- On the effects of head-group volume on the adsorption and aggregation of 1-(n-hexadecyl)-3-Cm-imidazolium bromide and chloride surfactants in aqueous solutions
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The effects of the length of alkyl side chain (Cm) of ionic liquid-based surfactants (ILBSs) on their adsorption at the water/air interface, and aggregation in aqueous solutions were investigated for the series 1-(n-hexadecyl)-3-Cm-imidazolium bromides and chlorides, where Cm = C1-C4 for the bromides, and C1-C5 for the chlorides. These physicochemical properties were calculated from surface tension, conductivity, and fluorescence data. It was found that increasing the length of Cm (i.e., volume of the head group) leads to enhancement of surface activity, increase in the area per surfactant molecule at the water/air interface (Amin) and the degree of counter-ion dissociation (αmic). Our data also indicated that increasing the volume of the head group results in a decrease of the critical micelle concentration (cmc), Gibb's free energy of adsorption and micellization, and microscopic polarity of interfacial water. In order to delineate the effects of the presence of unsaturation in the HG, we included members that carry Cm = vinyl and allyl in the bromide series. The effect of these groups was found to be similar to removing a methylene group from Cm. The dependence of the solubilization of a lipophilic dye (Sudan IV) and a drug (nitrendipine) on the length of Cm was also studied.
- Keppeler, Nicolas,Galgano, Paula D.,da Silva Santos, Soraya,Malek, Naved I.,El Seoud, Omar A.
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- New eco-friendly 1-alkyl-3-(4-phenoxybutyl) imidazolium-based ionic liquids derivatives: A green ultrasound-assisted synthesis, characterization, antibacterial activity and POM analyses
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In view of the emerging importance of the ILs as "green" materials with wide applications and our general interests in green processes, a series of a twenty five new 1-alkyl-3-(4-phenoxybutyl) imidazolium-based ionic liquids (ILs) derivatives is synthesized using a facile and green ultrasound-assisted procedure. Their structures were characterized by FT-IR, 1H-NMR, 13C-NMR, 11B, 19F, 31P, and mass spectrometry. Antimicrobial screens of some selected ILs were conducted against a panel of Gram-positive and Gram-negative bacteria. The antimicrobial activity of each compound was measured by determination of the minimal inhibitory concentration (MIC) yielding very interesting and promising results. Their antibacterial activities are reported, and, on the basis of the experimental and virtual POM screening data available, attempt is also made to elucidate the structure activity relationship.
- Messali, Mouslim,Aouad, Mohamed R.,El-Sayed, Wael S.,Ali, Adeeb Al-Sheikh,Hadda, Taibi Ben,Hammouti, Belkheir
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- Synthese et proprietes antibacteriennes et antifongiques d'une serie de 1-alkylimidazoles
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A homologous series of 1-alkylimidazoles (pentyl to octadecyl) has been obtained with a good yield (75-95percent) by the phase transfer catalyzed reaction of imidazole with the appropriate alkyl halides.The antifungal and antibacterial activities of these compounds were tested.A poor activity was observed towards the Gram-negative (Gram-) microorganisms, whereas the aerobic and anaerobic Gram-positive (Gram+) microorganisms and some yeasts (Pityrosporum ovale) were inhibited.We found that the inhibitory potency of such compounds increased with increasing chain length,passing through a maximum with chain length C10-C13 and decreased for the higher homologs.An explanation is suggested in relation to the ability of these compounds to bind with the active sites of the microorganisms and to adopt a conformation able to promote the migration through the biological membranes.
- Savignac, A. de,Roques, C.,Hinedi, M.,Michel, G.,Lattes, A.
