- Small-angle neutron-scattering studies of mixed micellar structures made of dimeric surfactants having imidazolium and ammonium headgroups
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Planar imidazolium cation based gemini surfactants [16-Im-n-Im-16], 2Br- (where n = 2, 3, 4, 5, 6, 8, 10, and 12), exhibit different morphologies and internal packing arrangements by adopting different supramolecular assemblies in aqueous media depending on their number of spacer methylene units (CH2)n. Detailed measurements of the small-angle neutron-scattering (SANS) cross sections from different imidazolium-based surfactant micelles in aqueous media (D2O) are reported. The SANS data, containing the information of aggregation behavior of such surfactants in the molecular level, have been analyzed on the basis of the Hayter and Penfold model for the macro ion solution to compute the interparticle structure factor S(Q) taking into account the screened Coulomb interactions between the dimeric surfactant micelles. The characteristic changes in the SANS spectra of the dimeric surfactant with n = 4 due to variation of temperature have also been investigated. These data are then compared with the SANS characterization data of the corresponding gemini micelles containing tetrahedral ammonium ion based polar headgroups. The critical micellar concentration of each surfactant micelle (cmc) has been determined using pyrene as an extrinsic fluorescence probe. The variation of cmc as a function of spacer chain length has been explained in terms of conformational variation and progressive looping of the spacer into the micellar interior upon increasing the n values. Small-angle neutron-scattering (SANS) cross sections from different mixed micelles composed of surfactants with ammonium headgroups, 16-A 0, [16-Am-n-Am-16], 2Br- (where n = 4), 16-I0, and [16-Im-n-Im-16], 2Br- (where n = 4), in aqueous media (D 2O) have also been analyzed. The aggregate composition matches with that predicted from the ideal mixing model.
- Pal, Asish,Datta, Sougata,Aswal,Bhattacharya, Santanu
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Read Online
- gemini-type imidazole surfactant with high-temperature thickening effect Wormlike micelle and application thereof
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The invention relates to gemini-type imidazole surfactant, wormlike micelle and application thereof in the technical field of surfactants, and the formula of gemini-type imidazole surfactant with the high-temperature thickening effect of the invention is [C]. n - C2 - Cn im] Br2 (n=16, 18). The gemini-type imidazole surfactant has high stability and viscoelasticity at high temperature under one-component conditions in water. The specific structure enables the wormlike micelle with high-temperature thickening effect to be formed without additives in water. And [C]n - C2 - Cn im] Br2 (n=16, 18) The concentration in the aqueous phase was 91 - 143 mmol ? L. -1 At the time of 25 - 97 °C temperature range, the system behaves as a wormlike micelle with excellent thermal stability, so that [C] of the invention is made. n - C2 - Cn im] Br2 (n=16, 18) The high-temperature vermicular micelle formed in water can be used as an oil-displacing agent for tertiary oil recovery. Soft templates for synthetic nanomaterials, lubricants, and the like.
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Paragraph 0027; 0028; 0030
(2021/11/21)
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- N-Functionalised Imidazoles as Stabilisers for Metal Nanoparticles in Catalysis and Anion Binding
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Metal nanoparticles (NPs) have physicochemical properties which are distinct from both the bulk and molecular metal species, and provide opportunities in fields such as catalysis and sensing. NPs typically require protection of their surface to impede aggregation, but these coatings can also block access to the surface which would be required to take advantage of their unusual properties. Here, we show that alkyl imidazoles can stabilise Pd, Pt, Au, and Ag NPs, and delineate the limits of their synthesis. These ligands provide an intermediate level of surface protection, for which we demonstrate proof-of-principle in catalysis and anion binding.
- Beer, Paul D.,Cookson, James,Serpell, Christopher J.
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p. 683 - 690
(2020/07/03)
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- Surface-active double-alkaline task-specific ionic liquids and preparation method thereof
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The invention relates to surface-active double-alkaline task-specific ionic liquids and a preparation method thereof. The surface-active double-alkaline task-specific ionic liquids are synthesized bythe following three-step reactions: firstly, performing coupling on imidazole and a halogenated hydrocarbon under alkaline conditions to obtain N-long chain alkyl imidazole; secondly, performing a quaterisation reaction on the N-long chain alkyl imidazole and 1-(2-chloroethyl)piperidine hydrochloride to obtain an ionic halide; and finally, performing ion exchange to obtain the target molecular hydrogen hydroxide N-long chain alkyl imidazole alkaline ionic liquids. The synthetic method provided by the invention has mild reaction conditions and simple post-treatment; and the ionic liquids not only have double functions of Lewis alkalinity and Bronst alkalinity, but also have surface active functions.
