藤田 正博

We synthesized sulfonated poly[(4-phenoxybenzoyl)-1,4-phenylene-co-anthraquinone] copolymers (S-P(PBP-co-ANQ)s) in order to investigate the effect of polycyclic units on the water uptake, dimensional stability, and proton conductivity. The effect of the binding positions of anthraquinone (ANQ) was also investigated by preparing S-P(PBP-co-1,4ANQ) and S-P(PBP-co-1,5ANQ), each with 5 mol% ANQ. Number-average molecular weights and thermal decomposition temperatures of S-P(PBP-co-ANQ)s were about 50-70 kgmol(-1) and 220 degrees C, which were sufficient for polymer electrolyte fuel cell (PEFC) applications. S-P(PBP-co-1,5ANQ) membranes showed higher dimensional stability and proton conductivity than S-P(PBP-co-1,4ANQ) and S-PPBP membranes. The maximum current densities and power densities of S-P(PBP-co-1,5ANQ) fuel cells were 2200mA cm(-1) and 800 mW cm(-2) at 80 degrees C and 100% relative humidity. These results suggest that the improvement of dimensional stability and electrochemical properties is due to strong aggregation of the copolymer chains induced by ANQ at an appropriate coupling position.

Biphasic calcium phosphate (BCP) ceramics with wellcontrolled pores were fabricated by sintering mixtures of synthetic hydroxyapatite (HAp) and deoxyribonucleic acid (DNA). BCP ceramics with macro- and micropores revealed excellent cell proliferation as a result of suitable surface topography and phase composition. © 2013 The Chemical Society of Japan.

Shikimic acid was first isolated in 1885 by Eijkman from the fruit of the Japanese plant Illicium religiosum. Many natural plants contain shikimic acid for biosynthesis as an important intermediate. Roche pharmaceutical uses shikimic acid from star anise as a starting material for production of Tamiflu. However, isolation of star anise from natural resources has been limited. Here we report efficient and new isolation protocol of shikimic acid from Ginkgo biloba leaves utilizing an ionic liquid that dissolves cellulose. Shikimic acid was efficiently extracted and isolated from G. biloba leaves utilizing an ionic liquid 1-butyl-3-methylimidazolium chloride ([bmim]Cl), which is able to dissolve cellulose. Using the ionic liquid at 150 ℃ gave an extraction yield of 2.3% w/w for shikimic acid, which was 2.5 times higher than that for methanol at 80 ℃ (0.93% w/w). Meanwhile, an isolation protocol for obtaining shikimic acid in good yield from the IL phase using an anion-exchange resin Amberlite IRA-400 Cl form was established. The SEM micrograph of the leaves after extraction showed a significantly different morphology, with the larger features completely broken down into much smaller structures, indicating that the G. biloba leaves were much more highly dissolved in [bmim]Cl compared to in methanol The present procedure could lead to a convenient supply of shikimic acid, thus enabling production of greater amounts of the antiviral agent Tamiflu. The protocols are also likely to be applicable to other plant leaves, allowing for isolation of greater quantities of other natural products as well as unknown natural compounds.

Hydrophilichydrophobic block copolymer ionomers based on polyphenylenes with controlled the block lengths were synthesized for the first time by a catalyst-transfer polycondensation of a dibromo phenylene derivative having a neopentyl ester protected sulfonic acid group, followed by the polycondensation of hydrophobic dibromo hexyloxybenzene. The diblock copolymer ionomers were obtained by the removal of neopentyl groups, resulting in clear phase separation dependent on the block lengths. The well-developed microphase separation provided controlled water uptake and sufficiently high proton conductivity, especially at low relative humidity conditions. The fine block copolymerization by using catalyst transfer polycondensation is a promising strategy for the development of hydrocarbon ionomers having well-defined ordered structures with reasonable proton conductivity for fuel cell applications.

