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101.
Prof. Joe Otsuki Takumi Okumura Dr. Kosuke Sugawa Dr. Shin-ichiro Kawano Prof. Kentaro Tanaka Dr. Takehiro Hirao Prof. Takeharu Haino Yu Jin Lee Seongsoo Kang Prof. Dongho Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4053-4063
Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct 1H NMR spectrum in CDCl3, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the 1H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs. 相似文献
102.
The title pyridinium salts and pyridinium ylide-platinum(II) complexes have been reduced through a one-electron process at more positive potentials by 0.3 0.6 V than the corresponding ylides. Both the reduced pyridinium salts and Pt(II)-ylide complexes reacted with dioxygen, followed by elimination of the N-methylene and ylide protons to form pyridinium ylides and Pt(II)-pyridinium ylide complexes containing the three-coordinate ylide carbon atom, respectively. 相似文献
103.
By using an optical system simulator, we investigated the tunable delay-line with an optical SSB modulator and an optical fiber loop, where the delay can be controlled by the electric signal fed to the modulator. 相似文献
104.
Dr. Kosuke Ono Shunsuke Shimo Dr. Kohei Takahashi Dr. Nobuhiro Yasuda Dr. Hidehiro Uekusa Prof. Nobuharu Iwasawa 《Angewandte Chemie (International ed. in English)》2018,57(12):3113-3117
Dynamic interconversion between large covalent organic cages was achieved simply by heating or acid/base treatment. A mixture of the boroxine cages 12‐mer and 15‐mer was cleanly converted into a pyridine adduct of the 9‐mer boroxine cage upon treatment with pyridine, and the geometry of N‐coordinated boron atoms changed from trigonal to tetrahedral. The reverse reaction was achieved by heating or acid treatment. In this process, the larger boroxine cages 12‐mer and 15‐mer were found to be entropically favored owing to the release of free pyridine molecules from 9‐mer ?6 Py. 相似文献
105.
Utilization of Donor–Acceptor Interactions for the Catalytic Acceleration of Nucleophilic Additions to Aromatic Carbonyl Compounds
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Tatsuhiro Uchikura Dr. Kosuke Ono Dr. Kohei Takahashi Prof. Nobuharu Iwasawa 《Angewandte Chemie (International ed. in English)》2018,57(8):2130-2133
A conceptually new method for the catalytic electrophilic activation of aromatic carbonyl substrates, by utilizing donor–acceptor interactions between an electron‐deficient macrocyclic boronic ester host ( [2+2] BTH‐F ) and an aromatic carbonyl guest substrate, was realized. In the presence of a catalytic amount of [2+2] BTH‐F , dramatic acceleration of the nucleophilic addition of a ketene silyl acetal towards either electron‐rich aromatic aldehydes or ketones was achieved. Several control experiments confirmed that inclusion of the aromatic substrates within [2+2] BTH‐F , through efficient donor–acceptor interactions, is essential for the acceleration of the reaction. 相似文献
106.
The stability of beta-galactosidase dosage forms was studied by differential scanning calorimetry (DSC). It was found that the observed enthalpy of thermal denaturation was approximately in proportion to remaining enzyme activity, and denaturation temperature was related to protein stability. These results suggest that DSC can be used to determine native proteins in dosage forms and to clarify the factors affecting protein stability. The DSC method seems to be more convenient than conventional activity assay methods, and useful to follow protein denaturation during the manufacturing process and storage of dosage forms. 相似文献
107.
The applicability of 0.05 mol kg(-1) potassium hydrogen phthalate (KHPh(S), S=the solvent under study) as reference value pH standard (RVS) was studied in water-organic solvent mixtures. Phthalic acid in various aqueous organic solvent mixtures was titrated potentiometrically with Bu(4)NOH (MeOH), using a pH-ISFET and a glass electrode as pH-sensors, and the buffer capacity of the HPh(-) solution was roughly estimated from the difference between the first and second half-neutralization potentials. The influence of potassium ion to the buffer capacity was also studied, titrating KHPh and Et(4)NHPh with CF(3)SO(3)H and Bu(4)NOH (MeOH) and comparing the titration curves. The KHPh solution loses its buffer capacity if the solvent mixture has an aprotic property. For aqueous mixtures of protophilic aprotic solvents (e.g. DMSO and DMF), it is unsuitable as RVS if the water content is less than ca. 40 (v/v)%. The necessity of selecting subsidiary pH standard(s) is suggested for the solvent systems in which KHPh is inapplicable. 相似文献
108.
109.
Ryosuke NAKANISHI Kosuke TAKEUCHI Kazunori AKIZUKI Ryoma NAKAGOSHI Hironobu KAKIHANA 《Physical Therapy Research》2020,23(2):195
Objective: Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase. Methods: Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES. Results: 20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES. Conclusion: These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity. 相似文献
110.