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Paragraph 0036-0039; 0046-0049; 0056-0059
(2019/08/12)
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- Molecular tunability of surface-functionalized metal nanocrystals for selective electrochemical CO2 reduction
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Organic ligands are used in homogeneous catalysis to tune the metal center reactivity; in contrast, clean surfaces are usually preferred in heterogeneous catalysis. Herein, we demonstrate the potential of a molecular chemistry approach to develop efficient and selective heterogeneous catalysts in the electrochemical CO2 reduction reaction (CO2RR). We have tailor-made imidazolium ligands to promote the CO2RR at the surface of hybrid organic/inorganic electrode materials. We used silver nanocrystals for the inorganic component to obtain fundamental insights into the delicate tuning of the surface chemistry offered by these ligands. We reveal that modifying the electronic properties of the metal surface with anchor groups along with the solid/liquid interface with tail groups is crucial in obtaining selectivities (above 90% FE for CO), which are higher than the non-functionalized Ag nanocrystals. We also show that there is a unique dependency of the CO2RR selectivity on the length of the hydrocarbon tail of these ligands, offering a new way to tune the interactions between the metal surface with the electrolyte and reactants.
- Pankhurst, James R.,Guntern, Yannick T.,Mensi, Mounir,Buonsanti, Raffaella
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p. 10356 - 10365
(2019/11/20)
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- An efficient strategy for N-alkylation of benzimidazoles/imidazoles in SDS-aqueous basic medium and N-alkylation induced ring opening of benzimidazoles
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A sustainable route for the N-1 alkylation of imidazole and benzimidazole derivatives has been developed under volatile organic solvent free condition in alkaline water-SDS system. Incorporation of SDS in the reaction medium enhances the reaction rate by suppressing the solubility issue that arises for different substrates. This method provides high yield of the alkylated product in a shorter reaction time. For reactive alkyl halides reaction proceeds at ambient temperature whereas in the cases of less reactive alkyl halides require 55–60 °C to complete alkylation process. N-alkylation induced ring opening of the heterocyclic ring in benzimidazole derivatives to multifunctional aromatic compounds were noticed at 60 °C when more than two equivalents of alkyl halide was used.
- Chakraborty, Ankita,Debnath, Sudipto,Ghosh, Tanmoy,Maiti, Dilip K.,Majumdar, Swapan
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p. 5932 - 5941
(2018/09/18)
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- Exploring the cellular uptake and localisation of phosphorescent rhenium: Fac -tricarbonyl metallosurfactants as a function of lipophilicity
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A systematic study of the cellular uptake of emissive complexes as a function of their lipophilicity is presented. Here a series of amphiphilic rhenium fac-tricarbonyl bisimine complexes bearing axial substituted imidazole or thiazole ligands, [Re(bpy)(CO)3(ImCnHm)]+ {n = 1 m = 3 (1+), n = 4 m = 9 (2+), n = 8 m = 17 (3+), n = 12 m = 25 (4+), n = 16 m = 33 (5+), n = 2 m = 3 (6+); bpy = 2,2′-bipyridine, Im = imidazole} and [Re(bpy)(CO)3(L)]+ {L = 1-mesitylimidazole, ImMes (7+), 4,5-dimethylthiazole, dmt (8+) and 4-methyl-5-thiazole-ethanol, mte (9+)} is reported. The X-ray crystal structures of 2+, 8+ and 9+ confirm the geometry and expected distribution of ligands and indicated that the plane of the imidazole/thiazole ring is approximately parallel to the long axis of the bipy ligand. Luminescence studies revealed excellent properties for their use in cell imaging with visible excitation and broad emission profiles. Their uptake in two distinct species has been examined by fluorescence imaging of the diplomonad fish parasite Spironucleus vortens (S. vortens) and rod-shaped yeast Schizosaccharomyces pombe (Schiz. pombe) as a function of their lipophilicity. The uptake of the complexes was highest for the more lipophilic 2+-5+ in both S. vortens and Schiz. pombe in which the long alkyl chain aids in crossing bilipid membranes. However, the increased lipophilicity of longer chains also resulted in greater toxicity. Localisation over the whole cell varied with differing alkyl chain lengths with complex 2+ preferentially locating to the nucleus of S. vortens, 3+ showing enhanced nuclear partitioning in Schiz. pombe, and 4+ for the remaining cell wall bound in the case of S. vortens. Interestingly, complexes of intermediate lipophilicity such as 7+ and 8+ showed reasonable uptake, proved to be non-toxic, and were capable of crossing exterior cell walls and localising in the organelles of the cells.
