Identification of Al(III) species in a solution containing equimolar concentrations of Al(III) and citric acid using varying-temperature 27Al NMR spectrometry.

27Al NMR spectra of an equimolar (10 mM) Al(III)-citrate system were obtained at different temperatures. The linewidths of the signals decreased in the spectra recorded at elevated temperatures, which enabled us to unequivocally identify the resonance lines. From the spectrum recorded at 65 approximately C, a mononuclear Al(III)-citrate complex was identified at a solution pH of 3.0 in addition to trinuclear Al(III)-citrate complex, which dominated at pH 4.0.     

Addition reactions of cyclooctatetraene with 1,3-diphenylisobenzofuran the benzene ring as dienophile in a [4+2] cycloaddition reaction

Addition reactions of cyclooctatetraene with 1,3-diphenylisobenzofuran resulted in the formation of three 1:1 cycloadducts, 1, 2, and 3, and a 1:2 cycloadduct, 4. Single crystal x-ray analysis established 3 to be a cage compound formed by an unprecedented [4+2] cycloaddition reaction of 1 in which the double bond of the benzene moiety acted as the dienophile.     

Studies of the polymerization of diallyl compounds. XXVII. Copolymerization of diallyl tartrate with several vinyl monomers

The radical copolymerization of diallyl tartrate (DATa) (M₁) with diallyl succinate (DASu), diallyl phthalate (DAP), allyl benzoate (ABz), vinyl acetate (VAc), or styrene (St) was investigated in order to disclose in more detail the characteristic hydroxyl group's effect observed in the homopolymerization of DATa. In the copolymerization with DASu or DAP as a typical diallyldicarboxylate, the dependence of the rate of copolymerization on monomer composition was different for different copolymerization systems and unusual values larger than unity for the product of monomer reactivity ratios, r₁r₂, were obtained. In the copolymerization with ABz or VAc (M₂), the r₁ and r₂ values were estimated to be 1.50 and 0.64 for the DATa/ABz system and 0.76 and 2.34 for the DATa/VAc system, respectively; the product r₁r₂ for the latter copolymerization system was found again to be larger than unity. In the copolymerization with St, the largest effect due to DATa monomer of high polarity was observed. Solvent effects were tentatively examined to improve the copolymerizability of DATa. These results are discussed in terms of hydrogen-bonding ability of DATa.     

Near-infrared spectroscopy of torbernites and metatorbernites

A suite of torbernites and metatorbernites have been analysed by near-infrared spectroscopy. The spectra of torbernites and metatorbernites in the first HOH fundamental overtone are different and the spectra of torbernites of different origins in the 6000-7500 cm(-1) region vary. NIR spectroscopy provides a method of studying the hydration of cations in the interlayer of torbernite. NIR spectroscopy shows that the spectra of torbernites from different origins in the water HOH first fundamental overtone and combination regions are different. This difference implies the hydration of cations is different for torbernite minerals. The structural arrangement of the water molecules in the interlayer is sample dependent. The NIR spectra of metatorbernites are different from that of torbernites and a similarity of the spectra of metatorbernites suggests that the water structure in metatorbernites is similar.     

Synthesis and Odor Evaluation of Stereoisomers of Imine Derivatives in Roasted Spotted Shrimp

All possible stereoisomers of imine derivatives 1 – 4 , which have the characteristic roast odor of seafood, were synthesized. As a result of odor evaluation of all isomers, we found that each isomer has a different and characteristic odor of roasted seafood.     

Serially coupled capillary columns supercritical fluid chromatography with midpoint pressure control

Two capillary columns of different polarities were coupled in series by means of a coupling restrictor. The pressure of the first column and the midpoint pressure (between the coupling restrictor and the second column) were controlled independently of each other using two pumps. The selectivity of this separation system was highly dependent on the pressure difference and could be continuously changed between those of two columns. The pressure difference could be changed even in course of separation for fine tuning of the selectivity. Several examples were shown to demonstrate the utility of this method.     

Synthesis of 1,6-dihydropyrimidines via copper-catalyzed multistep cascade reactions between O-propargylic aldoximes and isocyanates

Multi-step cascade reactions of O-propargylic oximes with isocyanates were carried out in the presence of copper catalysts to afford the corresponding 1,6-dihydropyrimidines in good yields. The multi-step reactions consisted of a 2,3-rearrangement, a [3+2] cycloaddition, decarboxylative ring opening involving a 1,4-hydrogen shift, and a 6π-electrocyclization.     

Construction of a dimethyl sulfoxide sensor based on dimethyl sulfoxide reductase immobilized on a au film electrode.

A novel dimethyl sulfoxide (DMSO) sensor using DMSO reductase and film electrodes was constructed. The Au and Ag electrodes were fabricated on slide glass by vacuum deposition and the application of a photolithographic technique. The micro-chamber (4 x 50 x 1 mm, volume 200 microl) was fabricated on a poly(dimethylsiloxane) (PDMS) polymer. The Pt electrode was implanted in a PDMS polymer. DMSO reductase was immobilized on a Au film electrode with bovine serum albumin (BSA)-glutaraldehyde. This sensor could determine DMSO in an unpurged aqueous solution with glucose oxidase (GOD) and catalase (CAT) for oxygen removal. The DMSO sensor showed a linear response within 1 mM DMSO with a correlation coefficient of 0.999. The detection limit was 200 microM (3sigma), and the sensitivity was 23.8 mA M(-1) cm(-2). The relative standard deviations at each concentration were within 3.6%.