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91.
Reported here is the preparation and property of 2D coordination networks composed of rodlike ligands with ethylene glycol side chains (1). Two 2D coordination networks, [[Co(1)2(H2O)2](NO3)2.1.5H2O]n and [[Ni(1)2(H(2)O)2](NO3)2.1.5H2O]n, have been synthesized and characterized by single-crystal X-ray diffraction, TG, DSC, UV-vis spectroscopy, and magnetic measurements. The structural analyses clarified that infinite 1D hydrogen-bond arrays composed of ethylene glycol chains contribute to the stabilization of 2D coordination frameworks, keeping the environment of substitution-active metal sites unchanged. They are more stable than a similar square-grid coordination network that does not possess an ethylene glycol chain on the ligand. We also succeeded in the direct observation of a reversible apical-ligand-exchange reaction at the cobalt(II) and nickel(II) ions in a single-crystal-to-single-crystal fashion because of the considerable stability as well as moderate flexibility of the framework. The cobalt-containing coordination network crystal showed chromic behavior depending on temperatures. Crystallographic and spectroscopic studies revealed that the color change of the crystal was attributed to the ligand-exchange process between H2O and a NO3 anion on the cobalt metal. Magnetic measurements indicated weak antiferromagnetic nearest-neighbor spin coupling between cobalt(II) ions. 相似文献
92.
Yoshida N Abe Y Shigeta H Nakajima A Ohsaki H Hashimoto K Watanabe T 《Journal of the American Chemical Society》2006,128(3):743-747
Flat films of methyl methacrylate-fluoroalkyl methacrylate copolymers were prepared, and their hydrophobicity was investigated. It was revealed that the F concentration directly affects the static hydrophobicity on the flat polymer surface in a systematic manner. Furthermore, the sliding behavior of a water droplet on these surfaces depends on the static hydrophobicity; the sliding motion changes from constant velocity to constant acceleration with an increase in the water contact angle. 相似文献
93.
Yoshihisa Kurosaki Dr. Toshiya Sagisaka Tomoo Matsushima Prof. Takashi Ubukata Prof. Yasushi Yokoyama 《Chemphyschem》2020,21(13):1375-1383
A chiral and thermally irreversible photochromic fulgide derivative incorporating an (R)-binaphthol unit in its acid anhydride moiety was used for the photoswitching of the pitch length of cholesteric liquid crystals. Since the absorption maximum wavelengths of both thermally stable photoisomers are nearly in the UV region (quasi-stealth photochromism), it can be exposed to visible light without inducing photochromic reactions. Therefore, when the photoswitching molecule is added to a permanent cholesteric liquid crystal whose reflection light wavelength is in the visible region, the UV light-induced photochromic reaction of the photoswitching molecule changes the wavelength of the reflection light in the visible light region. We have succeeded in regulating the color of cholesteric liquid crystalline cells between red and blue upon UV light irradiation. Attempts to introduce this system in polymer dispersed cholesteric liquid crystals are also described. 相似文献
94.
Naoya Yoshida Yuu Abe Hiroaki Shigeta Kazuyuki Takami Hisashi Osaki Toshiya Watanabe Kazuhito Hashimoto Akira Nakajima 《Journal of Sol-Gel Science and Technology》2004,31(1-3):195-199
Transparent hydrophobic polymer coating was prepared from methacrylate copolymer with molecular modeling in order to improve hydrophobicity and durability. Organic-inorganic hybridization improved the durability of the thin films. Furthermore the control of hydrophobicity and water droplet sliding properties of the flat coating was successfully performed. Water droplet sliding angle depended on the chemical structure of the materials, not on the hydrophobicity, while sliding motion simply depended on the hydrophobicity. 相似文献
95.
Jiye Jin Toshiya Hiroi Kiyohito Sato Tomoo Miwa Toyohide Takeuchi 《Analytical sciences》2002,18(5):549-554
In this study, a wall-jet flow cell with a GRC (graphite reinforced by carbon) electrode was designed for the amperometric detection of phenol and chlorophenols in liquid chromatography. The voltammetric responses of these analytes at the GRC electrodes are very similar to those at conventional glassy carbon electrodes. As the GRC electrodes were made of the same materials as commercially available mechanical pencil leads, they exhibit the advantages of low cost, simple surface renewability, lower residual current, and good electrode-to-electrode reproducibility, and thus can be used as disposable-type electrodes. Chromatographic separations of phenol, o-chlorophenol (o-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were achieved with an ODS column using a mobile phase containing a mixture of CH3CN and H20 (40:60) containing 25 mM L-(+)tartaric acid (pH = 4.5). Amperometric detections were based on the electrochemical oxidation of these compounds around +0.9 V vs. Ag/AgCl. Under the optimized conditions, linear calibrations were obtained in a range up to 100 microM for phenol, o-CP, 2,4-DCP, 2,4,6-TCP, and 200 microM for PCP, with the correlation coefficients r2 of 0.9992, 0.9997, 0.9986, 0.9992, and 0.9968, respectively. The chromatographic detection limits for the tested analytes were obtained at pmol levels. 相似文献
96.