- Hallett, Andrew J.,Placet, Emeline,Prieux, Roxane,McCafferty, Danielle,Platts, James A.,Lloyd, David,Isaacs, Marc,Hayes, Anthony J.,Coles, Simon J.,Pitak, Mateusz B.,Marchant, Sarah,Marriott, Stephen N.,Allemann, Rudolf K.,Dervisi, Athanasia,Fallis, Ian A.
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supporting information
p. 14241 - 14253
(2018/10/25)
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- 1,1 the [...] -di-alkyl -3,3 the [...] -(2-phosphate ester -1,3-propyl) imidazole in the process for the preparation of salt compound
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The invention relates to a 1,1'-dialkyl-3,3'-(2-phosphate-1,3-propylidene)imidazolium compound and a preparation method thereof. The structural formula of the 1,1'-dialkyl-3,3'-(2-phosphate-1,3-propylidene)imidazolium compound is shown in the specification, wherein n is 6, 8, 10, 12 and 14, and the alkyl imidazole can be replaced with alkyl benzimidazole. The 1,1'-dialkyl-3,3'-(2-phosphate-1,3-propylidene)imidazolium is a amphoteric dimeric surfactant, and a concrete synthesis method comprises the following steps: synthesizing 1, 3-dichloro-2-propanol, synthesizing N-alkyl imidazole, synthesizing 1,1'-dialkyl-3,3'-(2-hydroxyl-1,3-propylidene)imidazole hydrochloride, and synthesizing 1,1'-dialkyl-3,3'-(2-phosphate-1,3-propylidene)imidazolium. The 1,1'-dialkyl-3,3'-(2-phosphate-1,3-propylidene)imidazolium compound and the preparation method are easily available in raw materials, the reaction technology conditions are easy to control, operation is simple, the product is easy to purify, and yield is high. The compound has low critical micelle concentration, and can be used as a wetting agent, an emulsifier, a foaming agent and a foam stabilizer. A molecular structure has macrocyclic cefpimizole group and phosphate ester, and thus the compound has good thermal stability, solubility, salinity resistance, temperature resistance and acid and base resistance.
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Paragraph 0079; 0080
(2016/12/07)
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- A Comprehensive Study on the Synthesis and Micellization of Disymmetric Gemini Imidazolium Surfactants
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Two groups of disymmetric Gemini imidazolium surfactants, [C14C4Cmim]Br2 (m?=?10, 12, 14) and [CmC4Cnim]Br2 (m?+?n?=?24, m?=?12, 14, 16, 18) surfactants, were synthesized and their structures were confirmed by 1H NMR and ESI–MS spectroscopy. Their adsorption at the air/water interface, thermodynamic parameters and aggregation behavior were explored by means of surface tension, electrical conductivity and steady-state fluorescence. A series of surface activity parameters, including cmc, γcmc, πcmc, pC20, cmc/C20, Γmax and Amin, were obtained from surface tension measurements. The results revealed that the overall hydrophobic chain length (Nc) for [C14C4Cmim]Br2 and the disymmetry (m/n) for [CmC4Cnim]Br2 had a significant effect on the surface activity. The cmc values decreased with an increase of Nc or m/n. The thermodynamic parameters of micellization (ΔGm θ, ΔHm θ, ΔSm θ) derived from the electrical conductivity indicated that the micellization process of [C14C4Cmim]Br2 and [CmC4Cnim]Br2 was entropy-driven at different temperatures, but the contribution of ΔHm θ to ΔGm θ was enhanced by increasing Nc or m/n. The micropolarity and micellar aggregation number (Nagg) were estimated by steady-state fluorescence measurements. The results showed that the surfactant with higher Nc or m/n can form larger micelles, due to a tighter micellar structure.
