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71.
Nagawa Y Suga J Hiratani K Koyama E Kanesato M 《Chemical communications (Cambridge, England)》2005,(6):749-751
A novel [3]rotaxane composed of two 25-membered crownophanes and one axle molecule having two anthryl end groups was successfully synthesized via covalent bond formation followed by aminolysis, and can incorporate caesium ion into the space between the two macrocycles as a 1 : 1 sandwich-type complex, whereas it makes a 1 : 2 complex with lithium ion. 相似文献
72.
Xu P Uyama H Whitten JE Kobayashi S Kaplan DL 《Journal of the American Chemical Society》2005,127(33):11745-11753
Nanoscale surface patterning and polymerization of caffeic acid on 4-aminothiophenol-functionalized gold surfaces has been demonstrated with dip pen nanolithography (DPN). The diphenolic moiety of caffeic acid can be polymerized by biocatalysis with laccase or horseradish peroxidase. In the present study, the DPN patterned features were polymerized in situ through the use of the peroxidase. Using samples prepared by DPN, microcontact printing, and adsorption on macroscopic substrates, the products were characterized by electrostatic force microscopy (EFM), MALDI-TOF, X-ray photoelectron spectroscopy (XPS), UV-vis, and FT-IR. The in situ surface polymerization resulted in the formation of a quinone structure, while the phenyl ester formed in bulk polymerization reactions was not detected. A different coupling site was observed when comparing the polymers obtained from solution (bulk) vs the surface DPN reactions. The structural differences were attributed to surface-induced pre-organization and orientation of the monomers prior to the enzymatic polymerization step. The results of this study expand the application of DPN technology to surface modification and surface chemistry reactions wherein stereo-regularity and regioselectivity can be exploited. 相似文献
73.
Masaru Mori Yoshikimi Uyama Yoshito Ikada 《Journal of polymer science. Part A, Polymer chemistry》1994,32(9):1683-1690
To improve the wettability and adhesion, graft polymerization of acrylamide (AAm) and glycidyl methacrylate (GMA) was performed onto the surface of ultra-high modulus polyethylene (UHMPE) fiber pretreated with Ar plasma. Following the plasma treatment and the subsequent exposure to air to introduce peroxides onto the fiber surface, graft polymerization onto the UHMPE fiber was allowed to proceed from the polymer peroxides either in deaerated monomer solution at an elevated temperature (degassing method), or in aerated monomer solution containing riboflavin at 30°C under UV irradiation (photoinduction method). The monomer solution was prepared from water and dioxane for AAm and GMA, respectively. After rigorous removal of homopolymers, surface analysis of the grafted fibers was performed with ATR-FTIR and XPS, which revealed that PAAm and PGMA chains were grafted in the surface region of fibers. The grafting rate of PAAm by the photoinduction method was much higher than that by the degassing method when compared at the same concentration of the AAm solution. The amount of PGMA grafted was greatly affected by UV irradiation time, but depended on plasma treatment time to an insignificant extent if the treatment was carried out for longer than 30 s. Reaction of propylamine with the PGMA-grafted surface resulted in the appearance of a nitrogen peak in the XPS spectrum, suggesting the presence of epoxy groups on the surface of PGMA grafted fiber. © 1994 John Wiley & Sons, Inc. 相似文献
74.
Kazuhisa Hiratani Hideki Sugihara Kazuhiro Taguchi 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(1-2):161-169
Several noncyclic polyether compounds containing oxytrimethylene groups and o-carboxyphenyl terminal group were synthesized. It has been found that they can transport lithium ion selectively in the competitive alkali metal ion transport through liquid membranes. The results of the spectroscopic study, together with inspection on the basis of the CPK model building suggest that these polyethers can form a pseudocavity, in which lithium ion best fits, and then the terminal aromatic rings overlap one another face-to-face to form a stacking structure. By using newly synthesized polyethers, which were designed on the basis of the conformational information, the significant contribution of the structures of these polyethers could be verified. 相似文献
75.
Ferric chloride-catalyzed aerobic oxygenation of 2-halocyclohexanones in methanol to yield adipic acid dimethyl esters. 相似文献
76.
Miyamoto Kazuhisa Matsuoka Sinjirou Miura Yoshiharu Negoro Masaaki 《Applied biochemistry and biotechnology》1992,34(1):459-466
Applied Biochemistry and Biotechnology - Immobilization of algal and bacterial cells was investigated, and found applicable to our hydrogen production system. Both a unicellular green alga,... 相似文献
77.
Kazuhisa Yamaya 《Analytica chimica acta》1979,110(2):233-243
Complete release of water (or of hydrogen in the lattice which is finally released as water) from muscovite containing a large amount of fluorine, requires heating above 1500°C or addition of an appropriate flux. Experimental data from differential thermal analysis, x-ray diffraction patterns and dehydration curves showed that silicon dioxide is a useful flux. Samples are mixed with a 3 : 1 (weight) ratio of silicon dioxide in a platinum crucible and heated inductively in a nitrogen stream at 1200°C. The water released is absorbed in anhydrous (1 + 1) methanol—1, 2-ethanediol and titrated by the Karl Fischer method. For a representative muscovite sample, the water contents were 4.26 ± 0.03% at 1300—1400°C and 4.35 ± 0.08% above 1500°C in the absence of silicon dioxide. When silicon dioxide was added as described, the mean result was 4.33 ± 0.01% at 1200°C (95% confidence level) with a standard deviation of 0.015 and a coefficient of variation of 0.35%. 相似文献
78.
Tachikawa H Iokibe K Azumi K Kawabata H 《Physical chemistry chemical physics : PCCP》2007,9(30):3978-3984
Ab initio and Density Functional Theory (DFT) calculations have been carried out for zinc-water clusters Zn(n)-(H2O)(m) (n = 1-32 and m = 1-3, where n and m are the numbers of zinc atoms and water molecules, respectively) to elucidate the structure and electronic states of the clusters and the interaction of zinc cluster with water molecules. The binding energies of H2O to zinc clusters were small at n = 2-3 (2.3-4.2 kcal mol(-1)), whereas the energy increased significantly in n = 4 (9.0 kcal mol(-1)). Also, the binding nature of H2O was changed at n = 4. The cluster size dependency of the binding energy of H2O accorded well with that of the natural population of electrons in the 4p orbital of the zinc atom. In the larger clusters (n > 20), it was found that the zinc atoms in surface regions of the zinc cluster have a positive charge, whereas those in the interior region have a negative charge with the large electron population in the 4p orbital. The interaction of H2O with the zinc clusters were discussed on the basis of the theoretical results. 相似文献
79.
Tachibana Y Kurisawa M Uyama H Kakuchi T Kobayashi S 《Chemical communications (Cambridge, England)》2003,(1):106-107
Reaction of poly(succinimide) with a mixture of 5-aminopentanol and 6-aminohexanol produced new thermoresponsive polymers based on biodegradable poly(amino acids)s, poly(N-substituted alpha/beta-asparagine)s, showing a clear LCST in water. 相似文献
80.