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981.
Ryosuke Takahashi 《Mathematische Zeitschrift》2015,281(3-4):1021-1034
982.
Synthetic Control of the Excited‐State Dynamics and Circularly Polarized Luminescence of Fluorescent “Push–Pull” Tetrathia[9]helicenes 下载免费PDF全文
Yuki Yamamoto Dr. Hayato Sakai Dr. Junpei Yuasa Prof. Yasuyuki Araki Prof. Takehiko Wada Prof. Tomo Sakanoue Prof. Taishi Takenobu Prof. Tsuyoshi Kawai Prof. Taku Hasobe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4263-4273
A series of fluorescent “push‐pull” tetrathia[9]helicenes based on quinoxaline (acceptor) fused with tetrathia[9]helicene (donor) derivatives was synthesized for control of the excited‐state dynamics and circularly polarized luminescence (CPL) properties. In this work, introduction of a quinoxaline onto the tetrathia[9]helicene skeleton induced the “push–pull” character, which was enhanced by further introduction of an electron‐releasing Me2N group or an electron‐withdrawing NC group onto the quinoxaline unit (denoted as Me2N‐QTTH and NC‐QTTH, respectively). These trends were successfully discussed in terms of by electrochemical measurements and density functional theory (DFT) calculations. As a consequence, significant enhancements in the fluorescence quantum yields (ΦFL) were achieved. In particular, the maximum ΦFL of Me2N‐QTTH was 0.43 in benzene (NC‐QTTH: ΦFL=0.30), which is more than 20 times larger than that of a pristine tetrathia[9]helicene (denoted as TTH; ΦFL=0.02). These enhancements were also explained by kinetic discussion of the excited‐state dynamics such as fluorescence and intersystem crossing (ISC) pathways. Such significant enhancements of the ΦFL values thus enabled us to show the excellent CPL properties. The value of anisotropy factor gCPL (normalized difference in emission of right‐handed and left‐handed circularly polarized light) was estimated to be 3.0×10?3 for NC‐QTTH. 相似文献
983.
Hiroki Mori Ryosuke Takahashi Yasushi Nishihara 《Journal of polymer science. Part A, Polymer chemistry》2018,56(23):2646-2655
A phenanthrodithiophene (PDT)-difluorobenzoxadiazole (DFBO) copolymer, P-PDT-DFBO , was synthesized and characterized. Replacing a thiadiazole with an oxadiazole ring gives the synthesized polymer a highest occupied molecular orbital (HOMO) about 0.1 V lower, and lowest unoccupied molecular orbital energy levels lower than those of its benzothiadiazole (BT) counterpart, due to the more electron-deficient oxadiazole. Furthermore, since oxadiazole has a larger dipole moment than BT, P-PDT-DFBO exhibits greater aggregation strength than previously reported for P-PDT-DFBT . The low-lying HOMO level of P-PDT-DFBO gave about 0.1 V higher open-circuit voltage (Voc), yielding over 0.9 V in a fabricated solar cell. From grazing incidence wide-angle X-ray diffraction analysis, P-PDT-DFBO formed a favorable face-on orientation in both neat and blended films, indicating that the incorporation of an oxadiazole moiety can enhance Voc without any orientation change in the solid state. However, a P-PDT-DFBO -based cell exhibited significantly lower Jsc and FF, and thus less power conversion efficiency, not >4.43%, due to its lower hole mobility than P-PDT-DFBT . One possible reason for poor performance may be the low crystallinity of P-PDT-DFBO in blended film. This may be caused by its strong aggregation tendency, leading to fast crystallization into a semiamorphous structure or to interference with the construction of long-range ordered structure. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2646–2655 相似文献
984.
Journal of Inclusion Phenomena and Macrocyclic Chemistry - Biological systems display a range of sophisticated functions that cannot be performed by artificial systems, through intricate... 相似文献
985.
986.
Okamoto Ryosuke Hayashi Kazuhide Matsumoto Satoshi Suzuki Naomi Terauchi Masami 《Journal of Solid State Electrochemistry》2017,21(11):3301-3314
Journal of Solid State Electrochemistry - It has been reported that the partial substitution of Fe for Ni in LiMn1.5Ni0.5O4 improves the rate capability of batteries wherein it is used as a cathode... 相似文献
987.
Osamu Sakai Yu Hiraoka Naoya Kihara Ella Blanquet Keiichiro Urabe Masanobu Tanaka 《Plasma Chemistry and Plasma Processing》2016,36(1):281-294
Microdischarge-induced reaction processes working at atmospheric pressure create fractal-like network structure of metal nano-particles which shows variable electric and optical properties. Due to their smallness, microdischarges or microplasmas can be installed in a gas-tubing system, and they enable us to create a compact chemical reduction reactor which includes decomposers of molecules, gas flows, and aqueous solutions with metallic ions at atmospheric pressure. Ammonia (NH3) gas is successfully decomposed in this reactor, and its products which include mainly hydrazine (N2H4) and flow in the downstream induce reduction reactions for AgNO3 solution. Various parameters in the reactor trigger formation of functional patterns of silver nano-particles like partially transparent layers whose conductivity is variable. Optical properties of this equivalent films show some absorption spectra coming from structure resonances, which can be an optical metamaterials in this self-assembly process. 相似文献
988.
Polystyrene with pendant Ni-(II)-4,4′, 4, 4 -tetracarboxyphthalocyanine (NiPctc) was synthesized by reacting NiPctc with partially chloromethylated polystyrene. Photoreduction of methylviologen by visible light was accomplished with the modified polymer. The photocatalytic activity was enhanced by bonding the NiPctc units to the polymer. The relationship between the catalytic activity and the structure of the modified polymer is discussed. 相似文献
989.
Tomohiro Hirano Takahiro Kamikubo Yuya Okumura Yoichi Bando Ryosuke Yamaoka Takeshi Mori Koichi Ute 《Journal of polymer science. Part A, Polymer chemistry》2009,47(10):2539-2550
Radical polymerization of N‐isopropylacrylamide (NIPAAm) in toluene at low temperatures, in the presence of fluorinated‐alcohols, produced heterotactic polymer comprising an alternating sequence of meso and racemo dyads. The heterotacticity reached 70% in triads when polymerization was carried out at ?40 °C using nonafluoro‐tert‐butanol as the added alcohol. NMR analysis revealed that formation of a 1:1 complex of NIPAAm and fluorinated‐alcohol through C?O···H? O hydrogen bonding induces the heterotactic specificity. A mechanism for the heterotactic‐specific polymerization is proposed. Examination of the phase transition behavior of aqueous solutions of heterotactic poly(NIPAAm) revealed that the hysteresis of the phase transition between the heating and cooling cycles depended on the average length of meso dyads in poly(NIPAAm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2539–2550, 2009 相似文献
990.
A data compression method based on image encoding techniques is presented for a flow simulation data set. An input flow field data set is converted into the octree structure by discrete wavelet transform, and then quantized finely or coarsely depending on its importance in the flow field. Embedded zerotree wavelet encoding as the image encoding technique and entropy encoding reduce the data size by making use of the octree structure created previously. The present compression method is incorporated in a block‐structured Cartesian mesh method called Building‐Cube method. The Building‐Cube method gives not only good performance in the flow simulation but also consistency with the embedded zerotree wavelet encoding in the data compression. Three compression cases for incompressible and compressible flow simulations, including a large‐scale simulation with O(10 8) mesh points, demonstrate that the present compression method gives both high compression ratios and good qualities of compressed data. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献