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111.
112.
Silacyclophanes possessing two disilanyl pillars were synthesized from tricyclic heteroarenes in one‐pot synthetic procedures. The step‐like anti structures of three congeners bearing two heteroarene units were revealed in single crystals by X‐ray crystallographic analysis. Depending on the structures of aromatic units, torsion angles at the disilanyl pillars altered to maintain the overall step‐like molecular structures. The structure, however, fluctuated between anti and syn conformers in a solution phase despite the presence of eight methyl groups on the ring periphery. The analysis of the coalescence temperature with NMR spectroscopy showed the fundamental energetics of the dynamics. The subtle structural differences affected the dynamic behavior of the silacyclophanes. 相似文献
113.
Invited for this month''s cover picture is the group of Dr. Satoko Hayashi at Faculty of Systems Engineering and Chemistry at Wakayama University. The cover picture shows the linear Se16 σ(16c–30e) interactions, illustrated by the molecular graph type on the optimized structure of the dicationic octamer of 1,5‐(diselena)cane. HOMO‐1 of ψ462 is drawn on the structure, which is located predominantly on the Se atoms. The optimized structure is stable, due to the nice engagement between the (CH2)3 moieties. The contour maps of ρ(r) are also drawn on the molecular C s planes of the dicationic dimer and trimer to demonstrate clearly the existence of the interactions between Se atoms. Read the full text of their Full Paper at 10.1002/open.202100017.“… To improve the causality of experimental results, we have proposed a new concept, called “Keisan‐sendo…” Find out more about the story behind the front cover research at 10.1002/open.202100017. 相似文献
114.
Application of 28Mg for characterization of Mg uptake in rice seedling under different pH conditions
N. I. Kobayashi N. Iwata T. Saito H. Suzuki R. Iwata K. Tanoi T. M. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):531-534
The magnesium (Mg) uptake of rice seedlings treated with different pH solutions was investigated using tracer of 28Mg. The application of 28Mg enabled the determination of Mg uptake amount within 15 min of the different pH treatments. The uptake amount of 28Mg and its distribution in rice plants were determined by using the imaging plate. The result demonstrated that the Mg uptake amount was approximately 3 μmol/15 min per plant in 0.27 mM Mg solution at pH 5.6, and this uptake decreased by 30 % at lower pH conditions (pH 4.5). On the contrary, the pH 6.5 condition induced the Mg uptake activity to 4.4 μmol/15 min. The inverse relationship found between proton concentration in nutrient solution and the Mg uptake amount within 15 min of treatment demonstrated that the low pH condition could inhibit the Mg uptake activity as a consequence of the competition between Mg2+ and proton. It is concluded that under low pH conditions, regardless of other factors, there is a decrease of Mg uptake activity in rice roots. 相似文献
115.
Xingzhong Guo Wenyan Li Hui Yang Kazuyoshi Kanamori Yang Zhu Kazuki Nakanishi 《Journal of Sol-Gel Science and Technology》2013,67(2):406-413
An in situ two-step processing using an initial acid catalysis step accompanied by an epoxide-mediated condensation step in the presence of ammonium chloride (NH4Cl) is reported, and macroporous cocontinuous methylsilsesquioxane (MSQ) monoliths have been successfully prepared by this processing. We explain the hydrolysis, gelation behavior and phase separation of MTMS(methyltrimethoxysilane)-MeOH(methanol)-HCl-PO(propylene oxide) system and the in situ effect of NH4Cl, and examine the macroporous morphology and pore structures of MSQ monoliths obtained under different conditions. Macroporous MSQ monolith under optimized conditions possesses a narrow macropore size distribution between 3 to 10 μm, surface area as high as 366 m2·g?1 and minimal shrinkage of only 1 %. 相似文献
116.
Akira Kawashima Prof. Dr. Takayuki Nakanishi Prof. Dr. Tamaki Shibayama Prof. Dr. Seiichi Watanabe Prof. Dr. Koji Fujita Prof. Dr. Katsuhisa Tanaka Prof. Dr. Hitoshi Koizumi Prof. Dr. Koji Fushimi Prof. Dr. Yasuchika Hasegawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(43):14438-14445
Remarkable magneto‐optical properties of a new isolator material, that is, europium sulfide nanocrystals with gold (EuS–Au nanosystem), has been demonstrated for a future photo‐information technology. Attachment of gold particles that exhibit surface plasmon resonance leads to amplification of the magneto‐optical properties of the EuS nanocrystals. To construct the EuS–Au nanosystems, cubic EuS and spherical Au nanocrystals have been joined by a variety of organic linkers, that is, 1,2‐ethanedithiol (EDT), 1,6‐hexanedithiol (HDT), 1,10‐decanedithiol (DDT), 1,4‐bisethanethionaphthalene (NpEDT), or 1,4‐bisdecanethionaphthalene (NpDDT) . Formation of these systems was observed by XRD, TEM, and absorption spectra measurements. The magneto‐optical properties of the EuS–Au nanosystem have been characterized by using Faraday rotation spectroscopy. The Faraday rotation angle of the EuS–Au nanosystem is dependent on the Au particle size and interparticle distance between EuS and Au nanocrystals. Enhancement of the Faraday rotation of EuS–Au nanosystems was observed. The spin configuration in the excited state of the EuS–Au nanosystem was also investigated using photo‐assisted electron paramagnetic resonance. 相似文献
117.
