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101.
Dr. Ryo Tsunashima Yoshifumi Iwamoto Yusuke Baba Chisato Kato Katsuya Ichihashi Dr. Sadafumi Nishihara Prof. Katsuya Inoue Prof. Katsuya Ishiguro Prof. Yu‐Fei Song Prof. Tomoyuki Akutagawa 《Angewandte Chemie (International ed. in English)》2014,53(42):11228-11231
In a mixed‐valence polyoxometalate, electrons are usually delocalized within the cluster anion because of low level of inter‐cluster interaction. Herein, we report the structure and electrical properties of a single crystal in which mixed‐valence polyoxometalates were electrically wired by cationic π‐molecules of tetrathiafulvalene substituted with pyridinium. Electron‐transport characteristics are suggested to represent electron hopping through strong interactions between cluster and cationic π‐molecules. 相似文献
102.
Adil Anwar Hiba Anwar Takeshi Yamauchi Ryan Tseng Rajesh Agarwal Lawrence D Horwitz Zili Zhai Mayumi Fujita 《Photochemistry and photobiology》2020,96(4):870-876
Ultraviolet B (UVB) radiation is known as a culprit in skin carcinogenesis. We have previously reported that bucillamine (N-[2-mercapto-2-methylpropionyl]-L-cysteine), a cysteine derivative with antioxidant and anti-inflammatory capacity, protects against UVB-induced p53 activation and inflammatory responses in mouse skin. Since MAPK signaling pathways regulate p53 expression and activation, here we determined bucillamine effect on UVB-mediated MAPK activation in vitro using human skin keratinocyte cell line HaCaT and in vivo using SKH-1 hairless mouse skin. A single low dose of UVB (30 mJ cm−2) resulted in increased JNK/MAPK phosphorylation and caspase-3 cleavage in HaCaT cells. However, JNK activation and casaspe-3 cleavage were inhibited by pretreatment of HaCaT cells with physiological doses of bucillamine (25 and 100 µm ). Consistent with these results, bucillamine pretreatment in mice (20 mg kg−1) inhibited JNK/MAPK and ERK/MAPK activation in skin epidermal cells at 6–12 and 24 h, respectively, after UVB exposure. Moreover, bucillamine attenuated UVB-induced Ki-67-positive cells and cleaved caspase-3-positive cells in mouse skin. These findings demonstrate that bucillamine inhibits UVB-induced MAPK signaling, cell proliferation and apoptosis. Together with our previous report, we provide evidence that bucillamine has a photoprotective effect against UV exposure. 相似文献
103.
Dr. Soichiro Nakatsuka Yusuke Watanabe Yoshinobu Kamakura Prof. Satoshi Horike Prof. Daisuke Tanaka Prof. Takuji Hatakeyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1451-1455
A triphosphaazatriangulene (H3L) was synthesized through an intramolecular triple phospha-Friedel–Crafts reaction. The H3L triangulene contains three phosphinate groups and an extended π-conjugated framework, which enables the stimuli-responsive reversible transformation of [Cu(HL)(DMSO)⋅(MeOH)]n, a 3D-MOF that exhibits reversible sorption characteristics, into (H3L⋅0.5 [Cu2(OH)4⋅6 H2O] ⋅4 H2O), a 1D-columnar assembled proton-conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10−3 S cm−1 at 95 % relative humidity and 60 °C. 相似文献
104.
Chaohai Wang Dr. Jeonghun Kim Dr. Jing Tang Dr. Jongbeom Na Prof. Yong-Mook Kang Minjun Kim Hyunsoo Lim Prof. Yoshio Bando Prof. Jiansheng Li Prof. Yusuke Yamauchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(5):2082-2086
Carbon aerogels (CAs) with 3D interconnected networks hold promise for application in areas such as pollutant treatment, energy storage, and electrocatalysis. In spite of this, it remains challenging to synthesize high-performance CAs on a large scale in a simple and sustainable manner. We report an eco-friendly method for the scalable synthesis of ultralight and superporous CAs by using cheap and widely available agarose (AG) biomass as the carbon precursor. Zeolitic imidazolate framework-8 (ZIF-8) with high porosity is introduced into the AG aerogels to increase the specific surface area and enable heteroatom doping. After pyrolysis under inert atmosphere, the ZIF-8/AG-derived nitrogen-doped CAs show a highly interconnected porous mazelike structure with a low density of 24 mg cm−3, a high specific surface area of 516 m2 g−1, and a large pore volume of 0.58 cm−3 g−1. The resulting CAs exhibit significant potential for application in the adsorption of organic pollutants. 相似文献
105.
