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141.
The [RuIII(edta)(benzotriazole)]− complex has been investigated in aqueous solution, by means of cyclic voltammetry, stopped-flow
kinetics and spectroelectrochemistry. The formation reaction, starting from [RuIII(edta)H2O]− and benzotriazole, leads essentially
to the N(1) coordinated isomer. In the case of the RuII species, the products exhibit an intramolecular isomerization equilibrium
involving the N(1) and N(2) binding sites, with K12=0.33. A complete set of acid/base and association constants has been obtained
for the RuII and RuIII complexes. The data are coherent with theoretical calculations, reflecting the importance of π-backbonding
interactions in the reduced species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
142.
Lisa Araki Maho Yamaguchi Natsumi Taniguchi Zheng-yun Zhao 《Tetrahedron letters》2004,45(12):2657-2661
A novel C4-linked imidazole ribonucleoside phosphoramidite was designed and successfully synthesized starting from tribenzylribofuranosylimidazole. This phosphoramidite product enables incorporation of the imidazole moiety into an RNA sequence and hence allows study of its role in the general acid and base catalysis of ribozymes. Pivaloyloxymethyl (POM) was first introduced as an N-protecting group for the imidazole ribonucleoside that can be readily removed under mild basic condition. 相似文献
143.
Huzihiro Araki 《Letters in Mathematical Physics》1990,19(2):167-170
The following generalization of an inequality of Lieb and Thirring is proved:
相似文献
144.
Miyuki Hagiwara Toru Tagawa Hideo Amemiya Kunio Araki Isao Shinohara Tsutomu Kagiya 《Journal of polymer science. Part A, Polymer chemistry》1976,14(9):2167-2172
Thermal decomposition of polymer peroxide radicals formed in γ-irradiated polytetrafluoroethylene, ~CF2CF(OO·)CF2~ (radical I) and ~CF2CF2(OO~) (radical II), was studied by mass spectral analysis of the gas evolved in comparison with their photolysis with ultraviolet light. In the thermal decomposition of radicals I and II, CO2 was the most abundant component, with smaller amount of CO, CF2O, and gases present. In the photolysis, CO instead of CO2 was the most abundant in the case of radical I, while in the case of radical II, CO2 was again the main product. When a labeled polymer peroxide radical, ~CF2CF(18O-18O·)CF2~, was treated with heat or ultraviolet light, C18O16O was detected as a main component. In the treatment with ultraviolet light, a large amount of C18O comparable to that of C18O16O was also obtained. The mechanism of main-chain scission of radicals I and II is discussed. 相似文献
145.
146.
Experimental data conclusively shows that the weak van der Waals interactions between alkane molecules, <1.5% the strength of covalent bonding on a per carbon atom basis, modify the carbon 1s near edge X-ray absorption fine structure (NEXAFS) spectrum significantly in ordered solids, both in intensity, spectral shape, peak position, and dichroic signature. This constitutes a further breakdown of the ‘building block’ model, or, more precisely, even a molecular model in interpreting NEXAFS spectra. These observations have significant implications for the interpretation and use of NEXAFS spectra from any crystalline or semi-crystalline macromolecules, small molecules, or other weakly interacting systems. 相似文献
147.
Sandanayaka AS Taguri Y Araki Y Ishi-I T Mataka S Ito O 《The journal of physical chemistry. B》2005,109(47):22502-22512
Photoinduced electron-transfer processes of the newly synthesized [60]fullerene-diphenylbenzothiadiazole-triphenylamine (C60-PBTDP-TPA) triad in polar and nonpolar solvents have been studied by using time-resolved transient absorption and fluorescence measurements from picosecond to microsecond regions. By fluorescence lifetime measurements in picosecond time regions, excitation of the charge-transfer transition of the PBTDP-TPA moiety in C60-PBTDP-TPA induces energy transfer to the C60 moiety generating 1C60*-PBTDP-TPA, competitively with charge separation generating C60*--PBTDP-TPA*+. From 1C60*-PBTDP-TPA, which is generated directly and indirectly, charge separation occurs generating C60*--PBTDP-TPA*+ in polar solvents. The C60*--PBTDP-TPA*+ formed via the singlet excited states decayed within a few nanoseconds as revealed by the picosecond transient absorption spectra. In the nanosecond time region, C60*--PBTDP-TPA*+ is produced slowly, probably via 3C60*-PBTDP-TPA. Lifetimes of such slowly generated C60*--PBTDP-TPA*+ were longer than 1 micros, which are the longest values among the C60-bridge-TPA triad systems reported hitherto at room temperature. Roles of the PBTDP-TPA moiety with twisted intermolecular charge-transfer character playing as energy donor and electron donor in addition to the bridge have been disclosed. 相似文献
148.
Horie R Araki Y Ito O Lee Y Kitagawa T Komatsu K 《The journal of physical chemistry. A》2005,109(28):6140-6146
Photoinduced electron-transfer processes between fullerene (C60) and 1,8-bis(dimethylamino)naphthalene, which is called a proton-sponge (PS), have been investigated by means of laser flash photolysis in the presence and absence of CF3CO2H. For a mixture of C60 and PS, the transient absorption spectra showed the rise of the C60 radical anion with concomitant decay of the C60 triplet (3C60), suggesting that photoinduced intermolecular electron transfer occurs via 3C60 in high efficiency in polar solvent. For a covalently bonded C60-PS dyad, photoinduced intramolecular charge-separation process takes place via the excited singlet state of the C60 moiety, although charge recombination occurs within 10 ns. For both systems, electron-transfer rates were largely decelerated by addition of a small amount of CF3CO2H, leaving the long-lived 3C60. These observations indicate that the energy levels for charge-separated states of the protonated PS and C60 become higher than the energy level of the 3C60 moiety, showing low donor ability of the protonated PS. Thus, intermolecular electron-transfer process via 3C60 for C60-PS mixture and intramolecular charge-separation process via 1C60-PS for C60-PS dyad were successfully controlled by the combination of the light irradiation with a small amount of acid. 相似文献
149.
Palladium-catalyzed oxidative alkynylation of alkenes using tert-propargylic alcohols as alkynylation reagents via C-C bond cleavage under an oxygen atmosphere affords the corresponding ene-yne compounds. 相似文献
150.
A new composite material constituted by mu-{5,10,15,20-tetra(4-pyridyl)porphyrinato cobalt(iii)}-tetrakis-{chloro-bis-(2,2'-bipyridine)ruthenium(ii)} complex (or CoTRP) and cobalt oxide, exhibiting high stability and sensitivity for the quantification of hydrogen peroxide, was obtained by the electrochemical polymerization of the tetraruthenated cobalt porphyrin in alkaline medium. The optimized experimental conditions for the preparation of the modified glassy carbon electrodes and for analysis of H2O2 were carefully determined. Fast sequential analysis (120 determinations h(-1)) in a wide linear dynamic range (5.0 x 10(-7) mol L(-1) to 2.0 x 10(-3) mol L(-1)), with high sensitivity and low detection limit (2.0 x 10(-7) mol L(-1)), was achieved by using these electrodes and the batch injection analysis (BIA) technique. Such characteristics allied to a good stability were explored for the specific determination of hydrogen peroxide in six commercial cosmetics and pharmaceutical product samples, giving results in excellent agreement with those obtained by the spectrophotometric method. 相似文献
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