- Zhao, Xiaohui,An, Dong,Ye, Zhiwen
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p. 681 - 691
(2016/07/06)
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- Synthesis of methylal from methanol and formaldehyde catalyzed by Br?nsted acid ionic liquids with different alkyl groups
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The catalytic reaction of methanol with formaldehyde for the preparation of methylal was investigated in various Br?nsted acid ionic liquids with different carbon chain length of alkyl groups. The structures, acidities, and properties of ionic liquids were experimentally characterized and theoretically analyzed. The Br?nsted acidity-viscosity-activity correlation for the ionic liquids was studied. Among all these ionic liquids, [C6ImBS][HSO4] exhibited the best catalytic performance, which was ascribed to its strong Br?nsted acidity and low viscosity. The catalytic activity of the ionic liquid was near that of concentrated sulfuric acid. The influences of ionic liquid dosage, reaction temperature and molar ratio of methanol to formaldehyde were explored using [C6ImBS]HSO4 as the catalyst. Under the optimal conditions of n(methanol):n(formaldehyde):n(ILs) = 2.5:1:0.0258, 60 °C, and 4 h, the conversion of formaldehyde can reach 63.37%. The ionic liquid [C6ImBS]HSO4 could be reused.
- Sun, Jiahan,Li, Hansheng,Song, Haoran,Wu, Qin,Zhao, Yun,Jiao, Qingze
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p. 87200 - 87205
(2015/11/09)
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- Imidazolium salts grafted on cotton fibres for long-term antimicrobial activity
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New antimicrobial (AM) coatings based on imidazolium salts have been prepared linking the imidazolium salts to the cotton fabric using siloxane oligomers as coupling agents. Three different imidazolium salts, linked to the siloxane oligomers connected to
- Izmaylov, Boris,Di Gioia, Diana,Markova, Galy,Aloisio, Irene,Colonna, Martino,Vasnev, Valery
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- Synthesis of some functionalized ionic liquids with long chain of carbone starting from imidazole
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Synthesis of some ionic liquids ILs 3 a-b is described starting from imidazole 1. The starting material is converted under microwave irradiation to N-alkyl imidazole (1a-b) which reacted with allylbromide to give functionalized N-alkyl, N'-allyl imidazolium bromide (2a-b). Hydroboration followed by methanolysis and acid hydrolysis applied to these give the target compounds 3 a-b in good yields.
- Djellal, Ahmed,Amirat, Samia
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p. 2391 - 2394
(2016/02/27)
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- Alkyl-imidazolium glycosides: Non-ionic - Cationic hybrid surfactants from renewable resources
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A series of surfactants combining carbohydrate and imidazolium head groups were prepared and investigated on their assembly behavior. The presence of the imidazolium group dominated the interactions of the surfactants, leading to high CMCs and large molecular surface areas, reflected in curved rather than lamellar surfactant assemblies. The carbohydrate, on the other hand, stabilized molecular assemblies slightly and reduced the surface tension of surfactant solutions considerably. A comparative emulsion study discourages the use of pure alkyl imidazolium glycosides owing to reduced assembly stabilities compared with APGs. However, the surfactants are believed to have potential as component in carbohydrate based surfactant mixtures.