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- Liquid Nickel Salts: Synthesis, Crystal Structure Determination, and Electrochemical Synthesis of Nickel Nanoparticles
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New nickel-containing ionic liquids were synthesized, characterized and their electrochemistry was investigated. In addition, a mechanism for the electrochemical synthesis of nanoparticles from these compounds is proposed. In these so-called liquid metal salts, the nickel(II) cation is octahedrally coordinated by six N-alkylimidazole ligands. The different counter anions that were used are bis(trifluoromethanesulfonyl)imide (Tf2N-), trifluoromethanesulfonate (OTf-) and methanesulfonate (OMs-). Several different N-alkylimidazoles were considered, with the alkyl sidechain ranging in length from methyl to dodecyl. The newly synthesized liquid metal salts were characterized by CHN analysis, FTIR, DSC, TGA and viscosity measurements. An odd-even effect was observed for the melting temperatures and viscosities of the ionic liquids, with the complexes with an even number of carbon atoms in the alkyl chain of the imidazole having a higher melting temperature and a lower viscosity than the complexes with an odd number of carbons. The crystal structures of several of the nickel(II) complexes that are not liquid at room temperature were determined. The electrochemistry of the compounds with the lowest viscosities was investigated. The nickel(II) cation could be reduced but surprisingly no nickel deposits were obtained on the electrode. Instead, nickel nanoparticles were formed at 100 % selectivity, as confirmed by TEM. The magnetic properties of these nanoparticles were investigated by SQUID measurements.
- Sniekers, Jeroen,Verguts, Ken,Brooks, Neil R.,Schaltin, Stijn,Phan, Thanh Hai,Trung Huynh, Thi Mien,Van Meervelt, Luc,Defeyter, Steven,Seo, Jin Won,Fransaer, Jan,Binnemans, Koen
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- Iron(II) spin-crossover complexes with Schiff base like ligands and N-alkylimidazoles
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Three new iron(II) spin-crossover complexes with N2O2-coordinating Schiff base like equatorial ligands and alkylimidazole ligands in the axial positions were synthesised. The chain length of the alkylimidazole was varied from the previously published 1 to 5, 7 and 10 carbon atoms to investigate the influence of the alkyl chain length on the spin-transition behaviour in solution and in the solid state. The crystal structures of [1(HeptIm)2] and [1(DecIm)2] (1 = Fe complex with equatorial Schiff base like ligand; HeptIm = N-heptylimidazole, DecIm = N-decylimidazole) and the packing of the molecules in the crystals are discussed.
- Schlamp, Stephan,Lochenie, Charles,Bauer, Tobias,Kempe, Rhett,Weber, Birgit
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- Chemo-immunotherapeutic antimalarials targeting isoprenoid biosynthesis
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We synthesized 30 lipophilic bisphosphonates and tested them in malaria parasite killing (targeting parasite geranylgeranyl diphosphate synthase, GGPPS) and human γδ T cell activation (targeting human farnesyl diphosphate synthase, FPPS). Similar patterns of activity were seen in inhibiting human FPPS and Plasmodium GGPPS, with short to medium chain-length species having most activity. In cells, shorter chain-length species had low activity, due to poor membrane permeability, and longer chain length species were poor enzyme inhibitors. Optimal activity was thus seen with ~C 10 side-chains, which have the best combination of enzyme inhibition and cell penetration. We also solved the crystal structure of one potent inhibitor, bound to FPPS. The results are of interest since they suggest the possibility of a combined chemo/immuno-therapeutic approach to antimalarial development in which both direct parasite killing and γδ T cell activation can be achieved with a single compound.
