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141.
Shogo Morisako Seiya Watanabe Satoru Ikemoto Satoshi Muratsugu Mizuki Tada Makoto Yamashita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15173-15177
A pincer‐iridium complex bearing a Lewis‐base‐free X‐type alumanyl ligand has been synthesized. X‐ray diffraction, NMR and IR spectroscopy, as well as XANES analysis confirmed its tetrahydrido‐IrV structure and Lewis acidity at the Al center as supported by DFT calculations. The resulting complex was applied as a catalyst for the transfer dehydrogenation of cyclooctane. 相似文献
142.
Nobumasa Chaki Dr. Satoru Muramatsu Yuji Iida Seiya Kenjo Prof. Dr. Yoshiya Inokuchi Prof. Dr. Toshifumi Iimori Prof. Dr. Takayuki Ebata 《Chemphyschem》2019,20(8):996-1000
The S1 electronic state of 7,7,8,8-Tetracyanoquinodimethane (TCNQ) has been investigated by laser induced fluorescence (LIF), dispersed fluorescence (DF) spectroscopy, and lifetime measurements under jet-cooled conditions in the gas-phase. The LIF spectrum showed a weak origin band at 412.13 nm (24262 cm−1) with prominent progression and combination bands involving vibrations of 327, 1098, and 2430 cm−1. In addition, very strong bands appeared at ∼363.6 nm (3300 cm−1 above the origin). Both the LIF and DF spectra indicate considerable geometric change in the S1 state. The fluorescence lifetime of S1 at zero-point level was obtained to be 220 ns. This lifetime is 40 times longer than the radiative lifetime estimated from the S1−S0 oscillator strength. Furthermore, the lifetimes of the vibronic bands exhibited drastic energy dependence, indicating a strong mixing with the triplet (T1) or intramolecular charge-transfer (CT) state. This study is thought to disclose intrinsic nature of TCNQ, which has been well known as a component of organic semiconductors and a versatile p-type dopant. 相似文献
143.
Morita S Suzuki K Machida H Fujimura M Ueno E Ohnishi T Imura C 《Magnetic resonance imaging》2008,26(6):841-846
PURPOSE: To prospectively compare the image acquisition time and image quality obtained by navigator setting under the left hepatic lobe vs. on the right diaphragm on magnetic resonance cholangiopancreatography (MRCP) using a free-breathing navigator-triggered prospective acquisition correction technique (PACE). MATERIALS AND METHODS: Fifty consecutive patients prospectively underwent three-dimensional T2-weighted turbo spin-echo MRCP using PACE with the navigator randomly set either under the left hepatic lobe or on top of the right diaphragm. Image acquisition time and subjective image quality were compared on a five-point scale using Student's t-test and Mann-Whitney's U test, respectively. RESULTS: There was no significant difference for mean acquisition time (6.1+/-1.6 vs. 6.3+/-1.2 min, P=.689) between the left hepatic lobe group and right diaphragm group. Mean subjective image quality was significantly worse in the left hepatic lobe group than in the right diaphragm group (4.1 vs. 4.7, P=.044). CONCLUSION: Setting the navigator under the left hepatic lobe for MRCP using PACE causes the data processing to be more difficult. As well, under current circumstances, it does not contribute to reducing acquisition time or improving the image quality. 相似文献
144.
Junko Hirota Dr. Kazuteru Usui Dr. Yasufumi Fuchi Masaomi Sakuma Shota Matsumoto Ryusuke Hagihara Prof. Dr. Satoru Karasawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14943-14952
Water-soluble donor–acceptor-type fluorophore 15Nap-Cl having two trifluoromethyl groups and a Cl group on a 1,5-aminonaphthyridine framework was prepared. Fluorophore 15Nap-Cl showed strong solvatochromic fluorescence, and, as the solvent polarity increased, a bathochromic shift was observed accompanied by an increase in the fluorescence quantum yield. In addition, in the presence of amines such as ethylamine, diethylamine, and aniline, further considerable bathochromic shifts in the fluorescence were observed. Density functional calculations identified the source of the fluorescence behavior as exciplex formation between 15-Nap-Cl and the corresponding amine. The fluorescence behavior was exploited to fabricate a sensor that can identify various primary, secondary, and tertiary amines. 相似文献
145.