- Salman, Abbas Abdulameer,Tabandeh, Mojtaba,Heidelberg, Thorsten,Hussen, Rusnah Syahila Duali,Ali, Hapipah Mohd
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supporting information
p. 28 - 33
(2015/05/27)
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- A delocalizable cationic headgroup together with an oligo-oxyethylene spacer in gemini cationic lipids improves their biological activity as vectors of plasmid DNA
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Lipoplex nano-aggregates constituted of plasmid DNA (pDNA) pEGFP-C3 and mixed cationic liposomes, consisting of several percentages of a gemini cationic lipid (GCL) of the 1,2-bis(hexadecyl imidazolium) oxyethylene series, referred to as (C16Im)2(C2O)n, with oxyethylene spacers (n = 1, 2 or 3) between the imidazolium cationic groups and the DOPE zwitterionic helper lipid, have been characterized by various biophysical and biological approaches carried out at several GCL compositions (α), and either the mass or the effective charge ratio of the lipoplex. The electrochemical study by ζ-potential confirms that the three GCLs yield a 10% lower effective charge than the nominal one, while compacted pDNA yields only a 25% effective negative charge. The SAXS study reveals, irrespective of the spacer length (n) and effective charge ratio (ρeff), the presence of two lamellar structures, i.e., one (Lα,main) in the whole GCL composition and another (Lα,DOPE,rich) with higher periodicity values that coexists with the previous one at low GCL composition (α = 0.2). The cryo-TEM analysis shows two types of multilamellar structures consisting of cationic lipidic bilayers with pDNA sandwiched between them: a cluster-type (C-type) at low α = 0.2 and a fingerprint-type (FP-type) at α ≥ 0.5, both with similar interlamellar spacing (d) in agreement with the Lα,main structure determined by SAXS. Transfection efficacies (TEs) of each lipid mixture were determined in four different cell lines (HEK293T, HeLa, Caco-2 and A549) at several α and ρeff values in the absence and presence of serum (FBS). The optimized formulations (α = 0.2 and ρeff = 2.0) substantially transfect cells much better than a commercial transfection reagent, Lipofectamine 2000 and previously studied efficient lipoplexes containing other cationic head groups or spacers both in the absence and presence of serum. The activity of optimized formulations may be attributed to the combination of several factors, such as: (a) the fusogenic character of DOPE which results in higher fluidity of the lipoplexes at α = 0.2, (b) the coexistence of two lamellar structures at α = 0.2 that synergizes the TE of these lipid vectors, and mainly (c) the higher biocompatibility of the GCLs reported in this work due to the presence of two imidazolium cationic groups together with an oligo-oxyethylene spacer. The length of the spacer in the GCL seems to have less impact, although (C16Im)2(C2O)n/DOPE-pDNA lipoplexes with n = 1 and 3 show higher gene transfection than n = 2. All the optimum formulations reported herein are all highly efficient with negligible levels of toxicity, and thus, may be considered as very promising gene vectors for in vivo applications. This journal is
- Kumar, Krishan,Barrn-Berdn, Ana L.,Datta, Sougata,Muoz-beda, Mnica,Aicart-Ramos, Clara,Kondaiah, Paturu,Junquera, Elena,Bhattacharya, Santanu,Aicart, Emilio
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p. 1495 - 1506
(2015/03/04)
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- Synthesis of polyoxymethylene dimethyl ethers from methylal and trioxane catalyzed by Br?nsted acid ionic liquids with different alkyl groups
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Br?nsted acid ionic liquids with different alkyl group carbon chain lengths and an alkane sulfonic acid group were synthesized through bromoalkane, imidazole and 1,4-butane sultone as raw materials. The structures and properties of the ionic liquids were experimentally characterized. Catalytic reaction of methylal (DMM) with trioxane (TOX) for preparation of polyoxymethylene dimethyl ethers (PODMEn, CH3O(CH2O)nCH3, where n > 1) was investigated in various Br?nsted acid ionic liquids with different carbon chain length of alkyl groups. The carbon chain length of alkyl groups and activity correlation for the ionic liquids was studied. It was found that the structures of ionic liquids were consistent with the designed structure and their purities were high. They possessed high thermal stability and wide liquid range. The hydrophobicity of ionic liquids became stronger with the increase of carbon chain length. With increasing the carbon chain length of ionic liquids, the selectivity of PODME3-8 is increased at first and then decreased. Among all the ionic liquids, [C6ImBS][HSO4] shows the best catalytic performance and the selectivity of PODME3-8 is 57.85%.
- Wu, Qin,Li, Weijiao,Wang, Min,Hao, Yu,Chu, Tonghua,Shang, Jiqing,Li, Hansheng,Zhao, Yun,Jiao, Qingze
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p. 57968 - 57974
(2015/07/20)
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- Temperature-responsive proton-conductive liquid crystals formed by the self-assembly of zwitterionic ionic liquids
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In the present study, we synthesized a series of ionic liquids by mixing amphiphilic imidazolium-type zwitterions with sulfonic acids containing different substituent groups. Nanostructured proton conductors having hexagonal and cubic structures were constructed by the self-assembly of these zwitterionic ionic liquids. These nanostructured proton conductors exhibited an assembled-structure dependent proton conduction behavior. The introduction of highly ordered liquid crystal structures efficiently improved ionic conductivity, suggesting the induction of proton conduction through a hopping mechanism. Temperature-responsive ionic conductivity behavior based on phase transition within the self-assembled liquid crystal structures was also observed.
