis we have determined that this protective effect depends on the activation of the Heat Shock Transcription Factor (HSF-1), whereas it is independent of other canonical cytoprotective molecules such as abnormal Dauer Formation-16 (DAF-16/FOXO) and Skinhead-1 (SKN-1/Nrf2). To delve deeper into the biological roles of MSI, we analyzed the impact of this compound on previously established C. elegans models of protein aggregation. We found that MSI ameliorates β-amyloid-induced paralysis in worms expressing the pathological protein involved in Alzheimer’s Disease. Moreover, this compound also delays age-related locomotion decline in other proteotoxic C. elegans models, suggesting a broad protective effect. Taken together, our results point to MSI as a promising anti-proteotoxic compound and provide proof of concept of the potential of imidazole derivatives in the development of novel therapies to retard age-related proteotoxic diseases.

Novel salts based on 1,3‐dibutyl‐4‐(2‐hydroxyphenyl)‐1H‐imidazolium bromide or iodide have been developed as bifunctional organocatalysts for the cycloaddition reaction of epoxides and isocyanates to form 3,4‐ and 3,5‐disubstituted oxazolidin‐2‐ones. The molecular structure of these compounds was determined spectroscopically and confirmed by X‐ray diffraction analysis. Imidazolium compounds were screened as catalysts to produce a range of oxazolidinones. The influence of the substituents on the aromatic ring and the counterion of the catalysts on the catalytic activity have been studied, showing that 1,3‐dibutyl‐4‐(5‐fluro‐2‐hydroxyphenyl)‐1H‐imidazolium iodide (4 d) was the most active catalyst for this process in the absence of a cocatalyst. [ABSTRACT FROM AUTHOR]

Imidazolium salts have ubiquitous applications in energy research, catalysis, materials and medicinal sciences. Here, we report a new strategy for the synthesis of diverse heteroatom‐functionalized imidazolium and imidazolinium salts from easily available 1,4‐diaza‐1,3‐butadienes in one step. The strategy relies on a discovered family of unprecedented nucleophilic addition/cyclization reactions with trialkyl orthoformates and heteroatomic nucleophiles. To probe general areas of application, synthesized N‐heterocyclic carbene (NHC) precursors were feasible for direct metallation to give functionalized M/carbene complexes (M=Pd, Ni, Cu, Ag, Au), which were isolated in individual form. The utility of the chloromethyl function for the postmodification of the synthesized salts and Pd/carbene complexes was demonstrated. The obtained complexes and imidazolium salts demonstrated good activities in Pd‐ or Ni‐catalyzed model cross‐coupling and C−H activation reactions. [ABSTRACT FROM AUTHOR]

We report the use of imidazolium based tunable aryl alkyl ionic liquids (TAAILs) as solvents in the Mizoroki–Heck reaction. Different commercially available palladium sources, inorganic bases, TAAILs and reaction conditions were tested for the synthesis of trans‐stilbene using bromobenzene and styrene. A variety of different stilbene derivatives were synthesized with exclusive formation of the (E)‐isomers and isolated yields up to 97 %. We were able to optimize the reaction conditions using only 0.25 mol% of Pd(OAc)2 as the catalyst and a reaction time of 4 hours. No additional ligands or additives are used in the reaction. The catalytic system using TAAILs achieved higher yields than commercially available imidazolium and phosphonium ionic liquids, demonstrating the potential of tailored ionic liquids as a reaction medium for the Mizoroki–Heck reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient catalytic system for ethanol homologation to biofuel. • Suitable transformation of wine waste bio-ethanol to second generation biofuel. • Boosting the Guerbet reaction: a tandem homogeneous catalytic solution. The catalytic activity of anionic ruthenium complexes toward the transformation of bio-ethanol to 1-butanol and higher alcohols is found to be dependent on the imidazolium counterion. After the identification of a parallel reaction involving the catalyst in hydrogen evolution, conversion and selectivity are impressively boosted by the addition of p-benzoquinones as co-catalysts. The catalytic system avoids the side reaction and led to highly competitive conversions up to 88% (0.2 % mol ruthenium catalyst loading, 1.5 % mol benzoquinone loading). Butanol and higher alcohols are produced in yields up to 85% (overall selectivity 97%) as a mixture of valuable alcohols for advanced biofuel and lubricants applications. The catalytic system can be recycled and the reaction shows comparable efficiency on a real matrix (alcohol from wine production chain wastes) even in the presence of significant amounts of water, thus closing a hypothetic economic circle. A reaction mechanism is proposed for the most promising ruthenium complex working in cooperation with the most efficient co-catalyst: p-benzoquinone. [ABSTRACT FROM AUTHOR]

Reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) with phthalimide, quinazolinedione, thiophenole and 4-pyridinethiole led to the formation of the hydrogen-bonded salts, imidazolium phthalimide (2), imidazolium quinazolinedione (3), imidazolium thiophenolate (4) and imidazolium 4-pyridinethiolate (5), respectively, in good yield. In crystals of 2, the anion is linked to the imidazolium cation by a C–H···O hydrogen bond, while in 3 and 5 C–H···N hydrogen bonds are observed. In 4, the imidazolium ion is linked to the anion by C–H···S hydrogen bonds. In compounds 2, 3 and 5, the interionic hydrogen bonds are close to linearity, while the interionic hydrogen bond angle in 4 is 148.5(9)°. [ABSTRACT FROM AUTHOR]

New bifunctional amphiphilic oxyethylimidazolium derivatives of calix[4]arene with terminal alkynyl or azide fragments in the polar moiety of the molecule were synthesized. The aggregation characteristics (critical aggregation concentrations, size, and zeta potential) of the synthesized macrocyclic azides, alkynes, and their mixtures were studied. Polymeric particles were obtained under the azide/alkyne cycloaddition conditions. Covalent cross-linking of the aggregate core was proved by IR spectroscopy. The size, molecular weight, and morphology of the polymerized particles were determined. The catalytic properties of the in situ formed Pd(OAc)2 complex with the prepared polymerized particles were studied in the model Suzuki cross-coupling reaction in an aqueous medium. [ABSTRACT FROM AUTHOR]

Abstract A convenient, large-scale, and cost-efficient synthesis of 4,5-diarylsubstituted N,N-diarylimidazolium salts is described. A variety of 1,3,4,5-tetraaryl imidazolium salts with increasing electron donation and steric bulk of the N-aryl groups was synthesized in good yields. In the key step, readily available N,N′-diarylthioureas and benzoin/anisoin are coupled to give imidazole-2-thiones, followed by imidazolium salt formation by oxidative desulfurization. In this way, N,N-diarylimidazolium salts with 2-methoxy, 2-methyl, and 2-isopropyl substituents could be obtained; the synthesis of their 2-tert-butyl, 2,6-dimethyl, and 2,6-diisopropyl analogues failed.

The synthesis and spectroscopic and structural characterisation of new 3,5-dibromophenyl-functionalised imidazolium salts and their corresponding [Au(NHC)2]+ complexes is reported. X-ray diffraction studies revealed intra- and intermolecular interactions involving the 3,5-dibromophenyl group, including Br...π interactions with imidazolyl and C6 arene rings. Au-NHC complexes functionalised with 3,5-dibromophenyl substituents showed potent activity against OVCAR-8 (ovarian cancer) cells at low micromolar concentrations. [ABSTRACT FROM AUTHOR]

Solid state organic electrolytes offer the advantages of low flammability, superior thermal stability and straightforward production with the ability to form a stable solid-electrolytes interface layer. The ease of synthesis of these zwitterions and their high thermal stability made them desirable materials for their potential lithium ion battery applications. Here in, series of imidazolium and benzimidazolium salts with high thermal stability and simple synthetic approach were prepared. Sulfonate functionalized zwitterions with varying alkyl groups including n-butyl, sec-butyl and 2-ethylhexyl were synthesized based on benzimidazole and imidazole moieties and characterized. The six zwitterions synthesized exhibited high thermal stability (317-341 °C).

We synthesized new imidazolium‐based tunable aryl alkyl ionic liquids (TAAILs) with the weakly coordinating tetrakis(pentafluoroethyl)gallate anion, [Ga(C2F5)4]−. Phenyl and phenyl derivatives (2‐Me, 4‐OMe, 2,4‐F) were combined with varying alkyl chain lengths at the imidazolium core leading to TAAILs, which were investigated with regard to their viscosity, conductivity, and electrochemical window and compared to EMIM and BMIM standard cations. Remarkable low viscosities of 29 cP at 25 °C for [BMIM][Ga(C2F5)4] were achieved. However, the EMIM and BMIM gallates show electrochemical instability, releasing pentafluoroethane at a voltage of 1.5 V. The 2‐Me‐substituted gallate‐TAAILs slowly decompose over several weeks, whereas all other gallate‐TAAILs showed no decomposition at all. With electrochemical windows of up to 5.15 V and low viscosities in a range of 66–162 cP, the gallate‐TAAILs are promising candidates as electrolytes in electrochemical applications. [ABSTRACT FROM AUTHOR]

