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11.
Shohei Inoue 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):651-664
Carbon dioxide and epoxide copolymerize in the presence of some organometallic catalyst systems under moderate conditions to give aliphatic polycarbonates of high molecular weight. Some metalloporphyrins of aluminum and zinc were found to act as novel catalysts for the polymerization of epoxide and for the copolymerization of carbon dioxide and epoxide, though not alternating. The polymers are characterized by the narrow molecular weight distribution and the unusual stereoregularity. Starting from the copolymerization of carbon dioxide and trimethylsilyl glycidyl ether with diethylzinc-water catalyst system, a readily degradable polycarbonate having hydroxyl group was obtained. 相似文献
12.
Shohei Inoue 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5-7):571-582
Aluminum porphyrin is an excellent initiator for the living polymerizations of a wide variety of monomers such as epoxide, β-lactone, δ-lactone, ε-lactone, and lactide, and also for the alternating copolymerization of epoxide and cyclic acid anhydride or carbon dioxide, to give polymers and copolymers with narrow molecular weight distribution. Aluminum porphyrin was recently found to initiate also the living polymerization of methacrylic ester. In the polymerizations of epoxides and lactones initiated with aluminum porphyrin in the presence of an appropriate protic compound, polymers with narrow molecular weight can be obtained with the number of the polymer molecules more than those of the initiator. This fact demonstrates the “immortal” nature of the polymerization due to unusual reactivities of aluminum prophyrin. 相似文献
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Shotaro Hayashi Fumitaka Ishiwari Takanori Fukushima Shohei Mikage Yutaka Imamura Motomichi Tashiro Michio Katouda 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16329-16335
Elastic organic crystals have attracted considerable attention as next-generation flexible smart materials. However, the detailed information on both molecular packing change and macroscopic mechanical crystal deformations upon applied stress is still insufficient. Herein, we report that fluorescent single crystals of 9,10-dibromoanthracene are elastically bendable and stretchable, which allows a detailed investigation of the deformation behavior. We clearly observed a Poisson effect for the crystal, where the short axes (b and c-axes) of the crystal are contracted upon elongation along the long axis (a-axis). Moreover, we found that the Poisson's ratios along the b-axis and c-axis are largely different. Theoretical molecular simulation suggests that the tilting motion of the anthracene may be responsible for the large deformation along the c-axis. Spatially resolved photoluminescence (PL) measurement of the bent elastic crystals reveals that the PL spectra at the outer (elongated), central (neutral), and inner (contracted) sides are different from each other. 相似文献
17.
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
18.
Ryo Kimura Hikaru Kuramochi Pengpeng Liu Takuya Yamakado Atsuhiro Osuka Tahei Tahara Shohei Saito 《Angewandte Chemie (International ed. in English)》2020,59(38):16430-16435
Flapping fluorophores (FLAP) with a flexible 8π ring are rapidly gaining attention as a versatile photofunctional system. Here we report a highly photostable “flapping peryleneimide” with an unprecedented fluorogenic mechanism based on a bent‐to‐planar conformational change in the S1 excited state. The S1 planarization induces an electronic configurational switch, almost quenching the inherent fluorescence (FL) of the peryleneimide moieties. However, the FL quantum yield is remarkably improved with a prolonged lifetime upon a slight environmental change. This fluorogenic function is realized by sensitive π‐conjugation design, as a more π‐expanded analogue does not show the planarization dynamics. With strong visible‐light absorption, the FL lifetime response synchronized with the flexible flapping motion is useful for the latest optical techniques such as FL lifetime imaging microscopy (FLIM). 相似文献
19.
Shotaro Hayashi Fumitaka Ishiwari Takanori Fukushima Shohei Mikage Yutaka Imamura Motomichi Tashiro Michio Katouda 《Angewandte Chemie (International ed. in English)》2020,59(37):16195-16201
Elastic organic crystals have attracted considerable attention as next‐generation flexible smart materials. However, the detailed information on both molecular packing change and macroscopic mechanical crystal deformations upon applied stress is still insufficient. Herein, we report that fluorescent single crystals of 9,10‐dibromoanthracene are elastically bendable and stretchable, which allows a detailed investigation of the deformation behavior. We clearly observed a Poisson effect for the crystal, where the short axes (b and c‐axes) of the crystal are contracted upon elongation along the long axis (a‐axis). Moreover, we found that the Poisson's ratios along the b‐axis and c‐axis are largely different. Theoretical molecular simulation suggests that the tilting motion of the anthracene may be responsible for the large deformation along the c‐axis. Spatially resolved photoluminescence (PL) measurement of the bent elastic crystals reveals that the PL spectra at the outer (elongated), central (neutral), and inner (contracted) sides are different from each other. 相似文献
20.
Yuji Kikukawa Kensuke Seto Daiki Watanabe Hiromasa Kitajima Misaki Katayama Shohei Yamashita Yasuhiro Inada Yoshihito Hayashi 《Angewandte Chemie (International ed. in English)》2020,59(34):14399-14403
Dodecavanadate, [V12O32]4? (V12), possesses a 4.4 Å cavity entrance, and the cavity shows unique electrophilicity. Owing to the high polarizability, Br2 was inserted into V12, inducing the inversion of one of the VO5 square pyramids to form [V12O32(Br2)]4? (V12(Br2)). The inserted Br2 molecule was polarized and showed a peak at 185 cm?1 in the IR spectrum. The reaction of V12(Br2) and toluene yielded bromination of toluene at the ring, showing the electrophilicity of the inserted Br2 molecule. Compound V12(Br2) also reacted with propane, n‐butane, and n‐pentane to give brominated alkanes. Bromination with V12(Br2) showed high selectivity for 3‐bromopentane (64 %) among the monobromopentane products and preferred threo isomer among 2‐,3‐dibromobutane and 2,3‐dibromopenane. The unique inorganic cavity traps Br2 leading the polarization of the diatomic molecule. Owing to its new reaction field, the trapped Br2 shows selective functionalization of alkanes. 相似文献