Raku Watanabe Dr. Nobuki Kato Kengo Hayashi Sho Tozawa Dr. Yusuke Ogura Prof. Shigefumi Kuwahara Prof. Minoru Ueda 《ChemistryOpen》2020,9(10):1008-1017
An efficient and stereoselective syntheses of all the possible stereoisomers of coronafacic acid (CFA) has been developed. The stereochemistries of C3a and C7a were controlled in a diastereoselective Diels-Alder type cycloaddition using a chiral auxiliary. CFA and 6-epi-CFA were synthesized by hydrogenation of a common intermediate. During the synthesis of 6-epi-CFA, we established that its cis-fused configuration is important for the introduction of C4-C5 double bond by dehydration. This report is the first practical synthesis of both 6-epi-CFA, and its enantiomer. 相似文献
106.
Yu Hoshino Shohei Taniguchi Hinata Takimoto Sotaro Akashi Sho Katakami Yusuke Yonamine Yoshiko Miura 《Angewandte Chemie (International ed. in English)》2020,59(2):679-683
Abiotic ligands that bind to specific biomolecules have attracted attention as substitutes for biomolecular ligands, such as antibodies and aptamers. Radical polymerization enables the production of robust polymeric ligands from inexpensive functional monomers. However, little has been reported about the production of monodispersed polymeric ligands. Herein, we present homogeneous ligands prepared via radical polymerization that recognize epitope sequences on a target peptide and neutralize the toxicity of the peptide. Taking advantage of controlled radical polymerization and separation, a library of multifunctional oligomers with discrete numbers of functional groups was prepared. Affinity screening revealed that the sequence specificity of the oligomer ligands strongly depended on the number of functional groups. The process reported here will become a general step for the development of abiotic ligands that recognize specific peptide sequences. 相似文献
107.
108.
Taisuke Matsuno Yusuke Nakai Yutaka Maniwa Maki Someya Sota Sato Hiroyuki Isobe 《化学:亚洲杂志》2020,15(2):273-278
In a tight host–guest complex assembled solely by nondirectional van der Waals forces, unique motions of the guest, such as solid‐state inertial rotations, emerge. The regulation of dynamic motions is an important element to be explored for novel functions of such complexes, which may be seemingly difficult to achieve because of the nondirectionality of the assembling forces. A regulated, single‐axis rotation was made possible by choosing an appropriate shape of the guest in the tubular host. Specifically, an ellipsoidal guest was made to stand along a cylinder axis of the host, which consequently resulted in single‐axis rotations of the guest in the solid. The rotational frequency was considerably high for solid‐state rotations but was suppressed to 10 GHz, which was 1/20 of the isotropic rotation of a spherical guest. In‐depth kinetic analyses quantitatively revealed that the entropy cost was a determining factor that regulated the dynamics. 相似文献
109.
110.
Sharvan Kumar Kohshi Yoshida Yusuke Hattori Tomohiro Higashino Hiroshi Imahori Shu Seki 《Chemical science》2022,13(6):1594
The stability of singly or multiply negatively charged π-conjugated organic compounds is greatly influenced by their electronic delocalization. Herein, we report a strategic methodology for isolation of a mysterious compound. The isolated compounds, a pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b′]dipyrrole dianion, were highly stable under ambient conditions due to high delocalization of the negative charge over multiple electron deficient C N groups and pyrene π-scaffolds and allowed purification by column chromatography. To our knowledge, this is the first report on TCNE type reductive condensation of malononitrile involving pyrene di- and tetraone and formation of pyrenopyrrole. All compounds were characterized by spectroscopic methods and X-ray crystallography. A UV-vis spectroscopic study shows an intense low energy absorption band with a large absorption coefficient (ε).An ambient stable pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b′]dipyrrole dianion have been isolated and characterized, showing a low energy intense absorption band with the absorption coefficient reaching 7.1 × 104 dm3 mol−1 cm−1. 相似文献