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1.
Control over Nanostructures and Associated Mesomorphic Properties of Doped Self‐Assembled Triarylamine Liquid Crystals 下载免费PDF全文
Dr. Yuya Domoto Dr. Eric Busseron Prof. Dr. Mounir Maaloum Dr. Emilie Moulin Prof. Dr. Nicolas Giuseppone 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1938-1948
We have synthesized a series of triarylamine‐cored molecules equipped with an adjacent amide moiety and dendritic peripheral tails in a variety of modes. We show by 1H NMR and UV/Vis spectroscopy that their supramolecular self‐assembly can be promoted in solution upon light stimulation and radical initiation. In addition, we have probed their molecular arrangements and mesomorphic properties in the bulk by integrated studies on their film state by using differential scanning calorimetry (DSC), variable‐temperature polarizing optical microscopy (VT‐POM), variable‐temperature X‐ray diffraction (VT‐XRD), and atomic force microscopy (AFM). Differences in the number and the disposition of the peripheral tails significantly affect their mesomorphic properties associated with their lamellar‐ or columnar‐packed nanostructures, which are based on segregated stacks of the triphenylamine cores and the lipophilic/lipophobic periphery. Such structural tuning is of interest for implementation of these soft self‐assemblies as electroactive materials from solution to mesophases. 相似文献
2.
Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis
Yuya Nakatsuji Yusuke Kobayashi Yoshiji Takemoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(40):14253-14257
The direct 2‐deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2‐deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2‐deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2‐deoxyglycosylation of amide groups using a newly designed Brønsted acid catalyst under mild conditions. Through mechanistic investigations, we discovered that the amide group can inhibit acid catalysts, and the inhibition has made the 2‐deoxyglycosylation reaction difficult. Diffusion‐ordered two‐dimensional NMR spectroscopy analysis implied that the 2‐chloroazolium salt catalyst was less likely to form aggregates with amides in comparison to other acid catalysts. The chlorine atom and the extended π‐scaffold of the catalyst played a crucial role for this phenomenon. This relative insusceptibility to inhibition by amides is more responsible for the catalytic activity than the strength of the acidity. 相似文献
3.
Dr. Masaru Kondo Dr. Shinobu Takizawa Yuzhao Jiang Prof. Dr. Hiroaki Sasai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9866-9869
The Mills reaction and cyclization of readily available 2-aminobenzyl alcohols and nitrosobenzenes using thionyl bromide provided 2H-indazoles in up to 88 % yields. In the metal-free process, acetic acid played a crucial role for the both Mills reaction and cyclization. A brominated 2H-indazole could also be obtained through the one-pot sequence. 相似文献
4.
Selective oxidation of an AlInAs layer was investigated for enhancement of magneto-optic effect in an optical isolator. Twelve times nonreciprocal phase shift enhancement was estimated from a measured AlInAs-oxide refractive index. 相似文献
5.
Makoto Kume Yuya Maki Bungo Ochiai Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2006,44(24):7040-7053
Spiro orthocarbonate (SOC) monomers having either an exomethylene group {3,3‐dimethyl‐9‐methylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane (ExoSOC)} or an allyl group {9‐allyl‐3,3‐dimethyl‐1,5,7,11‐tetraoxaspiro[5.5]undecane (AllylSOC)} were radically copolymerized with vinyl monomers at several feed ratios to obtain the corresponding copolymers having SOC moieties in the side chain. The obtained copolymers were crosslinked via the double ring‐opening polymerization of the SOC moieties by a treatment with boron trifluoride etherate. The volume changes during the crosslinking of the copolymers were evaluated by density measurements with a gas pycnometer. As the SOC moiety composition increased, the volume shrinkage during the crosslinking was suppressed, and that finally changed into volume expansion. The volume changes during the crosslinking of the copolymers from AllylSOC were slightly larger than those of the copolymers from ExoSOC. The higher volume expansions in the crosslinking of AllylSOC‐based copolymers were ascribable to the lower steric hindrance around the SOC moieties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7040–7053, 2006 相似文献
6.
Yoshiki Chujo Kenji Kohno Noriyuki Usami Yuya Yamashita 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):1883-1890
Amphiphilic block copolymers, i.e., poly(methyl methacrylate)-b-poly(2-dimethylethylammoniumethyl methacrylate), were synthesized by the reaction between two prepolymers. Carboxyl-terminated poly(methyl methacrylate) and hydroxyl-terminated poly(2-dimethylaminoethyl methacrylate) were prepared by radical polymerization of the corresponding monomers in the presence of thioglycolic acid and 2-mercaptoethanol as a chain transfer agent, respectively. Two condensation methods, i.e., DCC and the acid chloride method, were used for the reactions of these prepolymers. The subsequent quarternization produced the amphiphilic block copolymers. Surface property of poly(methyl methacrylate) films containing this amphiphilic block copolymer was examined by measuring contact angles for water. The addition of only 0.5 wt% of the block copolymer was sufficient to make poly(methyl methacrylate) surfaces hydrophilic. The block copolymer formed a polymeric micelle in acetone–water mixed solvent. 相似文献
7.
Itsuki Shindachi Hiroshi Hanaki Ryo Sasai Tetsuya Shichi Tatsuto Yui Katsuhiko Takagi 《Research on Chemical Intermediates》2007,33(1-2):143-153
Diarylethene derivatives (DE) covalently bonded to silanol oxygens of layered silicate surfaces, i.e., magadiite (Mag), were synthesized and investigated for their photochromic behavior. The DE-Mag layered hybrids were found to undergo reversible color change by alternating UV and visible light irradiation. A more highly efficient, reproducible photochromic behavior was realized with DE-Mag than with a corresponding DE-Si possessing silyl substituents on DE in place of the Mag surface. Moreover, the present covalently bonded DE exhibited an improvement over DE hybrids incorporated in layered double hydroxide (LDH) clays, in which the repetitive photochromic behavior decreased during alternating irradiation, due to the accumulation of the photochemically inert parallel isomers of DE. 相似文献
8.
Yoshiki Chujo Tetsuya Nakamura Yuya Yamashita 《Journal of polymer science. Part A, Polymer chemistry》1990,28(1):59-65
Mercapto-16-crown-5 was prepared starting from tetraethyleneglycol and 3-chloro-2-chloromethyl-1-propene. Radical polymerization of methyl methacrylate was carried out in the presence of mercapto-16-crown-5 as a chain transfer agent to give crown ether-terminated poly(methyl methacrylate). The end crown group was characterized by IR and 1H-NMR spectra. Sodium cation was selectively extracted by this crown-containing polymer. The molecular weight of the obtained polymer had influence upon the ability of extraction of sodium cation. 相似文献
9.
Tetsuo Suami Hiroaki Sasai Kazuhiro Matsuno Nobuo Suzuki Yoshimasa Fukuda Osamu Sakanaka 《Tetrahedron letters》1984,25(40):4533-4536
Tunicamycins and their eight analogs have been synthesized by condensation of a N-acetyl-D-glucosamine derivative and an anomeric chloride of tunicaminyl uracil, followed by deprotections and N-acylation. 相似文献
10.
Large-scale separation of metallic and semiconducting single-walled carbon nanotubes 总被引:6,自引:0,他引:6
Maeda Y Kimura S Kanda M Hirashima Y Hasegawa T Wakahara T Lian Y Nakahodo T Tsuchiya T Akasaka T Lu J Zhang X Gao Z Yu Y Nagase S Kazaoui S Minami N Shimizu T Tokumoto H Saito R 《Journal of the American Chemical Society》2005,127(29):10287-10290
In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way. 相似文献