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981.
Kouhei Watanabe Ayano Taniguchi Daiki Kaji Nobuyuki Hara Tomomasa Hosoya Aoba Kanesaka Takunori Harada Hiroyuki Nishikawa Yoshitane Imai 《Tetrahedron》2019,75(21):2944-2948
Organic fluorescent molecules are gaining importance because of their potential applications in many devices. Optically active N,N′-bis((1R)-1-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-1-BNP] and N,N′-bis((1R)-2-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-2-BNP] and their antipode, [(S,S)-1-BNP and (S,S)-2-BNP], emit aggregation-induced enhanced (AIEnh) circularly polarized luminescence (CPL) on both a solid organic polymer film (poly(methyl methacrylate)) and solid inorganic KBr pellet. An opposite chirality is essential for generating CPL of inverted sign. However, a pair of enantiomeric organic molecules may not always be easy to prepare. Interestingly, the chiral perylene fluorophores synthesized in this study can emit both positive and negative AIEnh-CPL in the solid state, depending on their position on the naphthylene groups. In addition, no CPL was observed in these compounds from their dilute solutions. 相似文献
982.
983.
Shibata Nori Watanabe Kimitaka Ohashi Masaharu Maruyama Ryo Kuwaki Nobuo Aikawa Kazuhiko 《Optical Review》2019,26(6):644-651
Optical Review - A two-beam interferometer (TBI) with a two-mode fiber (TMF) as a dispersive medium in one arm and air in the other provides evidence of interference related to the complex degree... 相似文献
984.
Mithun Kumar Debnath Wako Oyama Yuya Ono Takuya Sugimoto Rina Watanabe Naoki Haraguchi 《Journal of polymer science. Part A, Polymer chemistry》2021,59(11):1072-1083
Polymer microsphere-supported chiral pyrrolidine catalysts were successfully synthesized by a precipitation polymerization incorporating a methacrylate monomer bearing chiral N-Boc-pyrrolidine moiety, followed by removal of the N-Boc groups. The resulting polymeric catalysts were applied to the asymmetric Michael addition reactions of aldehydes with alkyl vinyl ketones. The effects of the comonomer, the molar ratios within the catalyst, the catalyst loading, the temperature, and the solvent on the catalytic performance were investigated in detail. The reactions were found to proceed smoothly in the absence of a solvent. A hydrophobic polystyrene-based chiral pyrrolidine catalyst exhibited high reactivity (up to 97% yield) and enantioselectivity (up to 95% ee) during these reactions. The catalyst could also be recovered and reused up to five times without significant loss of activity. 相似文献
985.
986.
Mitsuhiro Hirata Takeshi Watanabe Bungo Ochiai Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2012,50(16):3259-3268
Graft terpolymers bearing polyether side chains and poly(methacrylate) stems were synthesized by the graft‐onto reaction of monoamino‐terminated poly(PO9‐co‐EO1) to poly{[5‐(methacryloyloxy)methyl‐1,3‐oxathiolane‐2‐thione]‐co‐n‐butyl methacrylate} [poly(DTCMMA‐co‐BuMA)]. The grafting reaction proceeded via the nucleophilic addition of the terminal amino groups to the five‐membered cyclic dithiocarbonate moieties giving thiol moieties, although the grafting efficiency was low (9–34%) due to the steric hindrance of the side chains. The Tg values of the poly{[DTCMMA‐graft‐poly(PO9‐co‐EO1)]‐co‐BuMA} ranged 27–47 °C, depending on the amounts of flexible poly(PO9‐co‐EO1) chains introduced lowering the Tg values. Poly{[DTCMMA‐graft‐poly(PO9‐co‐EO1)]‐co‐BuMA}s bearing thiol groups were applied for the modification of wool via the disulfide exchange reaction. The modified wool had better dye ability toward a pigment from safflower than the original wool owing to the hydrophilic nature of poly{[DTCMMA‐graft‐poly(PO9‐co‐EO1)]‐co‐BuMA} introduced. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
987.