- Gao, Xinpei,Lu, Fei,Dong, Bin,Zhou, Tao,Liu, Yizhi,Zheng, Liqiang
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p. 63732 - 63737
(2015/08/11)
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- Imidazolium-based zwitterionic surfactants: Characterization of normal and reverse micelles and stabilization of nanoparticles
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This paper presents the physicochemical properties of micellar aggregates formed from a series of zwitterionic surfactants of the type 3-(1-alkyl-3-imidazolio)propane-sulfonate (ImS3-n), with n = 10, 12, 14, and 16. The ImS3-n dipolar ionic surfactants represent a versatile class of dipolar ionic compounds, which form normal and reverse micelles. Furthermore, they are able to stabilize nanoparticles in water and in organic media. Aqueous solubility is too low at room temperature to allow characterization of micellar aggregates but increases with addition of salts, allowing determination of aggregation number and cmc. As expected, these parameters depend on the length of the alkyl chain, and cmc values follow Klevens equation. In the presence of NaClO4, all ImS3-n micelles become anionoid by incorporating ClO4- on the micellar interface. A special feature of these surfactants is the ability to form reverse micelles and solubilize copious amounts of saline solutions in chloroform. 1H NMR and infrared spectroscopic evidence showed that the maximum water to surfactant molar ratio w0 achievable depends on the concentration and type of salt dissolved. Reverse micelles of the ImS3-n surfactants can be used to stabilize metallic nanoparticles, whose size may be tuned by the amount of water dissolved.
- Souza, Franciane D.,Souza, Bruno S.,Tondo, Daniel W.,Leopoldino, Elder C.,Fiedler, Haidi D.,Nome, Faruk
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p. 3587 - 3595
(2015/04/14)
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- CO2/N2 triggered Switchable surfactants with imidazole group
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In order to overcome the hydrolysis of 2-alkyl-1-hydroxyethyl imidazoline and its unsatisfactory emulsification-demulsification switchability to water-alkane, the long-chain N-alkylimidazole compounds were synthesized by n-octyl bromide, n-decyl bromide, n-dodecyl bromide, n-tetradecyl bromide and n-hexadecyl bromide with imidazole, respectively and characterized by MS, 1H NMR and FTIR. The long-chain N-alkylimidazole compounds can be reversibly transformed into charged surfactants by exposure to CO2. Surface tension values indicated that N-alkylimidazolium bicarbonates had excellent surface activity compared with corresponding conventional surfactants with a lower γ CMC. The surface behaviors of the five surfactants can be illustrated by A min. Five conductivity cycles by bubbling CO2 and N2 alternately indicated that these surfactants could be switched by CO2 reversibly and repeatedly. Emulsions were repeatedly stabilized for five cycles by N-alkylimidazolium bicarbonate and broken by bubbling N2 through the solutions to reverses the reaction, releasing CO2.
- Chai, Mingfeng,Zheng, Zhibo,Bao, Lei,Qiao, Weihong
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p. 383 - 390
(2014/05/20)
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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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- Peroxopolyoxotungsten-based ionic hybrid as a highly efficient recyclable catalyst for epoxidation of vegetable oil with H2O2
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A peroxopolyoxotungsten-based ionic hybrid was synthesized by anion-change of peroxopolyoxometalate (POM) PW4O243- with dicationic long-chain alkyl imidazolium ionic liquids. The characterization was conducted by FT-IR, TGA, 1H-NMR and CHN Elemental analyses. Its catalytic performance was evaluated by the epoxidation of soybean oil with H2O2 under solvent-free condition, including testing of organic cations influence, catalytic reusability and reaction conditions. The catalyst was proved to be a highly efficient recyclable catalyst for epoxidation of various vegetable oils with H2O2, showing high H 2O2 utilization efficiency, high catalytic activity, convenient recovery and good reuse ability.