Takahiro Moriyama Daiki Mizukami Dr. Makoto Yoritate Dr. Kazuteru Usui Dr. Daisuke Takahashi Dr. Eisuke Ota Prof. Dr. Mikiko Sodeoka Prof. Dr. Tadashi Ueda Prof. Dr. Satoru Karasawa Prof. Dr. Go Hirai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(11):e202103925
Minimalist photo-reactive probes, which consist of a photo-reactive group and a tag for detection of target proteins, are useful tools in chemical biology. Although several diazirine-based and aryl azide-based minimalist probes are available, no keto-based minimalist probe has yet been reported. Here we describe minimalist probes based on a 2-thienyl-substituted α-ketoamide bearing an alkyne group on the thiophene ring. The 3-alkyne probe showed the highest photo-affinity labeling efficiency. 相似文献
146.
The Electronic State of Hydrogen in the α Phase of the Hydrogen‐Storage Material PdH(D)x: Does a Chemical Bond Between Palladium and Hydrogen Exist?
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Shun Dekura Prof. Hirokazu Kobayashi Prof. Ryuichi Ikeda Prof. Mitsuhiko Maesato Haruka Yoshino Prof. Masaaki Ohba Prof. Takayoshi Ishimoto Dr. Shogo Kawaguchi Prof. Yoshiki Kubota Dr. Satoru Yoshioka Prof. Syo Matsumura Prof. Takeharu Sugiyama Prof. Hiroshi Kitagawa 《Angewandte Chemie (International ed. in English)》2018,57(31):9823-9827
The palladium–hydrogen system is one of the most famous hydrogen‐storage systems. Although there has been much research on β‐phase PdH(D)x, we comprehensively investigated the nature of the interaction between Pd and H(D) in α‐phase PdH(D)x (x<0.03 at 303 K), and revealed the existence of Pd?H(D) chemical bond for the first time, by various in situ experimental techniques and first‐principles theoretical calculations. The lattice expansion, magnetic susceptibility, and electrical resistivity all provide evidence. In situ solid‐state 1H and 2H NMR spectroscopy and first‐principles theoretical calculations revealed that a Pd?H(D) chemical bond exists in the α phase, but the bonding character of the Pd?H(D) bond in the α phase is quite different from that in the β phase; the nature of the Pd?H(D) bond in the α phase is a localized covalent bond whereas that in the β phase is a metallic bond. 相似文献
147.
148.
Tsushima S 《The journal of physical chemistry. B》2008,112(23):7080-7085
Hydrolysis of Th(4+) in aqueous solution was studied by density functional theory (DFT) calculations. First, stable coordination numbers (CNs) of Th(4+) hydrolysis products were studied systematically, and it was found that the CN significantly decreases as a stepwise hydrolysis reaction proceeds. The fourth hydrolysis product Th(OH)4(0) has CN6 with an octahedron coordination. Th(OH)4(OH2)2(0) can readily form a dimer complex Th 2(OH)8(0) via a Th-OH-Th bridging through an exergonic reaction with a Gibbs energy change of -24.0 kJ/mol. Consequently, dimerization inhibits Th(OH)4(0) to stay as stable aqueous species. The calculated result is in agreement with the fact that there is no direct evidence to confirm the presence of Th(OH)4(0) while oligomeric species such as Th 4(OH)16(0) are presumably present. Similar calculations on the Th(4+) disulfato complex reveal that the CN and the average Th-O distance of Th(SO4)2(0) remain almost the same as those in the Th(4+) aquo ion, which is also in agreement with experimental data. 相似文献
149.
This paper is an attempt to provide a connection between qualitative matrix theory and linear programming. A linear program
is said to be sign-solvable if the set of sign patterns of the optimal solutions is uniquely determined by the sign patterns of A, b, and c. It turns out to be NP-hard to decide whether a given linear program is sign-solvable or not. We then introduce a class of
sign-solvable linear programs in terms of totally sign-nonsingular matrices, which can be recognized in polynomial time. For
a linear program in this class, we devise an efficient combinatorial algorithm to obtain the sign pattern of an optimal solution
from the sign patterns of A, b, and c. The algorithm runs in O(mγ) time, where m is the number of rows of A and γ is the number of all nonzero entries in A, b, and c. 相似文献
150.
Kitani S Sugawara K Tsutsumi K Morimoto T Kakiuchi K 《Chemical communications (Cambridge, England)》2008,(18):2103-2105
3-Arylthiochromone derivatives were synthesized as new photolabile protecting groups, in which the photoreactivity was switchable based on oxidation of the sulfur atom (sulfide and sulfone); the protected substrates , released the corresponding alcohols, amines or carbonxylic acids almost quantitatively under UV-light in neutral condition and the photoproduct showed high fluorescence intensity. 相似文献