• Thirteen new imidazolium salts and their corresponding Ag(I)-NHC complexes were successfully synthesised and characterised. • Compounds with bisimidazolium structures and long aliphatic alkyl N-1/N-3 side chains possess better antimicrobial potency with minimum inhibitory concentration (MIC) ranging from 0.12 to 7.81 µg/mL against selected six Gram-positive bacterial strains (Staphylococcus aureus and Enterococcus faecalis), two Gram-negative bacteria (Escherichia coli and Shigella flexneri) and two fungal strains (Candida albicans). • The MIC values of a lead compound Ag-4d were in the order of 0.24–0.98 µg/mL, surpassing the potencies of positive controls such as AgNO 3 (7.81–15.63 µg/mL) and chloramphenicol (1.95–31.25 µg/mL). Current drug research has been focusing on silver N -heterocyclic carbene (NHC) complex. Its metal-ligand bonds are stabilised by the strong-electron donor nature of NHC, ultimately increasing its antimicrobial properties. A series of imidazolium salts and their corresponding Ag(I)-NHC complexes with different NHC side chains in terms of alkyl chain length and mono/biscarbene functionalities have been successfully synthesised, characterised, and evaluated for their potential antimicrobial activities. It was shown that the imidazolium salts and Ag(I)-NHC complexes with long aliphatic alkyl N -1/ N -3 side chains and bisimidazolium ligands possess promising bioactivities in general, with minimum inhibitory concentration (MIC) against microbes ranging from 0.12 to 7.81 µg/mL against selected six Gram-positive bacterial strains (Staphylococcus aureus and Enterococcus faecalis), two Gram-negative bacteria (Escherichia coli and Shigella flexneri) and two fungal strains (Candida albicans) for 2–7d & Ag-2–7d. It was found that the compounds with biscarbene structures (6d & Ag-6d) possess less toxic effects against immortalised human keratinocyte (HaCaT) cells. However, it must be noted that the toxic effect against HaCaT is higher among Ag(I)-NHC complexes (Ag-4d & Ag-6d) than their corresponding imidazolium salts (4d & 6d) in general. Hence, the variation of side chains, number of imidazolium centres and their respective cytotoxic effect provide insights into the future drug modification towards enhanced antimicrobial activities with minimal side effects. [Display omitted] [ABSTRACT FROM AUTHOR]

Adamantyloxyamine reacts with formaldehyde to give N-(adamantyloxy)formaldimine as a room-temperature-stable compound that exists in solution in monomeric form. This product was used for reactions with α-hydroxyiminoketones leading to a new class of 2-unsubstituted imidazole 3-oxides bearing the adamantyloxy substituent at N(1). Their reactions with 2,2,4,4-tetramethylcyclobutane-1,3-dithione or with acetic acid anhydride occurred analogously to those of 1-alkylimidazole 3-oxides to give imidazol-2-thiones and imidazol-2-ones, respectively. Treatment of 1-(adamantyloxy)imidazole 3-oxides with Raney-Ni afforded the corresponding imidazole derivatives without cleavage of the N(1)–O bond. Finally, the O-alkylation reactions of the new imidazole N-oxides with 1-bromopentane or 1-bromododecane open access to diversely substituted, non-symmetric 1,3-dialkoxyimidazolium salts. Adamantyloxyamine reacts with glyoxal and formaldehyde in the presence of hydrobromic acid yielding symmetric 1,3-di(adamantyloxy)-1H-imidazolium bromide in good yield. Deprotonation of the latter with triethylamine in the presence of elemental sulfur allows the in situ generation of the corresponding imidazol-2-ylidene, which traps elemental sulfur yielding a 1,3-dihydro-2H-imidazole-2-thione as the final product.