- Wu, Jianghao,Jiang, Pingping,Qin, Xiaojie,Ye, Yuanyuan,Leng, Yan
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p. 1675 - 1680
(2014/07/07)
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- Symmetrical 1, 3-Dialkylimidazolium Based Ionic Liquid Crystals
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The synthesis and characterization for a series of symmetrical 1, 3-dialkylimidazolium salts with different chain lengths and counter anions together with their 1-alkylimidazole precursors are described. Liquid crystal (LC) properties of these salts are studied. Images under polarizing optical microscopy show focal conic texture together with homeotropic domains. A smectic A mesophase, typical for rod-like imida-zolium salts, is assigned. Studies from powder X-ray diffraction suggest a lamellar structure with non-interdigitated monolayer arrangement for the LC salts in the mesophase. In addition, a short note on the structure and property relationship for rod-like, discor fan-like, and dendritic shaped imidazolium ionic liquid crystals (ImILCs) forming smectic, columnar, and cubic phase is briefly summarized. Acomparison of minimum alkyl chain length needed for 1-alkyl-3-methyl and symmetrical 1, 3-dialkyl ImILCs to exhibit LC behavior is addressed.
- Rohini, Rondla,Lee, Ching-Kuan,Lu, Jung-Tang,Lin, Ivan J.B.
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p. 745 - 754
(2013/11/06)
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- Synthesis and characterization of imidazolium telechelic poly(butylene terephthalate) for antimicrobial applications
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Poly(butylene terephthalate) ionomers with imidazolium groups selectively located as end-groups (telechelic) have been prepared by melt polycondensation adding a hydroxyl derivatized imidazolium salt at the beginning of the polymerization process. The des
- Colonna, Martino,Berti, Corrado,Binassi, Enrico,Fiorini, Maurizio,Sullalti, Simone,Acquasanta, Francesco,Vannini, Micaela,Di Gioia, Diana,Aloisio, Irene,Karanam, Sreepadaraj,Brunelle, Daniel J.
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p. 133 - 141
(2013/01/15)
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- NANOPARTICLE/DISPERSANT COMPLEX, NANOPARTICLE DISPERSION LIQUID, AND NANOPARTICLE/MATRIX-MATERIAL COMPLEX
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Provided are a nanoparticle/dispersant complex having excellent dispersibility and long-term stability in a dispersion medium, a production method therefor, and a nanoparticle dispersion liquid and a nanoparticle/matrix-material complex which are colorless and transparent even at high concentrations. In the nanoparticle/dispersant complex, a nanoparticle is covered with a dispersant containing a heterocyclic cationic group and one of an oxo acid group containing a sulfur atom or a phosphorus atom and an anion moiety of the oxo acid group; in the nanoparticle dispersion liquid, the nanoparticle/dispersant complex is dispersed into a dispersion medium; in the nanoparticle/matrix-material complex, the nanoparticle/dispersant complex is dispersed into a matrix material; and the production method for a nanoparticle/dispersant complex comprises forming, under a presence of the dispersant, a nanoparticle covered with the dispersant from a nanoparticle precursor.
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- Pd(ii) immobilized on mesoporous silica by N-heterocyclic carbene ionic liquids and catalysis for hydrogenation
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In this work we synthesized Pd(ii) immobilized on mesoporous silica by N-heterocyclic carbene (NHC) ionic liquids (ILs) with different alkyl chain lengths. The catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), low-angle X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen sorption. The catalysts were used for the hydrogenation of alkenes and allyl alcohol. The results indicated that the catalysts were very active, selective, and stable. The selectivity for the hydrogenation of allyl alcohol to 1-propanol increased with the increase of the alkyl chain length of the ILs. The effect of supercritical CO2 (scCO2) on the hydrogenation of allyl alcohol was also studied, and it was demonstrated that scCO2 could enhance the selectivity of the reaction considerably. The XPS study showed that the valence of Pd(ii) remained unchanged under hydrogenation conditions. the Owner Societies.
- Liu, Gang,Hou, Minqiang,Wu, Tianbin,Jiang, Tao,Fan, Honglei,Yang, Guanying,Han, Buxing
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experimental part
p. 2062 - 2068
(2011/09/20)
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- Effects of a flexible alkyl chain on a ligand for CuAAC reaction
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Imidazole derivatives substituted by a normal alkyl group are shown to be efficient as a ligand for the copper(Δ)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. An alkyl chain on the imidazole ligands shows an efficient steric effect and benefits the reaction. Such functionalities of an alkyl chain allow a rapid CuAAC reaction of even a bulky alkyne, which has been difficult to perform under conventional conditions.
