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101.
Ryohei Yoshisaki Dr. Shinya Kimura Dr. Masashi Yokoya Prof. Dr. Masamichi Yamanaka 《化学:亚洲杂志》2021,16(14):1937-1941
Maltose is a ubiquitous disaccharide produced by the hydrolysis of starch. Amphiphilic ureas bearing hydrophilic maltose moiety were synthesized via the following three steps: I) construction of urea derivatives by the condensation of 4-nitrophenyl isocyanate and alkylamines, II) reduction of the nitro group by hydrogenation, and III) an aminoglycosylation reaction of the amino group and the unprotected maltose. These amphiphilic ureas functioned as low molecular weight hydrogelators, and the mixtures of the amphipathic ureas and water formed supramolecular hydrogels. The gelation ability largely depended on the chain length of the alkyl group of the amphiphilic urea; amphipathic urea having a decyl group had the highest gelation ability (minimum gelation concentration=0.4 mM). The physical properties of the supramolecular hydrogels were evaluated by measuring their thermal stability and dynamic viscoelasticity. These supramolecular hydrogels underwent gel-to-sol phase transition upon the addition of α-glucosidase as a result of the α-glucosidase-catalyzed hydrolysis of the maltose moiety of the amphipathic urea. 相似文献
102.
Makoto Shimizu Takato Kawamura Shinya Fukumoto Isao Mizota Yusong Zhu 《Journal of heterocyclic chemistry》2021,58(3):751-756
The ketene silyl acetal derived from ethyl 2-benzyltetrahydroisoquinoline-1-carboxylate undergoes a rapid oxidation reaction with N-bromosuccinimide to form 3,4-dihydroisoquinolinium ion, which reacts with Grignard reagents to give 1,1-disubstituted tetrahydroisoquinolines in good yields. 相似文献
103.
Development of a New Benzylating Reagent Spontaneously Releasing Benzyl Cation Equivalents at Room Temperature 下载免费PDF全文
Dr. Kohei Yamada Yuichi Tsukada Yukiko Karuo Dr. Masanori Kitamura Prof. Dr. Munetaka Kunishima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(38):12274-12278
A new O‐benzylating reagent, that is, 4‐(4,6‐diphenoxy‐1,3,5‐triazin‐2‐yl)‐4‐benzylmorpholinium trifluoromethanesulfonate (DPT‐BM), has been developed. Benzyl cation equivalents are generated from DPT‐BM by dissolving the compound in a solvent at room temperature under non‐acidic conditions. The benzylation of various alcohols by using a combination of DPT‐BM and magnesium oxide provided the benzyl ethers in good yields. 相似文献
104.
Prof. Yutaka Maeda Yuhei Hasuike Prof. Kei Ohkubo Atsushi Tashiro Shinya Kaneko Masayuki Kikuta Dr. Michio Yamada Prof. Tadashi Hasegawa Prof. Takeshi Akasaka Dr. Jing Zhou Prof. Jing Lu Prof. Shigeru Nagase Prof. Shunichi Fukuzumi 《Chemphyschem》2014,15(9):1821-1826
This report describes the photochemical behavior of single‐walled carbon nanotubes (SWNTs) in the presence of propylamine. The SWNTs are characterized by absorption and Raman spectroscopy. The spectral changes due to photoirradiation indicate that reactions occur predominantly with the metallic SWNTs and small‐diameter SWNTs. The detection of amine radicalcation species by ESR spectroscopy reveals photoinduced electron transfer from the amine to the excited SWNTs. After exposure of the photoirradiated SWNTs to air, the characteristic spectra were recovered, except for that of the small‐diameter SWNTs. The results suggest that, after photoreduction of the SWNTs, subsequent selective sidewall functionalization of the small‐diameter SWNTs occurs. 相似文献
105.
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107.
Shinya Teramachi 《Macromolecular Symposia》1996,110(1):217-229
The chemical composition distributions (CCDs) of poly(methyl methacrylate)-graft-polystyrene samples prepared from the polystyrene macromonomers having methacryloyl and p-vinylbenzyl end-groups were determined by high-performance liquid chromatography (HPLC) based on reversed-phase and normal-phase adsorption modes. The CCDs determined by both modes were in good agreement with one another, indicating that the effect of the molecular weight distribution on the CCD is negligible. The results demonstrated the features of the CCDs in agreement with the theoretical predictions and the strong effect of the intrinsic reactivity of the end-group on the copolymerization reactivity of the macromonomer. 相似文献
108.
Mengxing Cui Ryuichi Murase Yongbing Shen Tetsu Sato Shohei Koyama Kaiji Uchida Tappei Tanabe Shinya Takaishi Masahiro Yamashita Hiroaki Iguchi 《Chemical science》2022,13(17):4902
Electrical conduction among metallocycles has been unexplored because of the difficulty in creating electronic transport pathways. In this work, we present an electrocrystallization strategy for synthesizing an intrinsically electron-conductive metallocycle, [Ni6(NDI-Hpz)6(dma)12(NO3)6]·5DMA·nH2O (PMC-hexagon) (NDI-Hpz = N,N′-di(1H-pyrazol-4-yl)-1,4,5,8-naphthalenetetracarboxdiimide). The hexagonal metallocycle units are assembled into a densely packed ABCABC… sequence (like the fcc geometry) to construct one-dimensional (1D) helical π-stacked columns and 1D pore channels, which were maintained under the liberation of H2O molecules. The NDI cores were partially reduced to form radicals as charge carriers, resulting in a room-temperature conductivity of (1.2–2.1) × 10−4 S cm−1 (pressed pellet), which is superior to that of most NDI-based conductors including metal–organic frameworks and organic crystals. These findings open up the use of metallocycles as building blocks for fabricating conductive porous molecular materials.Intrinsically electron-conductive metallocycle was synthesized. π-Radicals play a key role in constructing π-stacked columns among molecular hexagons and achieving high electrical conductivity over 10−4 S cm−1 in polycrystalline pellet. 相似文献
109.
We prove that every k-connected graph (k ≥ 5) has an even cycle C such that G-V (C) is still (k-4)-connected. The connectivity bound is best possible. 相似文献
110.
Tae-Ho Kim Masakazu Saito Masaya Matsuoka Shinya Tsukada Kiyohisa Wada Masakazu Anpo 《Research on Chemical Intermediates》2010,36(5):453-461
It was found that the photoelectrochemical performance and photocatalytic activity of rod-type TiO2 electrodes were affected by various post-calcination treatments, for example, calcination in NH3 or under vacuum. Post-calcination treatment in NH3 at 773 K was particularly effective in increasing the photoelectrochemical performance and photocatalytic activity of rod-type
TiO2 electrodes. A unique photoelectrochemical circuit was constructed by connecting a rod-type TiO2 electrode to a Pt electrode through a silicon solar cell in which the negative bias was applied on the rod-type TiO2 electrode. It was found that the photoelectrochemical circuit can effectively oxidize ethanethiol in water into CO2. 相似文献