The photoinduced charge separation at the water-porphyrin interface

The photoinduced charge separation and charge transfer at the boundary between a tetraphenylporphine crystal and an aqueous electrode were observed with the porphyrin layers prepared on a gold-coated aluminium foil and on a transparent insulating polymer film.     

Simultaneous determination of preservatives in beverages,vinegar, aqueous sauces,and quasi-drug drinks by stir-bar sorptive extraction (SBSE) and thermal desorption GC-MS

A method for the simultaneous determination of seven preservatives - sorbic acid, benzoic acid, and p-hydroxybenzoic acid ethyl, isopropyl, propyl, isobutyl, and butyl esters - in beverages, vinegar, aqueous sauces, and quasi-drug drinks has been developed using the stir-bar sorptive extraction technique then thermal desorption GC-MS analysis. The extraction conditions - pH, sample volume, extraction temperature, salt addition, and extraction time - were examined. d5-Benzoic acid and p-hydroxybenzoic acid sec-butyl ester were added as surrogate internal standards to compensate for the effect of sample matrix and coexisting analytes on the sorptive extraction. The linearity of the method was good over the concentration range from 1 to 1000 microg mL(-1) for sorbic acid, 10-1000 microg mL(-1) for benzoic acid, and 0.1-100 microg mL(-1) for p-hydroxybenzoic acid ethyl, isopropyl, propyl, isobutyl, and butyl esters, and the correlation coefficients were higher than 0.9984. The limit of detection ranged from 0.015 to 3.3 microg mL(-1). The recoveries (95-105%) and precision (RSD: 0.86-6.0%) of the method were examined by analyzing a sparkling soft drink, white wine, red wine, balsamic vinegar, soy sauce, and quasi-drug drink samples fortified at the 5 to 50 microg mL(-1) level.     

Umpolung of reactivity of allylsilane,allylgermane, and allylstannane via their reaction with thallium (III) salt: a new allylation reaction for aromatic compound

A new direct allylation of the aromatic compound has been developed. A combination of allylsilane, allylgermane, or allylstannane and thallium (III) trifluoroacetate gave rise to an allyl cationic species which was allowed to react with an aromatic compound, a nucleophile, to give allylation product(s) in good yields.     

Reaction of allylsilane with α-nitro olefin and its development to synthesis of cyclopentenone

Michael addition of allylsilane to α-nitro olefin in the presence of AlCl₃ proceeded smoothly at low temperature to give unsaturated nitronic acid, which was converted into the γδ-enone using aqueous Ti (III). Transformation with the latter provided a convenient new synthesis of cyclopentenone.     

Synthesis and Structure of YbCuGe and YbIrGe

The equiatomic ytterbium–transition metal–germanides YbCuGe and YbIrGe were synthesized in single crystalline form from CuGe and IrGe master alloys and ytterbium via the Bridgman technique and they were characterized through their X-ray powder patterns. The structures were refined from X-ray single crystal diffractometer data: NdPtSb type, P6₃mc, a=421.36(8), c=703.9(1) pm, wR2=0.0234, 210 F² values, 11 variable parameters, BASF=0.35(9) for YbCuGe and TiNiSi type, Pnma, a=671.09(6), b=421.55(5), c=757.16(7) pm, wR2=0.0782, 519 F² values, 20 variable parameters for YbIrGe. The copper (iridium) and germanium atoms build up [CuGe] and [IrGe] networks. In YbCuGe the two-dimensional [CuGe] network consists of puckered layers of Cu₃Ge₃ hexagons (247pm Cu–Ge) that are charge balanced and separated by the ytterbium atoms. In contrast, the ordered Ir₃Ge₃ hexagons show a strong orthorhombic distortion and the [IrGe] network is three-dimensional with a distorted tetrahedral germanium coordination around iridium with almost equal Ir–Ge distances (252–259pm). The ytterbium atoms fill cages within this network. The cell volumes of YbCuGe and YbIrGe are indicative for purely trivalent ytterbium.     

Non‐isocyanate synthesis and application of telechelic polyurethanes via polycondensation of diurethanes obtained from ethylene carbonate and diamines

Aliphatic polyurethanes could be obtained in high yield via a non‐isocyanate method based on the self‐polycondensation of dihydroxyurethanes obtained by the reaction of diamines and ethylene carbonate. The polycondensation under a N₂ atmosphere yielded [6,2]polyurethane with a M_n value of 5300 in 87% yield. Two‐step polycondensation, consisting of the polycondensation under a N₂ atmosphere followed by that under reduced pressure, was effective to improve the yield and the molecular weight up to 90% and 10,000, respectively. Although the second polycondensation step at 180 °C was accompanied by formation of urea groups, this side reaction was relatively suppressed at 150 °C. The resulting polyurethane having hydroxyl groups at both of the end groups was converted to polyurethane methacrylate via a reaction with glycidyl methacrylate, and the polyurethane methacrylate served as a crosslinker for radical polymerization of methyl acrylate. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Novel analytical method for the crosslinking process: Infrared thermographic analysis of the thermally latent cationic polymerization of a spiroorthoester and a bifunctional oxetane for the construction of a low‐shrinkage curing system

Thermal behaviors were monitored by infrared thermographic analysis in the copolymerization of a spiroorthoester and a bifunctional oxetane with thermally latent initiators [benzyl tetrahydrothiophenium hexafluoroantimonate (BTHT) and benzyl 4‐hydroxyphenyl methyl sulfonium hexafluoroantimonate (BPMS)]. The copolymerization with BPMS increased the temperature during the copolymerization more than that with BTHT, whereas the exothermicities were lowered with the increase in the initial feed ratio of the spiroorthocarbonate monomer. The high exothermicity in the copolymerization with BPMS is ascribable to the faster propagation of the oxetane monomer with a high heat of polymerization, and this is supported by model reactions and computational calculation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2820–2826, 2007     

Infrared thermographic analysis on copolymerization of spiroorthoester with oxetane

Infrared (IR) thermography was employed to monitor temperature changes during the copolymerization of a spiroorthoester monomer with an oxetane monomer initiated with a benzyl sulfonium salt. The temperature changes in the polymerizations decreased with the increase of the initial feed ratios of the spiroorthocarbonate monomer. For instance, the temperature in the copolymerization of the equimolar mixture of both of the monomers increased only ～1 °C, whereas that in the homopolymerization of the oxetane monomer increased more than 20 °C. This result indicates that the copolymerization employing spiroorthocarbonate monomers effectively suppress temperature increase, which are responsible to shrinkage during cooling. The suppression of polymerization shrinkage by spiroorthocarbonate was also confirmed by density measurement of the polymers using a gas pycnometer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1388–1393, 2007.