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171.
Tanaka Y Hoshino W Shimizu S Youfu K Aratani N Maruyama N Fujita S Osuka A 《Journal of the American Chemical Society》2004,126(10):3046-3047
When heated, bis-Cu(II) octaphyrin(1.1.1.1.1.1.1.1) is quantitatively split into two Cu(II) porphyrins both in solution and film states, which is accompanied by large absorption spectral changes. 相似文献
172.
cis-Decalin (2) and perylene (3) are co-enclathrated by a self-assembled M6L4-coordination cage (1) to give 1 superset(2.3) although each of them is not enclathrated. This phenomenon is termed as AND bimolecular recognition because enclathration occurs only if 2 and 3 coexist. Cage 1 also coenclathrates azulene (8) and 1,4-naphthoquinone (9) to give 1 superset(8.9). In this case, 1 superset(8)2 and 1 superset(9)2 are formed by treating 1 with 8 and 9 individually. This case is termed as OR bimolecular recognition because enclathration occurs if 8 or 9 exists. Accordingly, we have shown that the self-assembled cage 1 experiences both AND and OR bimolecular recognition. 相似文献
173.
K.?MizoguchiEmail author S.?Fujita M.?Nakayama 《Applied Physics A: Materials Science & Processing》2004,78(4):461-464
We report the first observation of coherent phonons in crystalline lead phthalocyanine (PbPc) films grown on a (0001) sapphire substrate by using a pump–probe technique. Coherent phonon oscillations corresponding to intermolecular (lattice) vibrations in the PbPc film are observed in the frequency region from 1 to 5 THz. It is found that the intensities of coherent phonons are resonantly enhanced at the exciton energies of the Q band observed in the absorption spectrum. PACS 78.47.+p; 78.66.-w; 82.53.Xa; 78.40.Me 相似文献
174.
Tomohisa Yasuhara Katsumi Nishimura Ken-ichi Yamada Kiyoshi Tomioka 《Tetrahedron letters》2004,45(15):3043-3045
(±)-γ-Lycorane 3 was synthesized in 52% overall yield via seven steps from 5 by employing the highly stereoselective nitro-Michael cyclization of 5 to 9 and diastereoselective conjugate addition of aryllithium to a nitroolefin 10 as two key steps. 相似文献
175.
Takeishi S Rant U Fujiwara T Buchholz K Usuki T Arinaga K Takemoto K Yamaguchi Y Tornow M Fujita S Abstreiter G Yokoyama N 《The Journal of chemical physics》2004,120(12):5501-5504
DNA oligo-nucleotides, localized at Au metal electrodes in aqueous solution, are found to be released when applying a negative bias voltage to the electrode. The release was confirmed by monitoring the intensity of the fluorescence of cyanine dyes (Cy3) linked to the 5' end of the DNA. The threshold voltage of the release changes depending on the kind of linker added to the DNA 3'-terminal. The amount of released DNA depends on the duration of the voltage pulse. Using this technique, we can retain DNA at Au electrodes or Au needles, and release the desired amount of DNA at a precise location in a target. The results suggest that DNA injection into living cells is possible with this method. 相似文献
176.
Shigendo Enomoto Ken-ichi Kumagai Taro Tamura Miki Hasegawa Kyoko Nakada Toshihiko Hoshi Michio Kobayashi 《Monatshefte für Chemie / Chemical Monthly》2004,29(1):471-481
Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The 1H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the 1H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of CS symmetry, in which the benzene molecule mainly interacts with the electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the 1H NMR spectral shifts mentioned above and the experimentally predicted CS structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure. 相似文献
177.
In this article, we report successful preparation of dense [(Na0.5K0.5)1−xSrx](Nb1−xTix)O3 (x=0.005-0.100) ceramics by ordinary sintering in air. The dependence of phase structure on doping content of SrO and TiO2 has been determined by the X-ray diffraction technique. It was found that the crystal structure changed from orthorhombic to tetragonal at x≈0.040. Dielectric study revealed that the dielectric relaxor behavior was induced by doping of SrO and TiO2 into (Na0.5K0.5)NbO3. The samples in the composition range from x=0.005 to 0.020 exhibited excellent electrical properties, piezoelectric constant of electromechanical planar and thickness coupling coefficients of kp=26.6-32.5% and kt=39.8-43.8%. The results show that the [(Na0.5K0.5)1−xSrx](Nb1−xTix)O3 ceramics are one of the promising lead-free materials for electromechanical transducer applications. 相似文献
178.
Itami K Mitsudo K Fujita K Ohashi Y Yoshida J 《Journal of the American Chemical Society》2004,126(35):11058-11066
Some circumstantial evidence for the directing effect of the 2-pyridylsilyl group in the Ru-catalyzed intermolecular Pauson-Khand-type reaction (PKR) of alkenyl(2-pyridyl)silane, alkyne, and carbon monoxide has been provided. Most importantly, we have succeeded in isolating several monometallic Ru complexes relevant to the catalytic reaction: Ru(vinylsilane)(CO)(3) complexes and ruthenacyclopentene. While the stoichimetric reaction of the Ru(vinylsilane)(CO)(3) complex with an alkyne led to the formation of the corresponding cyclopentenone (PKR product) at 100 degrees C, the ruthenacyclopentene intermediate was quantitatively produced at 50 degrees C. This complex was also converted to a cyclopentenone upon heating at 100 degrees C. Moreover, it was also found that the Ru(vinylsilane)(CO)(3) complex and ruthenacyclopentene serve as catalysts in intermolecular PKR. 相似文献
179.
Lucarelli A Lupi S Ortolani M Calvani P Maselli P Capizzi M Giura P Eisaki H Kikugawa N Fujita T Fujita M Yamada K 《Physical review letters》2003,90(3):037002
While there is increasing evidence for antiferromagnetic (AF) ordering in the Cu-O planes of high-T(c) superconductors, either static or fluctuating, there is no direct evidence so far for the charge stripes that should separate the AF domains. By investigating the optical response of La2-xSrxCuO4 for 0相似文献
180.
A diode-pumped chirped-pulse regenerative amplifier with a cooled Yb:YLF crystal has been developed. The output pulse energy is 30 mJ at 20-Hz repetition rate. A high effective extraction efficiency of 68% is obtained, which is attributed to reduced saturation fluence at low temperature and to a high effective pulse energy fluence during regenerative amplification. After pulse compression by use of a parallel grating pair, 18-mJ pulse energy and 795-fs pulse duration are obtained. 相似文献