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1.
Yasuhiro Maeda Masaki Yumoto Norihito Saito Takayo Ogawa Kazuo Kurokawa Akihiko Nakano Masafumi Yamashita Satoshi Wada 《Optical Review》2010,17(3):305-308
We have achieved a rapid and random wavelength tuned picosecond pulsed laser and a widely tunable UV-blue picosecond pulsed
laser by using the intracavity second harmonic generation of the laser. The tuning range was from 384 to 434 nm with picosecond
pulse oscillation. In addition, we demonstrated biological imaging using a fluorescent protein excited by the widely tunable
UV-blue picosecond pulsed laser. We found that the laser is suitable for biological imaging using the fluorescent protein
as an excitation light source without damages. 相似文献
2.
Ebata T Hashimoto T Ito T Inokuchi Y Altunsu F Brutschy B Tarakeshwar P 《Physical chemistry chemical physics : PCCP》2006,8(41):4783-4791
IR-UV double resonance spectroscopy and ab initio calculations were employed to investigate the structures and vibrations of the aromatic amino acid, L-phenylalanine-(H(2)O)(n) clusters formed in a supersonic free jet. Our results indicate that up to three water molecules are preferentially bound to both the carbonyl oxygen and the carboxyl hydrogen of L-phenylalanine (L-Phe) in a bridged hydrogen-bonded conformation. As the number of water molecules is increased, the bridge becomes longer. Two isomers are found for L-Phe-(H(2)O)(1), and both of them form a cyclic hydrogen-bond between the carboxyl group and the water molecule. In L-Phe-(H(2)O)(2), only one isomer was identified, in which two water molecules form extended cyclic hydrogen bonds with the carboxyl group. In the calculated structure of L-Phe-(H(2)O)(3) the bridge of water molecules becomes larger and exhibits an extended hydrogen-bond to the pi-system. Finally, in isolated L-Phe, the D conformer was found to be the most stable conformer by the experiment and by the ab initio calculation. 相似文献
3.
Redox‐Driven Symmetry Change for Terbium(III) Bis(porphyrinato) Double‐Decker Complexes by the Azimuthal Rotation of the Porphyrin Macrocycles
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Dr. Ken‐ichi Yamashita Takayo Yamanaka Naoya Sakata Prof. Dr. Takuji Ogawa 《化学:亚洲杂志》2018,13(13):1692-1698
Molecular structures for three oxidation forms (anion, radical, and cation) of terbium(III) bis(porphyrinato) double‐decker complexes have been systematically studied. We found that the redox state controls the azimuthal rotation angle (φ) between the two porphyrin macrocycles. For [TbIII(tpp)2]n (tpp: tetraphenylporphyrinato, n=?1, 0, and +1), φ decreases at each stage of the oxidation process. The decrease in φ is due to the higher steric repulsion between the phenyl rings on the porphyrin macrocycle and the β hydrogen atoms on the other porphyrin macrocycle, which results from the shorter interfacial distance between the two porphyrin macrocycles. Conversely, φ=45° for both [TbIII(oep)2]?1 and [TbIII(oep)2]0 (oep: octaethylporphyrinato), but φ=36° for [TbIII(oep)2]+1. Theoretical calculations suggest that the smaller azimuthal rotation angle of the cation form is due to the electronic interaction in the doubly oxidized ligand system. 相似文献
4.
5.
Takayo Takigawa Hideo Ogawa Masanori Nakamura Katsutoshi Tamura Sachio Murakami 《Fluid Phase Equilibria》1995,110(1-2):267-281
Molar excess enthalpies HmE, isobaric heat capacities CP,mE, volumes VmE and isothermal compressibilities κTE for the 1,3-dioxane(3DX) + cyclohexane mixture were measured at 298.15 K, in order to compare to those of the 1,4-dioxane(4DX) + cyclohexane mixture. HmE is endothermic and the maximum value about 1.5 kJ mol−1 at x ≈ 0.45, and lower than that of the 4DX mixture by about 80 J mol−1. VmE is positive over the whole concentration and the maximum value is about 0.85 cm3 mol−1 at x ≈ 0.45, and lower than that of the 4DX mixture. The above results suggest the energetic unstabilization, resulting in the volume expansion in the mixture. CP,mE shows the characteristic W-shaped concentration dependence, which has maximum at x ≈ 0.45 and two minima at x ≈ 0.1 and 0.9. The maximum CP,mE value for 3DX mixture shifts toward the positive side, compared to that of 4DX mixture. κTE were estimated from speeds of sound, densities, thermal expansion coefficients and isobaric heat capacities of the pure component liquids and the mixtures. The κTE result shows the positive concentration dependence over the whole composition range. The 3DX mixture has the similar thermodynamic properties to the 4DX mixture, despite that 4DX is the nonpolar solvent and 3DX is the dipolar liquid. this means that there exists the local dipolar interaction between 4DX molecules, and the prevalence of “microheterogeneity” in the both mixtures. 相似文献
6.
