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91.
Ayuko Tsuruoka Akira Takahashi Daisuke Aoki Hideyuki Otsuka 《Angewandte Chemie (International ed. in English)》2020,59(11):4294-4298
Crosslinked polymers (CLPs) exhibit exceptional mechanical properties as well as good chemical and solvent resistance. However, their reprocessing, recycling, and modification remain difficult. One promising approach to overcome this limitation is to introduce dynamic covalent bonds that enable chain‐exchange reactions and network‐structure rearrangements in identical polymer networks (A–A fusion), resulting in self‐healing and reprocessing properties. Reported here is the fusion of two distinct polymer networks (A–B fusion) by the dynamic behavior of bis(2,2,6,6‐tetramethylpiperidin‐1‐yl)disulfide (BiTEMPS) at the interface between different CLPs. The appearance, swelling behavior, and mechanical properties of the fused samples indicate exchange reactions of the BiTEMPS units and the formation of topological bonds at the interface, commensurate with the generation of a CLP that exhibits tunable properties. 相似文献
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Akio Urushima Daisuke Taura Makoto Tanaka Naomichi Horimoto Junki Tanabe Naoki Ousaka Tadashi Mori Eiji Yashima 《Angewandte Chemie (International ed. in English)》2020,59(19):7478-7486
A novel 2,6‐anthrylene‐linked bis(m‐terphenylcarboxylic acid) strand ( 1 ) self‐associates into a racemic double‐helix. In the presence of chiral mono‐ and diamines, either a right‐ or left‐handed double‐helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face‐selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo‐ (anti or syn) and enantiodifferentiating way to afford the chiral anti‐photodimer with up to 98 % enantiomeric excess when (R)‐phenylethylamine was used as a chiral double‐helix inducer. The resulting optically active anti‐photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines. 相似文献
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Journal of Visualization - To enrich the three-dimensional experimental details of vortex structures in rotating Rayleigh–Bénard convection, we established a technique... 相似文献
97.
Kentaro Yonesato Hiroyasu Ito Daisuke Yokogawa Kazuya Yamaguchi Kosuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(38):16361-16365
Small Agn nanoclusters (n<10) have been emerging as promising materials as sensing, biolabeling, and catalysis because of their unique electronic states and optical properties. However, studying synthesis, structure determination, and exploration of their properties remain major challenges as a result of the low stability of small Ag nanoclusters. Herein, we synthesized an atomically precise face‐centered‐cubic‐type small {Ag7}5+ nanocluster supported by a novel triangular hollow polyoxometalate (POM) framework [Si3W27O96]18?. The cluster showed unique {Ag7}5+‐to‐POM charge transfer bands in both visible and UV light regions. Furthermore, this small {Ag7}5+ nanocluster exhibited an unprecedented ultrastability in solution, despite having exposed Ag sites that can be accessed by small molecules, such as O2, water, and solvents. 相似文献
98.
Symbiodinolide is a polyol macrolide isolated from the marine dinoflagellate Symbiodinium sp. in 2007. The C14-C24 fragment of symbiodinolide possessing the 17R/18R/21R absolute configuration, which was obtained as one of the degraded products of symbiodinolide, was synthesized stereoselectively from cis-2-butene-1,4-diol. The detailed comparison of the synthetic product with the degraded product in the spectroscopic data confirmed that the stereostructure of the C14-C24 fragment was 17R, 18R, and 21R. 相似文献
99.
Chunguang HanYoshi Yamano Fumitoshi KakiuchiKazuhiko Nakamura Daisuke Uemura 《Tetrahedron》2011,67(49):9622-9626
An oxidative cleavage of allyl vic-diols to aldehydes catalyzed by a Grubbs carbene complex using a co-oxidant has been established for the first time, with good yields. The utility of this selective cleavage reaction was demonstrated through the use of two huge marine molecules, symbiodinolide and N-p-BrBz palytoxin. 相似文献