- Developing design tools for introducing and tuning structural order in ionic liquids
-
Ionic liquids (ILs) are receiving growing interest as highly tunable, multifunctional materials. Remarkably for liquids, they tend to display a high level of structural order. This structural order may even lead to the formation of mesophases such as liquid crystals (LCs). Imidazolium compounds are by far the most popular ILs, because they offer a widely versatile platform for property tuning. To investigate what is driving structural order in imidazolium-based ILs a series of asymmetrical 1-dodecyl-2-methyl-3-alkylimidazolium bromides, [C12C1Cnim][Br] withn= 0-12 have been synthesized, fully characterized and their structures and properties compared with the analogous 1-dodecyl-3-alkylimidazolium as well as the 1,2,3-triazolium bromides. The aim is to examine the influence of the replacement of the most acidic 2-H proton on the imidazolium head group by methylation on the properties and structure of ILs. For all compounds, except for compounds with butyl- and hexyl-chains as well as the protonated species, mesophase formation can be observed. Obviously, the simple presence of long alkyl chains such as dodecyl (a design concept frequently put forward in the literature) is not sufficient to support mesophase formation alone. Rather, for the formation of a liquid crystalline phase, a balance between attractive van der Waals forces, hydrogen bonds, and electrostatic interactions is required. Data from temperature-dependent small-angle X-ray scattering (SAXS) and polarizing optical microscopy (POM) suggest three different cation conformations for the studied [C12C1Cnim][Br]: cations with 0 ≤n≤ 4 exhibit a near-linear conformation; for 5 ≤n≤ 10 a V-shape is adopted, and forn= 11 or 12 a U-shape is found. We demonstrated that the structural possibility for an interdigitation of the long chains is an influential factor for the formation of a mesophase.
- Renier, Olivier,Bousrez, Guillaume,Yang, Mei,H?lter, Milena,Mallick, Bert,Smetana, Volodymyr,Mudring, Anja-Verena
-
-
Read Online
- Imidazolium-functionalized β-cyclodextrin as a highly recyclable multifunctional ligand in water
-
We describe here the synthesis and the catalytic properties of a novel dodecyl-imidazolium modified β-cyclodextrin as a self-assembled catalytic system (Fig. 1) in neat water for an effective Suzuki-Miyaura reaction. The introduction of the dodecyl-imidazolium motif on the primary face of the β-cyclodextrin allowed the development of a green highly recyclable catalytic system for reactions in an aqueous environment. We present the application of this system to the Suzuki-Miyaura coupling without the use of a co-solvent or stabilizing phosphine ligands in aqueous media. The catalytic system is highly recyclable, allowing the reuse of the palladium catalyst in subsequent catalytic runs without loss of activity. This journal is the Partner Organisations 2014.
- Kairouz, Vanessa,Schmitzer, Andreea R.
-
supporting information
p. 3117 - 3124
(2014/06/10)
-
- Synthesis of N-alkylated derivatives of imidazole as antibacterial agents
-
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
-
p. 2863 - 2865
(2007/10/03)
-
- Identification and characterization of a potent antibacterial agent, NH125 against drug-resistant bacteria
-
New imidazole compounds were synthesized to develop a novel and effective antibacterial agent (1-benzyl-3-cetyl-2-methylimidazolium iodide, NH125). In vitro experiments demonstrated that NH125 effectively inhibited a number of different histidine protein
- Yamamoto, Kaneyoshi,Kitayama, Takashi,Ishida, Noriyasu,Watanabe, Takafumi,Tanabe, Hiroyuki,Takatani, Masahiro,Okamoto, Tadashi,Utsumi, Ryutaro
-
p. 919 - 923
(2007/10/03)
-
- Process for preparing 1-alkylimidazoles
-
Imidazoles are alkylated at the 1-position by adding an alkyl halide a mixture comprising an imidazole, a non-reactive aromatic solvent and a base at temperature of from about 75° C. to about 115° C. and then maintaining the temperature for a period of time sufficient to produce the 1-alkylimidazole and then separating any inorganic material from the product.
- -
-
-
- Liposomal Heme as Oxygen Carrier under Semi-physiological Conditions
-
A meso-5,10,15,20-tetra(o-pivalamidophenyl)porphyrinatoiron(II) complex of a 2-methylimidazole, substituted in the 1-position with a hydrophobic group, was incorporated into a lipid bilayer of phosphatidylcholine (liposomal heme).The liposomal heme reversibly bound molecular oxygen in neutral aqueous media at 37 deg C, and the half-life of the oxygen adduct was half a day.The oxygen-binding affinity (p1/2) for the liposomal heme was ca. 50 mmHg, which is similar to that of hemoglobin in blood.The incorporation and structure of the liposomal heme were confirmed by physico-chemical methods, which indicated that the hydrophobic environment of the inner region of liposome protected the oxygen adduct from its proton-driven oxidation.
- Tsuchida, Eishun,Nishide, Hiroyuki,Yuasa, Makoto,Hasegawa, Etsuo,Matsushita, Yoh-ichi
-
p. 1147 - 1152
(2007/10/02)
-