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991.
Bridged Stilbenes: AIEgens Designed via a Simple Strategy to Control the Non‐radiative Decay Pathway
Riki Iwai Satoshi Suzuki Shunsuke Sasaki Amir Sharidan Sairi Kazunobu Igawa Tomoyoshi Suenobu Keiji Morokuma Gen‐ichi Konishi 《Angewandte Chemie (International ed. in English)》2020,59(26):10566-10573
To broaden the application of aggregation‐induced emission (AIE) luminogens (AIEgens), the design of novel small‐molecular dyes that exhibit high fluorescence quantum yield (Φfl) in the solid state is required. Considering that the mechanism of AIE can be rationalized based on steric avoidance of non‐radiative decay pathways, a series of bridged stilbenes was designed, and their non‐radiative decay pathways were investigated theoretically. Bridged stilbenes with short alkyl chains exhibited a strong fluorescence emission in solution and in the solid state, while bridged stilbenes with long alkyl chains exhibited AIE. Based on this theoretical prediction, we developed the bridged stilbenes BPST[7] and DPB[7], which demonstrate excellent AIE behavior. 相似文献
992.
Hideyuki Nakanishi Yuto Kawabata Shogo Tsujiai Hayato Tanaka Satoshi Teraji Gbor Holl Istvn Lagzi Tomohisa Norisuye Qui Tran‐Cong‐Miyata 《Angewandte Chemie (International ed. in English)》2020,59(31):13086-13092
The development of methods to pattern nanocrystals with different sizes and shapes remains a challenge. In this study, we demonstrate a unique class of bottom‐up approaches to assemble nanocrystals into patterns. Our approach for patterning nanocrystals focuses on the utilization and control of the chemical reaction of solvents surrounding nanocrystals. The photopolymerization of solvent molecules through a photomask creates time‐dependent concentration gradients of the solvents. Dispersed nanocrystals such as silver nanowires (AgNWs) migrate and are gradually organized and integrated into the polymerizing films based on the concentration gradients. The AgNW‐embedded film properties are determined by the organized AgNW structures and include light transmission and electrical conductivity. Overall, the demonstrated method is very simple, widely applicable to various nanocrystals and solvents, and can thus contribute to the development of a new class of nanocrystal patterning methods. 相似文献
993.
Rika Okuma Tomoki Kuwahara Takafumi Yoshikane Mizuki Watanabe Patricia Dranchak James Inglese Satoshi Shuto Yuki Goto Hiroaki Suga 《化学:亚洲杂志》2020,15(17):2631-2636
Here we report the construction of an mRNA‐encoded library of thioether‐closed macrocyclic peptides by using an N‐chloroacetyl‐cyclopropane‐containing exotic initiator whose structure is more constrained than the ordinary N‐chloroacetyl‐α‐amino acid initiators. The use of such an initiator has led to a macrocycle library with significantly suppressed population of lariat‐shaped species compared with the conventional libraries. We previously used a conventional library and identified a small lariat thioether‐macrocycle with a tail peptide with a C‐terminal free Cys whose sidechain plays an essential role in potent inhibitory activity against a parasitic model enzyme, phosphoglycerate mutase. On the other hand, the cyclopropane‐containing macrocycle library has yielded a larger thioether‐macrocycle lacking a free Cys residue, which exhibits potent inhibitory activity to the same enzyme with a different mode of action. This result indicates that such a cyclopropane‐containing macrocycle library would allow us to access mechanistically distinct macrocycles. 相似文献
994.
Akimitsu Ishihara Satoshi Tominaka Shigenori Mitsushima Hideto Imai Osamu Sugino Ken-ichiro Ota 《Current Opinion in Electrochemistry》2020
To obtain an ideal electrocatalysts for hydrogen fuel cells, we investigated group 4 and 5 oxide-based compounds because of their high degree of freedom. First-principles calculations revealed that oxide surfaces such as those of titanium oxide could break down the universal scaling to achieve the ideal state of the oxygen reduction reaction. We experimentally clarified that the active sites were oxygen vacancies for tantalum and zirconium oxides, in addition to doped foreign elements and crystalline structures for titanium oxide. We successfully demonstrated that precious metal-free and carbon-free oxide-based cathodes have high quality active sites and superior durability in 0.1 M sulfuric acid at 80°C. Our strategy was developed as follows: (1) Active sites are created on the oxide surface by modifying the crystalline structure and electronic states and (2) electrons participating in the oxygen reduction reaction are supplied by nanosized oxide particles and oxide films through the tunneling effect of electrons. 相似文献
995.
Ahsan Habib Satoshi Ninomiya Lee Chuin Chen Dilshadbek T. Usmanov Kenzo Hiraoka 《Journal of the American Society for Mass Spectrometry》2014,25(7):1177-1180
In this work, desorption of nonvolatile analytes induced by friction was studied. The nonvolatile compounds deposited on the perfluoroalkoxy substrate were gently touched by an ultrasonic cutter oscillating with a frequency of 40 kHz. The desorbed molecules were ionized by a dielectric barrier discharge (DBD) ion source. Efficient desorption of samples such as drugs, pharmaceuticals, amino acids, and explosives was observed. The limits of detection for these compounds were about 1 ng. Many compounds were detected in their protonated forms without undergoing significant fragmentation. When the DBD was off, no ions for the neutral samples could be detected, meaning that only desorption along with little ionization took place by the present technique. Figure
? 相似文献
996.