Four new series of ionic liquid crystals derived from imidazole bromonium and benzimidazole bromonium salts with spacer alkyl chain (Cn, n = 2, 4) were synthesised and characterised. The following tests and measurements have been performed: the FT-IR, 1H-NMR and 13C-NMR spectroscopy in addition to a CHN elemental analysis techniques. Both the differential scanning calorimetry and the polarising optical microscopy measurements are applied for the evaluation of liquid crystals properties. The outcome confirms the existence of a smectic A liquid crystalline phase. A Density Functional Theory computations were performed to obtain the shape of the molecular structure that corresponds to the ground-state energy. [ABSTRACT FROM AUTHOR]

Starting with fluorinated benzylamines, a series of 2-unsubstituted imidazole N-oxides was prepared and subsequently deoxygenated in order to prepare the corresponding imidazoles. The latter were treated with benzyl halides yielding imidazolium salts, which are considered fluorinated analogues of naturally occurring imidazolium alkaloids known as lepidilines A and C. A second series of oxa-lepidiline analogues was obtained by O-benzylation of the initially synthetized imidazole N-oxides. Both series of imidazolium salts were tested as anticancer and antiviral agents. The obtained results demonstrated that the introduction of a fluorine atom, fluoroalkyl or fluoroalkoxy substituents (F, CF3 or OCF3) amplifies cytotoxic properties, whereas the cytotoxicity of some fluorinated lepidilines is promising in the context of drug discovery. All studied compounds revealed a lack of antiviral activity against the investigated viruses in the nontoxic concentrations.

In the present work, a series of twenty seven new 4-Nitroimidazolium based protic molten salts and /or ionic liquids with organic anions namely N1-Alkyl-2-methyl-4-nitro-3-imidazolium-3′,5′-diaminobenzoates, N1-Alkyl-2-methyl-4-nitro-3-imidazolium-3′,5′-dinitrobenzoates, N1-Alkyl-2-methyl-4-nitro-3-imidazolium-ferulate and N1-Alkyl-2-methyl-4-nitro-3-imidazolium-5′-nitromonophthalates have been synthesized by the simple protonation of N1-Alkyl-2-methyl-4-nitro-1H-imidazoles with 3,5-Diaminobenzoic acid, 3,5-Dinitrobenzoic acid, (E)-3-(4-Hydroxy-3-methoxyphenyl) acrylic acid and 5-Nitrophthalic acid respectively. All the synthesized imidazolium based molten salts and/or ionic liquids were obtained with excellent yields (95–99%) and characterized by elemental analysis, 1H NMR and 13C NMR spectral studies. The conductivity data and pKa values were measured in 1:1 DMSO and H2O at room temperature.

Two imidazolium hypodiphosphates, (C3H5N2)(H3P2O6) (I) and (C3H5N2)2(H2P2O6) (II), have been synthesized and structurally characterized. In both metal‐free organic–inorganic hybrids (I) and (II), the hypodiphosphate mono‐ and dianions, (H3P2O6)− and (H2P2O6)2−, form hydrogen‐bonded frameworks of different types, to which the organic cations are linked via N—H...O and C—H...O hydrogen bonds. The purity of the compounds was confirmed by powder X‐ray diffraction. Differential scanning calorimetry of compound (I) revealed two structural phase transitions: continuous at 311.8 K [cooling/heating; from high‐temperature phase (HTP) to room‐temperature phase (RTP)] and a discontinuous one at 287.9/289.2 K [RTP → low‐temperature phase (LTP)]. Compound (I) is characterized in a wide temperature range by single‐crystal and powder X‐ray diffraction methods. Crystal structures of high‐ and low‐temperature phases are determined, which show orthorhombic (HTP, Pnna, No. 52) → monoclinic (LTP, P21/n11, No. 14, a‐axis doubled) structural change on cooling with an intermediate incommensurately modulated phase (RTP). Dynamic properties of polycrystalline (I) were studied by means of dielectric spectroscopy. The dielectric behaviour is explained by the motion of imidazolium cations. [ABSTRACT FROM AUTHOR]

The electrochemical behavior of 1-ferrocenylmethyl-3-(methyl)-imidazolium iodide (or mesityl) imidazolium was studied by cyclic voltammetry at glassy carbon electrode in midiums organic to determine the influences of electronic imidazolium group on the ferrocene. The experimental results indicated that the redox reaction was reversible. Mass transport towards the electrode is a simple diffusion process and the diffusion coefficient (D) for redox couple has been also calculated and we have evaluated the heterogeneous charge transfer rate constant (K0). [ABSTRACT FROM AUTHOR]