Tomihiko Ohsawa Takao Kobayashi Yuko Mizuguchi Takayo Saitoh Takeshi Oishi 《Tetrahedron letters》1985,26(49):6103-6106
Toluene radical anion generated from potassium metal/dicyclohexano-18-crown-6/toluene system has been proved to be highly effective for reductive decyanation reaction of primary, secondary and tertiary cyanides. 相似文献
7.
Liu Q Inoue T Kirchhoff JR Huang C Tillekeratne LM Olmstead K Hudson RA 《Journal of chromatography. A》2004,1033(2):349-356
The separation of two highly negatively charged enantiomeric organic disulfates containing two chiral centers was investigated by capillary electrophoresis using cyclodextrin based chiral selectors added to the run buffer. The optimum separation for the enantiomers was achieved in less than 3 min at 25 degrees C with a run buffer of 10 mM glycine pH 2.4 and 5 mM QA-beta-CD, which is a positively charged quaternary ammonium beta-cyclodextrin derivative. The method resulted in baseline resolution, excellent linearity, and highly reproducible migration times allowing facile evaluation of the enantiomeric purity of the individual isomers. Detection limits for the enantiomeric pair were determined to be 0.3 ng/microl (S/N = 3). The nature of the selector-enantiomer interaction and a quantitative measurement of the apparent stability constants that governed chiral discrimination of the enantiomers with QA-beta-CD were also investigated by UV-Vis spectroscopy and electrospray ionization mass spectrometry. 相似文献
8.
Takayo Moriuchi-Kawakami Rie Aoki Kazuhiro Morita Haruhisa Tsujioka Keiichi Fujimori Yasuhiko Shibutani Toshiyuki Shono 《Analytica chimica acta》2003,480(2):291-298
A conformational analysis was performed on two crown ethers (12-crown-3 and 12-crown-4) using a combination of semi-empirical and ab initio methods. The lowest conformations of 12-crown-3 and 12-crown-4 were found to have exodentate C3v and C2 structure, respectively. In the case of the sandwich-type complexation, the nucleophilic cavity of 12-crown-3 rather than that of 12-crown-4 seemed to be optimal for complexation with the Na+ ion. Four new bis(12-crown-3) derivatives (1–4) were examined as potential sodium ion-selective ionophores in poly(vinylchloride) (PVC) membrane electrodes. The ion-selective electrode (ISE) based on di(1,5,9-trioxacyclododecanylmethyl) 2-dodecyl-2-methylmalonate (1) had the highest selectivity for the sodium ion among the alkali and alkaline earths studied. The sodium ion selectivity of the ISE based on bis(12-crown-3) derivative 1 was superior to that of the ISE based on the bis(12-crown-4) analogue. 相似文献
9.
Masato Ueda Takahiro Saito Keiichi Fujimori Takayo Moriuchi Yasuhiko Shibutani 《Analytical sciences》2004,20(12):1649-1653
To examine the directivity for improving the silver ion discrimination ability of a Schiff base, three kinds of tridentate ligands were synthesized and compared with the similar quadridentate ligand as the silver ionophore. Among the Schiff base derivatives tested, 3-(2-pyridylethylimino)-2-butanoneoxime, having one oxime and a pyridine substituent, was found to be the best ionophore for a silver-ion electrode. The electrode based on this derivative exhibited good silver-ion selectivity, -log Kpot(Ag+,K+) = 3.8, comparable to that of a quadridentate Schiff base, N,N'-bis(2'-hydroxyimino-1'-phenylpropyleden)-1,3-propanediamine, reported previously, except for a pseudo Nernstian response (35.6 mV decade(-1)) with a wide silver-ion activity change in the activity change from 5.0 x 10(-7) to 7.9 x 10(-2) mol dm(-3). 相似文献
10.
Fukuji Higashi Takayo Shirai Kiyoshi Mitani Kanako Sugishita 《Journal of polymer science. Part A, Polymer chemistry》2001,39(22):3884-3892
A mixture of isophthalic acid (IPA) and terephthalic acid (TPA) was activated by a tosyl chloride/dimethylformamide/pyridine (Py) condensing agent in two steps via the treatment of a mixture of the initially activated IPA/TPA with additional TPA followed by the activation of TPA with the agent. The resulting mixture showed a solubility in Py different from that obtained by the activation of them all at once; the difference might be due to different structures of the aggregates of the activated IPA and TPA at the same composition of the diacids. The structures of the aggregates were evaluated on the basis of melting points and the IR spectra of a mixture of dimethyl esters of IPA and TPA produced by the quenching of the reaction mixtures with methanol. The mixture obtained by two‐step activation showed lower melting points and spectral changes due to enhanced associations of the esters with respect to the mixture prepared by the activation of them all at once. The aggregates were also examined in terms of the distributions of IPA and TPA in thermotropic copolyesters prepared from methylhydroquinone and chlorohydroquinone by their transition temperatures and 13C NMR. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3884–3892, 2001 相似文献