- Zhang, Yonghui,Zhu, Wei,Liu, Yi-Liang,Wang, Hong,Wang, Ke,Li, Kai,No, Joo Hwan,Ayong, Lawrence,Gulati, Anmol,Pang, Ran,Freitas-Junior, Lucio,Morita, Craig T.,Oldfield, Eric
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- Self-assembled N-alkylimidazolium perfluorooctanesulfonates
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Thermostability of a smectic A phase composed of N-alkyl-imidazolium heptadecafluorooctanesulfonate was improved by the formation of nonpolar layer composed of mixed perfluoroalkyl and aliphatic chains. Copyright
- Mukai, Tomohiro,Yoshio, Masafumi,Kato, Takashi,Ohno, Hiroyuki
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- Antimicrobial activity and SAR study of new gemini imidazolium-based chlorides
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A series of 70 new 3,3′(α,ω-dioxaalkyl)bis(1- alkylimidazolium) chlorides were synthesized. They were characterized with respect to surface active properties and antimicrobial activity against the following pathogens: Staphylococcus aureus, Enterococcus faecalis, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Candida krusei, and Candida albicans. In this article, besides description of the synthesis, we characterize a set of features of these compounds, concerning their structure (described by the length of the dioxaalkan spacer and the length of the alkyl substituent in the aromatic ring) and surface active properties (critical micelle concentration, value of surface tension at critical micelle concentration, value of surface excess, molecular area of a single particle, and free energy of adsorption of molecule). Then, we present a SAR study for Staphylococcus aureus, as one of the most widespread pathogenic strains, conducted with the help of the Dominance-based Rough Set Approach (DRSA), that involves identification of relevant features and relevant combinations of features being in strong relationship with a high antimicrobial activity of the compounds. The SAR study shows, moreover, that the antimicrobial activity is dependent on the type of substituents and their position at the chloride moiety, as well as on the surface active properties of the compounds.
- Pa?kowski, ?ukasz,B?aszczyński, Jerzy,Skrzypczak, Andrzej,B?aszczak, Jan,Kozakowska, Karolina,Wróblewska, Joanna,Kozuszko, Sylwia,Gospodarek, Eugenia,Krysiński, Jerzy,S?owiński, Roman
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p. 278 - 288
(2014/03/21)
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- NHC-silver(I) complexes as chemical nucleases; Synthesis, crystal structures, and antibacterial studies
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A series of N-heterocyclic carbene (NHC) precursors, 1-methoxylethyl-3- allylimidazolium hexafluorophosphate (1), 1-ethyl-3-allylimidazolium hexafluorophosphate (2), and 1-pentyl-3-allylimidazolium hexafluorophosphate (3) were synthesized. These salts were treated with Ag2O to afford their corresponding mononuclear Ag(I)-NHC complexes, namely 1-methoxylethyl-3- allylimidazolium silver(I) hexafluorophosphate (4), 1-ethyl-3-allylimidazolium silver(I) hexafluorophosphate (5), and 1-pentyl-3-allylimidazolium silver(I) hexafluorophosphate (6), respectively. These compounds were characterized by physicochemical and spectroscopy techniques. Compounds 4 and 5 were structurally characterized by single crystal X-ray diffraction, and their stability in solution was investigated and found to be acceptable for the antibacterial studies. These new NHC precursors and their respective Ag-NHC complexes were screened for their antibacterial activities against Staphylococcus aureus (ATCC 12600) and Escherichia coli (ATCC 25922). Compounds 1-3 showed no inhibition, whereas 4-6 inhibited the growth of these bacteria. The nuclease activities of the reported compounds against plasmid DNA and RNA were assessed by gel electrophoresis, and the results indicate that complexes 5 and 6 can degrade both DNA and RNA in the absence of an oxidant.
- Haque, Rosenani A.,Asekunowo, Patrick O.,Razali, Mohd. R.,Mohamad, Faisal
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p. 194 - 204
(2014/06/09)
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- Anisotropic ionic conductivity in fluorinated ionic liquid crystals suitable for optoelectronic applications
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In this work, we report a library of thirteen fluorinated ionic liquids consisting of iodide salts of 1-alkyl-3-polyfluoroalkyl-imidazolium cations. By changing the length of the alkyl and polyfluoroalkyl pendants, we discovered that particular combinations of these result in compounds showing a mesophase. The nature and the molecular arrangement of the mesophase are characterised by polarised optical microscopy and powder X-ray diffraction analysis, among others. We demonstrate that, after the addition of I2 to generate the I-/I3- redox couple, anisotropic ionic conductivity takes place along preferential pathways in the lamellar structure of the mesophase. Notably, the addition of I2 does not suppress the mesophase temperature range, contrary to previously reported systems. Furthermore, the tendency of these materials to supercool allows the molecular arrangement in the mesophase to be retained in a solid film at ambient temperatures. Finally, we demonstrate their applicability as a quasi-solid electrolyte by preparing dye-sensitised solar cells with power conversion efficiencies comparable to the previous reports.