- Asano, Keisuke,Matsubara, Seijiro
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supporting information; experimental part
p. 4988 - 4991
(2010/12/25)
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- Amphiphilic organocatalyst for schotten-baumann-type tosylation of alcohols under organic solvent free condition
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A Tosylation of primary alcohol with tosyl chloride was performed effectively with an W-hexadecylimidazole catalyst in water containing K 2CO3 aggregation of the catalyst carrying a hydrophobic methylene chain worked as a substitute for organic solvent.
- Asano, Keisuke,Matsubara, Seijiro
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supporting information; experimental part
p. 1757 - 1759
(2009/09/06)
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- Morita-baylis-hillman reaction on water without organic solvent, assisted by a 'catalytic' amount of amphiphilic imidazole derivatives
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A Morita-Baylis-Hillman (MBH) reaction using water as a solvent without any organic solvent can be performed by using an amphiphilic N-alkylimidazole. This reaction is accelerated by the addition of water and is the first example of a 'catalytic' MBH reaction without organic solvent in the presence of water.
- Asano, Keisuke,Matsubara, Seijiro
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experimental part
p. 3219 - 3226
(2010/02/28)
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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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- Micelle effects of functionalized surfactants, 1-cetyl-3-(2-hydroxyiminopropyl)imidazolium halides, in reactions with p-nitrophenyl p-toluenesulfonate, diethyl p-nitrophenyl phosphate, and ethyl p-nitrophenyl ethylphosphonate
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1-Cetyl-3-(2-hydroxyiminopropyl)imidazolium chloride and bromide were synthesized for the first time. These compounds are functionalized zwitterionic surfactants which give rise to micelle formation in aqueous solution. Kinetic and thermodynamic analysis of nucleophilic cleavage of p-nitrophenyl p-toluene-sulfonate, diethyl p-nitrophenyl phosphate, and ethyl p-nitrophenyl ethylphosphonate in the presence of 1-cetyl-3-(2-hydroxyiminopropyl)imidazolium halide micelles showed that the latter are powerful nucleophilic reagents whose kinetic behavior can be described in terms of a simple pseudophase distribution model. The efficiency of substrate solubilization with zwitterionic surfactant micelles and the reactivity of the oximate fragment in the micelle phase were estimated on a quantitative level. The observed acceleration of SN2 reactions with the examined p-nitrophenyl esters relative to analogous reactions of zwitterionic 1-methyl-3-(2-hydroxyiminopropyl)imidazolium halides is, respectively, 12800, 550, and 900 times; it is explained mainly by increased concentration of the reactants in micelles.
- Simanenko,Popov,Karpichev,Prokop'eva,Savelova,Bunton
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p. 1314 - 1325
(2007/10/03)
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- Formation and Deposition of Langmuir Films of Binary and Ternary Systems
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Long chained alkylheteroaromatic compounds such as: 3-n-alkylpyrroles, 1-n-alkylimidazoles, phenylhydrazones of 3-n-alkanoylpyrrole and poly(3-n-alkylthiophenes) with 12 to 18 carbon atoms in the alkyl chain were synthesized as materials for formation of Langmuir and Langmuir-Blodgett films by both individual species as well as by mixtures. It was shown that a positive synergy exists in binary and ternary mixtures containing poly(3-n-alkylthiophenes) resulting in formation of good-quality film on aqueous surface. Several compounds were found to be good films builders for poly(3-n-alkylthiophenes) facilitating the film transfer onto solid surfaces. Among the species examined the best builder was 3-n-octadecylpyrrole. Key words: Langmuir-Blodgett films, poly(3-n-alkylthiophenes), alkylpyrroles, alkylimidazoles, synthesis
- Kucharski, S.,Janik, R.,Bryjak, M.,Bienkowski, M.,Chyla, A.,Sworakowski, J.
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p. 447 - 460
(2007/10/02)
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- Alkylation of imidazole by solid-liquid phase transfer catalysis in the absence of solvent
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Phase Transfer Catalysis in the absence of solvent is described as a useful and general method for the selective N-alkylation of imidazole. In all cases high yields are obtained while quaternization is avoided.
- Diez-Barra,De La Hoz,Sanchez-Migallon,Tejeda
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p. 1783 - 1786
(2007/10/02)
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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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p. 449 - 454
(2007/10/02)
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