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141.
Kouichi Nakagawa Shozo Tero-Kubota Yusaku Ikegami Nobuaki Tsuchihashi 《Photochemistry and photobiology》1994,60(3):199-204
Abstract Sesamolyl and related phenoxyl radicals were studied by conventional and time-resolved electron paramagnetic resonance (EPR) spectroscopic techniques. Continuous UV irradiation of sesamol in benzene produces two types of radicals. Based on the hyperfine coupling values obtained we determined that one is the neutral sesamolyl radical and the others are the dimer radicals. Comparison was made with related compounds, especially 3,4-dime-thoxyphenol. We found that the 3,4-dimethoxyphenoxyl radical had a shorter lifetime than the neutral sesamolyl radical. The EPR results obtained suggest that a near perpendicular orientation of the oxygen p -orbitals with respect to the benzene ring of sesamol makes the radical more stable. This stability may be important for the antioxidant properties. 相似文献
142.
Kuroda-Sowa T Liu SQ Yamazaki Y Munakata M Maekawa M Suenaga Y Konaka H Nakagawa H 《Inorganic chemistry》2005,44(6):1686-1692
Reaction of [2.2]paracyclophane with silver(I) heptafluorobutyrate (AgC3F7CO2) has isolated three novel networks: [Ag4(pcp)(C3F7CO2)4] x pyrene (1), [Ag4(pcp)(C3F7CO2)4] x phen (phen = phenanthrene) (2), and [Ag4(pcp)(C3F7CO2)4] x fluorene (3), and an intercalation compound [Ag4(pcp)(C3F7CO2)4] x 2benzene (4). All the four complexes exhibit two-dimensional (2D) sheet structures in which AgC3F7CO2 form an infinite chain and pcp acts as linkage. 1, 2, and 3 show 2D flat sheets with cavities in which guest molecules are situated, whereas 4 exhibits 2D zigzag layers between which guest benzene molecules are intercalated. Pcp shows mu-di-eta1-eta2 coordination mode in 1, mu-tetra-eta1 coordination mode in 2 and 3, and mu-tetra-eta2 coordination mode in 4. The reversible guest exchanges were observed between complex 1, 2, or 3 and intercalation compound 4. It is unprecedented for metal-organic inclusion complexes that the guest exchange occurs where the guest is the solute molecule. Furthermore, 4 can release the guest, and the original framework was completely recovered after reincorporation of benzene. It should be noted that 4 can incorporate pyrene, phen, and fluorene to give 1, 2, and 3, respectively, after desorption. 相似文献
143.
Kensuke Kuwamura Tohru Ikegami Sadahiro Masuo Shinjiro Machida Nobuo Tanaka Akira Itaya 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):232-238
The direct photolysis of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solution was investigated under monochromatic ultraviolet (UV) irradiation at 254 nm. ABTS was found to be directly photolyzed by UV irradiation to yield the one-electron oxidized radical, ABTS+, which is a blue-green colored persistent radical species that has strong visible absorption bands. The photochemical production of ABTS+ was strongly dependent on the solution pH and the presence of dissolved oxygen. The presence of dissolved oxygen increased the quantum yields at pH 3, whereas it inhibited the production of ABTS+ at pH 6.5. Spectrophotometric and spectrofluorometric data indicated that ABTS photolysis may occur as a result of the transfer of one-electron between the singlet excited state and the ground state of ABTS. Observations made during UV/H2O2 experiments with ABTS suggested that the dependence of the photoloysis of ABTS on the solution pH and the presence of dissolved oxygen is related to the role of the hydroperoxyl/superoxide radical (HO2/O2−), which appears to be formed via a secondary reaction of the reduced intermediate of ABTS with dissolved oxygen. The proposed photolytic reactions were supported by the observed stoichiometry between the amount of ABTS+ radicals produced and the amount of ABTS molecules decomposed. 相似文献
144.
We give a necessary and sufficient condition for a K?hler manifold of complex dimension n ≧ 2 to be a complex space form in terms of its sectional curvatures, which is an extension of Schur’s lemma. Our study is
related to a congruence theorem for circles in a complex space form
Received: 6 October 2006 相似文献
145.
Sadahiro Saeki 《Journal of Fourier Analysis and Applications》1995,2(1):15-28
Let
and
Under certain conditions on
we shall prove that
converges nontangentially to
at
for
相似文献
146.
147.
This paper consists of two parts. One is to construct a class of helical geodesic equivariant immersions of orderd(⩾3), which are neither Kaehler nor totally real immersions, into complex projective spaces. The other is to show the basic
results about a helix in complex space forms.
This research was partially supported by Grants-in-Aid for Scientific Research (Nos 62740070 and 62740054), Ministry of Education,
Science and Culture and by the Max-Planck-Institut für Mathematik in Bonn. 相似文献
148.
Tadakatsu Mandai Sadahiro Suzuki Atsushi Ikawa Taro Murakami Mikio Kawada Jiro Tsuji 《Tetrahedron letters》1991,32(52):7687-7688
A new synthetic method for polycyclic compounds via the palladium-catalyzed tandem carbonylation and intramolecular Diels-Alder reaction is described. 相似文献
149.
150.
We show that every sufficiently high dimensional Euclidean sphere admits an odd dimensional Riemannian submanifold M having the properties: (1) M is a homogeneous submanifold with nonzero parallel mean curvature vector in the ambient sphere; (2) M is a Berger sphere; (3) M is a Sasakian space form of constant ${\phi}$ -sectional curvature. Note that our manifold M is diffeomorphic but not isometric to a Euclidean sphere. 相似文献