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Tadahiro Kato Yoshihiro Yamaguchi Nobunori Abe Tadao Uyehara Tsuneo Namai Mitsuaki Kodama Yoshinori Shiobara 《Tetrahedron letters》1985,26(19):2357-2360
Structural elucidation including the absolute configuration was carried out on the trihydroxy C18 -fatty acids isolated from rice plant, Sasanishiki suffered from rice blast disease. 相似文献
43.
Umebayashi Y Mroz B Asada M Fujii K Matsumoto K Mune Y Probst M Ishiguro S 《The journal of physical chemistry. A》2005,109(21):4862-4868
Solvation structure of the zinc(II) ion in N,N-dimethylpropionamide (DMPA) was studied by Raman spectroscopy at varying temperature and by quantum mechanical calculations. No significant ion-pair formation was found for the Zn(ClO4)2 solution in the molality range m(Zn) < 1.5 mol kg(-1), and the solvation number of the zinc(II) ion was determined to be 4, indicating that 6-coordination of DMPA is sterically hindered. Interestingly, DMPA molecules are under equilibrium between planar cis and nonplanar staggered conformers, and the latter is more preferred in the coordination sphere, while the reverse is the case in the bulk. The DeltaG degrees , DeltaH degrees , and TDeltaS degrees values of conformational change from planar cis to nonplanar staggered in the coordination sphere were obtained to be -0.9, -8.5, and -7.5 kJ mol(-1), respectively. Density functional theory (DFT) calculations show that the planar cis conformer is more favorable than the nonplanar staggered one in the 1:2 cluster, as is the case for a single DMPA molecule and H(DMPA)+, indicating that there hardly occurs solvent-solvent interaction through the metal ion in the Zn2+-DMPA 1:2 cluster. On the other hand, the SCF energy of [Zn(planar cis-DMPA)4-n(nonplanar staggered DMPA)n]2+ (n = 0-4) decreases with increasing n, implying that the nonplanar staggered conformer is preferred in the solvate ion. It is thus concluded that solvent-solvent interaction through space, or solvation steric effect, plays a crucial role in the conformational equilibrium in the coordination sphere of the four-solvate metal ion. 相似文献
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Tadahiro Minamikawa Seido Ogura Tetsuo Sakka Yukio Ogata Matae Iwasaki 《国际化学动力学杂志》1994,26(5):561-569
Photolysis of CClF2CH2Cl was studied by 147 nm vacuum ultraviolet irradiation. In the presence of NO; CF2CH2, CF2CHCl, and CClF2CN were produced. These products represent three different reaction paths; the molecular dechlorination, molecular dehydrochlorination, and chlorine radical elimination reactions. The reactant pressure and the addition gas (He or NO) pressure effects upon the product yield were studied. © 1994 John Wiley & Sons, Inc. 相似文献
47.
Hiromu Asada 《Journal of statistical physics》2000,98(3-4):621-637
This paper presents an alternative statistical way to derive the cluster variation method (CVM) for lattice systems. The formulation is developed for a series of different clusters, each of which is the largest overlap cluster between two clusters of the next larger type. We arrive at the CVM expression of the lattice configuration factor by deriving the number of different ways of distributing clusters of a selected type in the lattice so that they overlap each other at the largest overlap clusters in a physically correct manner. The essential assumption employed is that individual overlapping events are statistically independent of each other. This reveals a new statistical aspect of the CVM: The CVM is based on a Bethe tree of clusters of the selected type. 相似文献
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