Yue Lu Koichi Nishio Shoichi Matsuda Yuki Toshima Hiroshi Ito Tomohiro Konno Kazuhiko Ishihara Souichiro Kato Kazuhito Hashimoto Shuji Nakanishi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(8):2240-2243
There is growing awareness that circadian clocks are closely related to the intracellular redox state across a range of species. As the redox state is determined by the exchange of the redox species, electrochemically controlled extracellular electron transfer (EC‐EET), a process in which intracellular electrons are exchanged with extracellular electrodes, is a promising approach for the external regulation of circadian clocks. Herein, we discuss whether the circadian clock can be regulated by EC‐EET using the cyanobacterium Synechococcus elongatus PCC7942 as a model system. In vivo monitoring of chlorophyll fluorescence revealed that the redox state of the plastoquionone pool could be controlled with EC‐EET by simply changing the electrode potential. As a result, the endogenous circadian clock of S. elongatus cells was successfully entrained through periodically modulated EC‐EET by emulating the natural light/dark cycle, even under constant illumination conditions. This is the first example of regulating the biological clock by electrochemistry. 相似文献
118.
Li T Garg U Liu Y Marks R Nayak BK Rao PV Fujiwara M Hashimoto H Kawase K Nakanishi K Okumura S Yosoi M Itoh M Ichikawa M Matsuo R Terazono T Uchida M Kawabata T Akimune H Iwao Y Murakami T Sakaguchi H Terashima S Yasuda Y Zenihiro J Harakeh MN 《Physical review letters》2007,99(16):162503
The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112-124) with inelastic scattering of 400-MeV alpha particles in the angular range 0 degrees -8.5 degrees . We find that the experimentally observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in 208Pb and 90Zr very well. From the GMR data, a value of Ktau = -550 +/- 100 MeV is obtained for the asymmetry term in the nuclear incompressibility. 相似文献
119.
Byelikov A Adachi T Fujita H Fujita K Fujita Y Hatanaka K Heger A Kalmykov Y Kawase K Langanke K Martínez-Pinedo G Nakanishi K von Neumann-Cosel P Neveling R Richter A Sakamoto N Sakemi Y Shevchenko A Shimbara Y Shimizu Y Smit FD Tameshige Y Tamii A Woosley SE Yosoi M 《Physical review letters》2007,98(8):082501
The Gamow-Teller strength distributions below the particle threshold in 138La and 180Ta, deduced from high-resolution measurements of the (3He,t) reaction at 0 degrees, allow us to evaluate the role of charged-current reactions for the production of these extremely rare nuclides in neutrino-nucleosynthesis models. The analysis suggests that essentially all 138La in the Universe can be made that way. Neutrino nucleosynthesis also contributes significantly to the abundance of 180Ta but the magnitude depends on the unknown branching ratio for population of the long-lived isomer. 相似文献
120.
Palladium–N‐Heterocyclic Carbene (NHC)‐Catalyzed Asymmetric Synthesis of Indolines through Regiodivergent C(sp3)H Activation: Scope and DFT Study 下载免费PDF全文
Dmitry Katayev Dr. Evgeny Larionov Dr. Masafumi Nakanishi Dr. Céline Besnard Prof. Dr. E. Peter Kündig 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15021-15030
Two bulky, chiral, monodentate N‐heterocyclic carbene ligands were applied to palladium‐catalyzed asymmetric C?H arylation to incorporate C(sp3)?H bond activation. Racemic mixtures of the carbamate starting materials underwent regiodivergent reactions to afford different trans‐2,3‐substituted indolines. Although this CAr?Calkyl coupling requires high temperatures (140–160 °C), chiral induction is high. This regiodivergent reaction, when carried out with enantiopure starting materials, can lead to single structurally different enantiopure products, depending on the catalyst chirality. The C?H activation at a tertiary center was realized only in the case of a cyclopropyl group. No C?H activation takes place alpha to a tertiary center. A detailed DFT study is included and analyses of methyl versus methylene versus methine C?H activation is used to rationalize experimentally observed regio‐ and enantioselectivities. 相似文献