- Abate, Antonio,Petrozza, Annamaria,Cavallo, Gabriella,Lanzani, Guglielmo,Matteucci, Francesco,Bruce, Duncan W.,Houbenov, Nikolay,Metrangolo, Pierangelo,Resnati, Giuseppe
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p. 6572 - 6578
(2013/07/26)
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- Isoprene as lithiation mediator: Synthesis of 2-substituted 1-alkylimidazole derivatives
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The lithiation of different imidazoles bearing a primary (i.e., butyl, pentyl, dodecyl) or secondary (i.e., cyclohexyl, 1-methylheptyl) alkyl substituent on the nitrogen has been successfully achieved by means of an isoprene-mediated protocol. The subsequent reaction of the 2-lithioimidazole intermediates with different electrophiles leads to the formation of interesting 1,2-disubstituted imidazoles. Georg Thieme Verlag Stuttgart · New York.
- Martinez, Regina,Torregrosa, Rosario,Pastor, Isidro M.,Yus, Miguel
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experimental part
p. 2630 - 2638
(2012/09/07)
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- Synthesis and properties of chiral imidazolium ionic liquids with a (1R,2S,5R)-(-)-menthoxymethyl substituent
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A series of 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-alkylimidazolium salts have been synthesized, producing both hydrophilic and hydrophobic chiral imidazolium ionic liquids. Their physicochemical properties, single-crystal X-ray structures, antimicrobial activities, and antielectrostatic effects were determined and these compounds have proven to represent not only potential new solvents in asymmetric synthesis, but also effective, disinfectants with antielectrostatic activity. Given the number and diversities of the possible conformations and interionic interactions, coupled with the chiral nature of the cations, it should come as no surprise that these salts exhibit ionic liquid behavior and are so difficult to crystallize. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Pernak, Juliusz,Feder-Kubis, Joanna,Cieniecka-Ros?onkiewicz, Anna,Fischmeister, Cedric,Griffin, Scott T.,Rogers, Robin D.
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p. 879 - 892
(2008/02/12)
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- Synthesis of N-alkylated derivatives of imidazole as antibacterial agents
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N-Alkylation of imidazole, 2-methylimidazole and 2-methyl-4-nitroimidazole have been carried out to achieve effective antibacterial agents. The products were then investigated for antibacterial activity against Escherichia coil, Staphylococcus aureus and Pseudomonas aeruginosa. Antibacterial effects of 1-alkylimidazole derivatives increase as the number of carbons in alkyl chain increases up to nine carbons. Also substitution of 2-methyl and 2-methyl-4-nitro groups on imidazole ring increases the antibacterial activity.
- Khabnadideh,Rezaei,Khalafi-Nezhad,Bahrinajafi,Mohamadi,Farrokhroz
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p. 2863 - 2865
(2007/10/03)
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- Remarkable fast n-alkylation of azaheterocycles under microwave irradiation in dry media
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Under microwave irradiation a number of azaheterocycles (i.e., pyrrole, imidazole, pyrazole, indole, and carbazole) react remarkably fast with alkyl halides to give exclusively N-alkyl derivatives.
- Bogdal, Dariusz,Pielichowski, Jan,Jaskot, Krzysztof
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p. 715 - 722
(2007/10/03)
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- Pharmaceutically active imidazole derivatives
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The invention relates to a class of imidazoles substituted by cycloalkyl or cycloalkenyl which have pharmacological properties making them useful in medicine, in particular in the prophylaxis and treatment of thrombo-embolic disorders.
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