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101.
Four new iridoid glycosides, named L-phenylalaninosecologanin (1), 7-O-(4-beta-D-glucopyranosyloxy-3-methoxybenzoyl)secologanolic acid (2), 6'-O-(7alpha-hydroxyswerosyloxy)loganin (3) and (Z)-aldosecologanin (5), were isolated, together with a known one, newly named (E)-aldosecologanin (4), from the stems and leaves of Lonicera japonica. Their structures were established on the basis of chemical and spectral data. 相似文献
102.
The aerial parts of Erigeron annuus (L.) PERS., E. philadelphicus L. and E. sumatrensis RETZ. (Compositae) have been investigated chemically. A new sesquiterpenoid, 6beta,14-epoxyeudesm-4(15)-en-1beta-ol (1), and a new diterpenoid, philadelphinone (6), have been isolated from E. philadelphicus. Four new sesquiterpenoids, (7R*)-opposit-4(15)-ene-1beta,7-diol (2), 11-methoxyopposit-4(15)-en-1beta-ol (3), 15-methoxyisodauc-3-ene-1beta,5alpha-diol (4) and 10alpha-hydroxycadin-4-en-15-al (5), have been isolated from E. annuus. Compounds 2 and 4 were also isolated from E. sumatrensis. The structures of the new compounds were elucidated on the basis of their spectral data. 相似文献
103.
Hiroshi Kojima Kosaku Sakeda Teijiro Ichimura Masao Takayanagi 《Journal of Molecular Structure》2003,655(1):185-190
Laser-induced fluorescence (LIF) excitation spectra of m-methylanisole in a supersonic jet were measured. Two series of progressions were observed in the spectrum, originating at 36048 and 36115 cm−1, which were successfully assigned to the transitions to the methyl internal rotational vibronic levels of the two isomers, i.e. cis and trans isomers, with the aid of hole-burning spectrum measurements and quantum-chemical calculations. The progression for the trans isomer was observed up to the 6a1 band, while only the 3a1 band in addition to the 0a1 and 1e bands was observed for the cis isomer. This finding can be explained by the conformational change upon the electronic excitation; the 60° rotation of the methyl torsional angle takes place for the trans isomer but not for the cis isomer. 相似文献
104.
Yasuhiko Kawamura Kohji Akitomo Masaaki Oe Tokunaru Horie Masao Tsukayama 《Tetrahedron letters》1997,38(52):3610-8992
Upon irradiation (>340 nm) of a benzene solution of diazofluorene with di-p-tolyl- or di-p-anisyl disulfide, the corresponding 9,9′-bis(arylmercapto)bifluorenyl was afforded in moderate to good yield accompanied by formation of 9,9′-bis(arylmercapto)fluorene. The major reaction pathway is considered to be a disulfur ylide formation followed by two times of successive Stevens rearrangement or by concerted electron redistribution via [2,3]sigmatropic rearrangement. 相似文献
105.
The growth mechanism of water clusters in carbon nanopores is clearly elucidated by in situ small-angle X-ray scattering (SAXS) studies and grand canonical Monte Carlo (GCMC) simulations at 293-313 K. Water molecules are isolated from each other in hydrophobic nanopores below relative pressures (P/P(0)) of 0.5. Water molecules associate with each other to form clusters of about 0.6 nm in size at P/P(0)=0.6, accompanied by a remarkable aggregation of these clusters. The complete filling of carbon nanopores finishes at about P/P(0)=0.8. The correlation length analysis of SAXS profiles leads to the proposal of a growth mechanism for these water clusters and the presence of the critical cluster size of 0.6 nm leads to extremely stable clusters of water molecules in hydrophobic nanopores. Once a cluster of the critical size is formed in hydrophobic nanopores, the predominant water adsorption begins to fill carbon nanopores. 相似文献
106.
Masao Masamura 《Structural chemistry》2000,11(1):41-45
The purpose of this article is to show that CHELP, CHELPG, and Merz and Kollman undergo error for the charge on atoms of HCOO– (H2O)
n
for n = 1 6. We also demonstrate that the CHELP, CHELPG, and Merz and Kollman show error for the tendency toward change in the charges on carbons for CH3NH+
3 (CH3)2NH+
2 (CH3)3NH+ (CH3)4N+. 相似文献
107.
Yoshikuni Uchida Masao Yoshida Osamu Nishiara Kazunori Matsui 《Journal of Sol-Gel Science and Technology》2003,26(1-3):177-180
Silica gels doped with Cu2+ ions were prepared from the (3-aminopropyl) trimethoxysilane (APTMOS)/tetraethoxysilane (TEOS) systems. Sols showed a broad absorption peak at 640 nm, suggesting 3–5 coordination of the aminopropyl groups to Cu2+. For gels prepared from APTMOS and dried at room temperature, the 640 nm peak decreased and a red-shifted absorption appeared below 400 nm within a few months. The luminescence spectra of the xerogels showed emission bands at 430–470 and 510 nm. The former and latter bands are ascribed to Cu+ monomer and dimer emissions, respectively. These results indicate that Cu2+ ions are reduced to Cu+. When xerogels were prepared from APTMOS/TEOS = 1 (vol/vol), the color of xerogels was blue with an absorption peak at around 670 nm, indicating no reduction of Cu2+ ions. 相似文献
108.
109.
Masao Kaneko 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3-4):357-365
A photosensing device was fabricated based on a photochemical electron transfer reaction. A graphite electrode was coated with bilayer membranes of polymer-pendant Ru(bpy)3 2+ and Prussian Blue (PB) to give a bilayer-coated device. It was irradiated with visible light in an aqueous electrolyte and the induced photocurrent was measured as a function of the applied potential. The excitation of PB was responsible for the anodic photocurrent, while the excitation of the Ru complex mainly induced the cathodic photocurrent by an electron-transfer mechanism. 相似文献
110.
A Nafion film containing tris(2,2′-bipyridine)ruthenium(II) as a luminescence probe was applied to photodetection of oxygen in a gas by utilizing the luminescence quenching by dioxygen. The linear Stern-Volmer plots of the emission intensity with respect to the oxygen concentration allowed quantitative determination of the oxygen. From the emission decay studied by a single-photon counting method, it was concluded that the quenching of the excited state Ru complex by oxygen proceeds by a conventional dynamic mechanism. 相似文献