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91.
Murahashi T Higuchi Y Katoh T Kurosawa H 《Journal of the American Chemical Society》2002,124(48):14288-14289
The linear sandwich tripalladium complexes [Pd3{Ar(CH=CH)4Ar}2[BArf]2 (Ar = Ph, p-t-Bu-C6H4, p-styryl-C6H4) undergo photoinduced isomerization involving face-inversion of the tetraene ligands. Irradiation of these complexes with visible light (>510 nm) resulted in rac (staggered sandwich) to meso (eclipsed sandwich) isomerization. The structures of rac and meso isomers are determined by X-ray crystallographic analyses. 相似文献
92.
93.
94.
Kato N Sakayanagi M Nakayama T Nishimura H Ogamo A 《Journal of chromatography. A》2002,973(1-2):159-166
A novel detection method for 21 different anions by thin-layer chromatography is presented. Anions on the target plate form salts with amine in a developing solvent and are visualized after staining with citric acid-acetic anhydride reagent as white spots contrasting against a pale red-pink background. This method has particularly high sensitivity for anions of chlorate, sulfate, phosphate, chromate and dichromate (0.02-0.05 microg). The method is demonstrated to efficiently detect toxic arsenite in curry sauce as an example application. The proposed method offers highly efficient indirect detection for a wide range of anions, and serves as a purification procedure for the preparation of anionic sample solutions for other analytical methods. 相似文献
95.
Vyaselev O Arai K Kobayashi K Yamazaki J Kodama K Takigawa M Hanawa M Hiroi Z 《Physical review letters》2002,89(1):017001
We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K. 相似文献
96.
Liquid crystal induced circular dichroism (LCICD) measurements were made to investigate the pretransitional phenomena in the SA phase just above the SA-S*C and SA-S*CA phase transitions of both the first and the second order. The pretransitional LCICD in SA was observed in the second order phase transition to S*c and S*cA, suggesting the existence of a dynamic helical structure in SA. Such behaviour disappears when the transition is of the first order. It seems that the handedness of the dynamic helix in SA is the same as that in S*c even when the lower temperature phase is S*cA. This is explained as a result of a dominant contribution of ferroelectric soft mode. 相似文献
97.
Hiroshi Ohguro Norihiko Yoshida Hideo Shindou John W. Crabb Krzysztof Palczewski Motoyuki Tsuda 《Photochemistry and photobiology》1998,68(6):824-828
Abstract— Light-dependent phosphorylation of rhodopsin (Rho) is a first step in the desensitization of the signaling state of the receptor during vertebrate and invertebrate visual transduction. We found that only 358 Ser of the photoac-tivated octopus Rho (oRho*) was phosphorylated by octopus rhodopsin kinase (oRK). Tryptic truncation of the C-terminal PPQGY repeats of oRho that follow the phosphorylation region did not influence spectral or G-protein activation properties of oRho but abolished phos phorylation. Despite significant structural differences between oRK and mammalian RK, these results provide i further evidence of the importance of singly phosphorylated species of Rho* in the generation of arrestin binding sites. 相似文献
98.
The absorption maxima of the fluorescence spectra of the berberine series alkaloids are broadly distributed between 360 and 560 mμ. The fluorescence spectra of most substances of this series are very monotonous one having a single peak, the spectra of tetrahydrocoptisine and tetrahydroepiberberine are quite exceptional and consist of two wavy bands. The introduction of the auxochrome group into the molecule of “proto” compounds causes the decreasing of the fluorescence intensity and this effect is strongest in case of transition from protoberberine to berberine. That, tetrahydropalmatine does not show the distinct fluorescence spectrum band is the only incomprehensible fact. 相似文献
99.
Hideo Sambe 《Chemical physics》1981,59(3):315-327
A semi-empirical theory for transition metal complexes is presented. Unusual aspects of the theory are (1) employment of Xα theory, (2) adoption of theoretical exchange parameter, (3) exclusion of (n + 1)s and (n + 1)p atomic orbitals of a nd-transition metal, and (4) variation of atomic orbitals in LCAO method. Also, an improved Mulliken approximation is proposed and used to simplify the LCAO-Xα equations. 相似文献
100.