988.
R. Seki M. Watanabe K. Kurihara 《Journal of Radioanalytical and Nuclear Chemistry》2000,243(2):383-386
The amount of long-lived radioiodine, 129I (half-life 1.57·107 y) in the Japanese environment has been studied by measuring thyroids of humans and animals. The collected samples were thyroids of (1) humans in Ibaraki Prefecture, in Kanto district, the central part of Japan, (2) cattle in Aomori Prefecture, north part of Japan, and (3) wild deer in Chiba Prefecture, in Kanto district. The measured mean isotopic ratio 129I/127I for thyroids of cattle in Aomori Prefecture is 3.5±1.8·10-9. A higher value of 14±5·10-9 has been obtained for thyroids of wild deer in Kanto district. On the other hand, the measured ratio for human thyroids in Kanto district is 1±0.2·10-9. This value is significantly lower than that of cattle thyroids in Aomori and also those reported for human thyroids in Europe and USA. The higher mean ratio for cattle thyroid in Kanto district is possibly explained by the influence of nuclear reprocessing plant. Lower mean ratio for human thyroid might be due to higher dietary intake of algae. 相似文献
989.
P. Christopher Selvin S. Watanabe J. S. Ayala-Arenas 《Radiation Physics and Chemistry》2001,61(3-6):531-533
The natural mineral chrysocolla (CuSiO3·2H2O) has been investigated in terms of thermally stimulated luminescence and EPR measurements. The glow curves for natural samples present three glow peaks at 190, 357 and 450°C. Pre annealed and subsequently irradiated samples give rise to four glow peaks at 140°C, 193°C, 305°C and 450°C. The formation of Ho centers at the expense of water molecules present in the channels has been identified by EPR measurements. 相似文献
990.
Hiroshi Watanabe Tomohiro Sato Kunihiro Osaki Mutsuo Matsumoto Dobrin P. Bossev Cathy E. McNamee Masaru Nakahara 《Rheologica Acta》2000,39(2):110-121
Linear viscoelastic behavior was investigated for aqueous solutions of perfluorooctyl sulfonate (C8F17SO−
3; abbreviated as FOS) micelles having a mixture of tetraethylammonium (N+(C2H5)4; TEA) and lithium (Li+) ions as the counter-ions. The solutions had the same FOS concentration (0.1 mol l−1) and various Li+ fractions in the counter-ions, φLi = 0−0.6, and the FOS micelles in these solutions formed threads which further organized into dendritic networks. At T ≤ 15 °C,
the terminal relaxation time τ and the viscosity η, governed by thermal scission of the networks, increased with increasing
φLi up to 0.55. A further increase of φLi resulted in decreases of τ and η and in broadening of the relaxation mode distribution. These rheological changes are discussed
in relation to the role of TEA ions in thermal scission: Previous NMR studies revealed that only a fraction of TEA ions were
tightly bound to the FOS micellar surfaces and these bound ions stabilized the thread/network structures. The concentration
of non-bound TEA ions, CTEA
*, decreased and finally vanished on increasing φLi up to φLi
* ≅ 0.6, and the concentration of the bound TEA ions significantly decreased on a further increase of φLi. The non-bound TEA ions appeared to catalyze the thermal scission of the FOS threads, and the observed increases of τ and
η for φLi < 0.55 were attributed to the decrease of CTEA
*. On the other hand, the decreases of τ and η as well as the broadening of the mode distribution, found for φLi > 0.55 (where CTEA
* ≅ 0), were related to destabilization of the FOS threads/networks due to a shortage of the bound TEA ions and to the existence
of concentrated Li+ ions. Viscoelastic data of pure FOSTEA and FOSTEA/FOSLi/TEACl solutions lent support to these arguments for the role of TEA
ions in the relaxation of FOSTEA/FOSLi solutions.
Received: 12 October 1999/Accepted: 1 November 1999 相似文献