Oligothiophene derivatives, 4,4′-bis-(2-aminoethylthienyl)-3,4- ethylenedioxythiophene dihydrohalide (AET-EDOT·HX: X = I, Br), were synthesized by Grignard coupling reactions. The hybrid films of oligothiophene and lead halide were fabricated by casting and spin-coating methods. The effect of halogen species on the optical properties of the perovskites was investigated. The X-ray diffraction profiles of (AET-EDOT)PbX 4 cast films indicated that the layered structures were formed by the self-organization. After hybridization of AET-EDOT·HX with PbX 2, new absorption peaks due to the confined excitons were observed at 400 nm for (AET-EDOT)PbBr 4 film, and at 395 nm for (AET-EDOT)PbI 4 film. These results indicated that the diamino-type oligothiophenes were successfully incorporated into the organic-inorganic layered perovskites. AFM images of (AET-EDOT)PbX 4 cast films showed polycrystalline grains, indicating that the polycrystalline structures covered on the substrate surface. © (2012) Trans Tech Publications, Switzerland.

A chiral polyfluorenethiophene derivative incorporating two different chiral side chains was synthesized via the Suzuki coupling reaction. Upon photoexcitation, thin films of the polymer exhibited efficient circularly polarized luminescence in the visible range, even without thermal annealing. The dissymmetry factor, g lum, of films with thicknesses less than 100nm reached 0.2 at 505 nm. © 2012 The Chemical Society of Japan.

Lithium was electrochemically inserted from a Li(+) ion containing ionic liquid into graphite or tin to observe lithium isotope effects that accompanied the insertion. While no preferential uptake of the lithium isotopes was detected with graphite, the lighter isotope, (6)Li, was preferentially fractionated into tin with the single-stage lithium isotope separation factors, S, ranging from 1.004 to 1.008 at 25 degrees C. It was speculated that a Li(+) ion was inserted into graphite together with an anionic component of the ionic liquid and, upon the reduction of the Li(+) ion to a lithium atom, the anion was released from graphite, while a Li(+) ion alone was inserted into tin. Molecular orbital calculations supported this speculation in a qualitative fashion. (C) 2011 Elsevier Ltd. All rights reserved.

An imidazolium-based zwitterion containing two oxyethylene units was obtained as a colorless liquid at room temperature. The equimolar mixture of the liquid zwitterion and lithium bis(trifluoromethylsulfonyl) amide showed an ionic conductivity of over 10(-4) S cm(-1) at 80 degrees C, which was higher than those of mixtures composed of analogous solid zwitterions.

An ionic liquid having a hydroxyl group, choline bis(trifluoromethylsulfonyl)amide ([N-111(2OH)][N(Tf)(2)]), was synthesized to investigate the effect of hydroxyl groups on the proton transport. 1,1,1-Trifluoro-N-(trifluoromethylsulfonyl)methanesulfoneamide (HN(Tf)(2)) as a proton source was mixed with the choline derivative at various molar ratios. Their thermal properties, viscosities, and ionic conductivities were investigated. [N-111(2OH)][N(Tf)(2)] showed a melting point at 27 degrees C, and its thermal stability was higher than 400 degrees C. The viscosity of [N-111(2OH)][N(Tf)(2)]/HN(Tf)(2) mixtures increased as the acid molar fraction increased. The ionic conductivity of [N-111(2OH)][N(Tf)(2)] was 2.1 x 10(-3) S cm(-1) at 25 degrees C; the ionic conductivity monotonously decreased as the acid molar fraction increased. There was a clear correlation between the ionic conductivity and the viscosity for the mixtures of the choline derivative and the acid. PFG-NMR measurements were carried out to investigate the diffusion behavior of protons. Although the acid and the hydroxyl group were indistinguishable by H-1 NMR, the self-diffusion coefficient of the H-1 of the hydroxyl group and the acid was larger than those of other H-1 nuclei. This difference suggests that a fast intermolecular proton transfer exists between the hydroxyl group and the acid.

Shikimic acid, the starting material in the commercial synthesis of oseltamivir phosphate (Tamiflu (R)), was efficiently extracted and isolated from Ginkgo biloba leaves utilizing the ionic liquid 1-butyl-3-methylimidazolium chloride ([bmim]Cl), which dissolves cellulose.