We investigate the oxidation process of a platinum surface by using the density functional theory approach under the periodic boundary condition. This oxidation process has received much attention because it is an initial step in the dissolution of platinum catalysts in polymer electrolyte fuel cells. In this research, we determine the optimized structure of ?? -PtO2-like and ??-PtO2-like oxidized platinum surfaces, which have recently been proposed on the basis of in situ X-ray diffraction analysis, at the Kohn Sham density functional theory (KS-DFT) generalized gradient approximation (GGA) level of theory. We discuss the phase transition from the ??-PtO2-like surface to the ??-PtO2-like surface, including the place-exchange reaction between oxygen and platinum atoms. We propose an intermediate structure in the phase transition, and show that the ??-PtO2-like structure can be formed directly from this intermediate structure. 相似文献
97.
Ichikawa Y Matsuda Y Okumura K Nakamura M Masuda T Kotsuki H Nakano K 《Organic letters》2011,13(10):2520-2523
The first nonracemic synthesis of (+)-geranyllinaloisocyanide, starting with (-)-lactic acid methyl ester, has been accomplished by exploiting a [3.3] sigmatropic rearrangement of allyl cyanate. The synthesis enables assignment of the S configuration of the C(3) isocyano substituted, quaternary stereogenic center in natural geranyllinaloisocyanide. 相似文献
98.
Tomohiko Nakajima Tetsuo Tsuchiya Toshiya Kumagai 《Applied Physics A: Materials Science & Processing》2011,104(3):981-985
Conducting LaNiO3 thin films have been fabricated on the borosilicate glass substrates with and without the uniaxial oriented RbLaNb2O7 seed layer by an excimer laser assisted metal organic deposition process with a KrF laser irradiation at 400°C in air. The
LaNiO3 thin film prepared on the seed layer had a very high Lotgering factor at F(100)=0.971, indicating highly (100)-oriented growth. The obtained LaNiO3 thin films with and without the seed layer showed low resistivity values, 4.42 and 1.02 mΩ cm at room temperature, respectively.
The ρ value of the (100)-oriented LaNiO3 film on the seed layer was comparably lowered to that of the films prepared at high process temperatures reported in the
previous reports. 相似文献
99.
Tong Y Tyrode E Osawa M Yoshida N Watanabe T Nakajima A Ye S 《Langmuir : the ACS journal of surfaces and colloids》2011,27(9):5420-5426
The composition and structure of a binary mixed self-assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APS, NH(2)(CH(2))(3)Si(OCH(2)CH(3))(3)) and octadecyltrimethoxysilane (ODS, CH(3)(CH(2))(17)Si(OCH(3))(3)) on a silicon oxide surface have been characterized by water contact-angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and sum frequency generation (SFG) vibrational spectroscopy. XPS demonstrated that APS in the mixed SAM is significantly enriched in comparison to that in solution, indicating the preferential adsorption of APS during the SAM formation. AFM observations showed that the mixed SAM becomes rougher. SFG revealed that the coadsorption of APS induced a conformation disordering in the ODS molecules present in the mixed SAM. The surface enrichment of APS has been explained in terms of differences in the surface adsorption rates of the two components as well as in the self-congregation states of APS molecules in the bulk solution. Furthermore, the structure of the water molecules on the mixed SAM surface in contact with the aqueous solutions at different pH's has also been studied. The results indicate that the mixed-SAM modified surface is positively charged at pH < 5 and negatively charged at pH > 7. 相似文献
100.
Kozawa Takahiro Kondo Akira Fukuyama Kayo Naito Makio Koga Hideyuki Shimo Yusuke Saito Toshiya Iba Hideki Inda Yasushi Oono Tomomi Katoh Takashi Nakajima Kousuke 《Journal of Solid State Electrochemistry》2019,23(4):1297-1302
Journal of Solid State Electrochemistry - All-solid-state Li batteries are suitable for the application of 5 V-class cathode materials that can provide high energy densities. However, it is hard to... 相似文献