Superconducting Double Perovskite Bismuth Oxide Prepared by a Low‐Temperature Hydrothermal Reaction 下载免费PDF全文
Mirza H. K. Rubel Prof. Akira Miura Prof. Takahiro Takei Prof. Nobuhiro Kumada M. Mozahar Ali Prof. Masanori Nagao Prof. Satoshi Watauchi Prof. Isao Tanaka Prof. Kengo Oka Prof. Masaki Azuma Prof. Eisuke Magome Prof. Chikako Moriyoshi Prof. Yoshihiro Kuroiwa Prof. A. K. M. Azharul Islam 《Angewandte Chemie (International ed. in English)》2014,53(14):3599-3603
Perovskite‐type structures (ABO3) have received significant attention because of their crystallographic aspects and physical properties, but there has been no clear evidence of a superconductor with a double‐perovskite‐type structure, whose different elements occupy A and/or B sites in ordered ways. In this report, hydrothermal synthesis at 220 °C produced a new superconductor with an A‐site‐ordered double perovskite structure, (Na0.25K0.45)(Ba1.00)3(Bi1.00)4O12, with a maximum Tc of about 27 K. 相似文献
997.
2,6‐Diphospha‐s‐indacene‐1,3,5,7(2 H,6 H)‐tetraone: A Phosphorus Analogue of Aromatic Diimides with the Minimal Core Exhibiting High Electron‐Accepting Ability 下载免费PDF全文
Dr. Youhei Takeda Takuya Nishida Prof. Dr. Satoshi Minakata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10266-10270
Phosphorus analogues of pyrromellitic diimides (PyDIs), which represent a family of privileged electron‐accepting organic compounds, have been successfully synthesized as novel electron‐accepting π‐conjugated molecules. Investigation into their physicochemical properties uncovered their prominent electron‐accepting abilities over the corresponding PyDI. Furthermore, theoretical studies revealed the significant contribution of σ*–π* hyperconjugation in stabilizing the LUMO+1. 相似文献
998.
Universal Reaction Mechanism of Boronic Acids with Diols in Aqueous Solution: Kinetics and the Basic Concept of a Conditional Formation Constant 下载免费PDF全文
Yuki Furikado Tomomi Nagahata Takuya Okamoto Dr. Tomoaki Sugaya Prof. Dr. Satoshi Iwatsuki Prof. Dr. Masahiko Inamo Prof. Dr. Hideo D. Takagi Prof. Dr. Akira Odani Prof. Dr. Koji Ishihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13194-13202
To establish a detailed reaction mechanism for the condensation between a boronic acid, RB(OH)2, and a diol, H2L, in aqueous solution, the acid dissociation constants (${K{{{\rm BL}\hfill \atop {\rm a}\hfill}}}$ ) of boronic acid diol esters (HBLs) were determined based on the well‐established concept of conditional formation constants of metal complexes. The pKa values of HBLs were 2.30, 2.77, and 2.00 for the reaction systems, 2,4‐difluorophenylboronic acid and chromotropic acid, 3‐nitrophenylboronic acid and alizarin red S, and phenylboronic acid and alizarin red S, respectively. A general and precise reaction mechanism of RB(OH)2 with H2L in aqueous solution, which can serve as a universal reaction mechanism for RB(OH)2 and H2L, was proposed on the basis of (a) the relative kinetic reactivities of the RB(OH)2 and its conjugate base, that is, the boronate ion, toward H2L, and (b) the determined pKa values of HBLs. The use of the conditional formation constant, K′, based on the main reaction: RB(OH)2+H2L ${{\mathop \leftrightarrow \limits ^{K{_{1}}}_{}}}$ RB(L)(OH)?+H3O+ instead of the binding constant has been proposed for the general reaction of uncomplexed boronic acid species (B′) with uncomplexed diol species (L′) to form boronic acid diol complex species (esters, BL′) in aqueous solution at pH 5–11: B′+L′ ${{\mathop \leftrightarrow \limits ^{K{^\prime}}_{}}}$ BL′. The proposed reaction mechanism explains perfectly the formation of boronic acid diol ester in aqueous solution. 相似文献
999.
The jamaicamides, isolated in Jamaica from the cyanobacterium Lyngbya majuscula, are new mixed polyketide-peptides that are known to be sodium channel blockers. The polyketide moiety contains an (E)-vinyl chloride, an undetermined methyl stereocenter (C9), and an (E)-olefin. Herein, we report the synthesis of the (E)-olefin moiety of the polyketide of the jamaicamides utilizing a Kocienski–Julia coupling. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
1000.
Kiyoshi Kobayashi Masateru Nishioka Koichi Sato Tomoya Inoue Satoshi Hamakawa Tatsuo Tsunoda 《Journal of Solid State Electrochemistry》2006,10(8):629-634
An oxygen-permeable composite constituted to oxide ionic conductor phase (Ce0.75Nd0.25O1.875) and oxide electronic conductor phase (Nd1.8Ce0.2CuO4) was prepared using the acetate pyrolysis method. Based on electrical conductivity measurements, total electrical conductivity
of 75 mol% Ce0.75Nd0.25O1.875–25 mol% Nd1.8Ce0.2CuO4 composite material was governed by the electronic conduction paths. With respect to the oxygen permeation properties, the
results showed that oxygen permeation properties were unexplainable by a simple composite rule using the electrical transport
properties of the bulk Ce0.75Nd0.25O1.875 and the bulk Nd1.8Ce0.2CuO4. 相似文献