A new approach to the spectral study of unstable radicals and ions in solution by the use of an inert gas glovebox system: observation and analysis of the infrared spectra of the radical anion and dianion of p-terphenyl

By using a Fourier-transform infrared spectrometer contained in an inert gas glovebox system (oxygen and water concentrations: <0.1 ppm), high-quality infrared absorption spectra have been observed for the radical anion and dianion of p-terphenyl in tetrahydrofuran solutions. Density functional theory with the B3LYP nonlocal exchange-correlation functional and the 6-311+G** basis set has been used for the calculations of the structures and infrared spectra of the neutral species, radical anion, and dianion of p-terphenyl. The observed infrared spectra of the radical anion and dianion are in good agreement with those calculated by density functional theory. The origin of the strong infrared absorption intensities characteristic of the radical anion and dianion are discussed in terms of changes in electronic structures induced by specific normal vibrations (electron-molecular vibration interaction).     

Palladium-catalyzed C-H activation/intramolecular amination reaction: a new route to 3-aryl/alkylindazoles

A method for the catalytic C-H activation of hydrazone compounds followed by intramolecular amination is described. It requires the use of a catalytic amount of Pd(OAc)2 in the presence of Cu(OAc)2 and AgOCOCF3, which efficiently effects the cyclization to afford variously substituted indazoles. The reactions proceed under relatively mild conditions and thus tolerate a variety of functional groups, including alkoxycarbonyl and cyano groups and halogen atoms.     

Identification of a low plasma-rotation threshold for stabilization of the resistive-wall mode

The plasma rotation necessary for stabilization of resistive-wall modes (RWMs) is investigated by controlling the toroidal plasma rotation with external momentum input by injection of tangential neutral beams. The observed threshold is 0.3% of the Alfvén velocity and much smaller than the previous experimental results obtained with magnetic braking. This low critical rotation has a very weak beta dependence as the ideal wall limit is approached. These results indicate that for large plasmas such as in future fusion reactors with low rotation, the requirement of the additional feedback control system for stabilizing RWM is much reduced.     

The scope and limitation of the regio- and enantioselective hydrolysis of aliphatic epoxides using Bacillus subtilis epoxide hydrolase,and exploration toward chirally differentiated tris(hydroxymethyl)methanol

The substrate specificity of an engineered Bacillus subtilis epoxide hydrolase, which so far had shown high activity and enantioselectivity with 1-benzyloxymethyl-1-methyloxirane, has been studied by altering the methyl substituent into hydrogen, oxygen-containing functionalities, and unsaturated homologs. High enantioselectivity (E = 44) was observed with 1-benzyloxymethyl-1-vinyloxirane with a proper catalytic activity. The elaboration of the reaction conditions and work-up procedures enabled a preparative-scale kinetic resolution, to give (R)-2-benzyloxymethyl-3-butene-1,2-diol and its antipodal (R)-epoxide in high ees.     

A Convenient N-Protection of Pyroglutamate Derivatives

Esters of pyroglutamic acid were N-protected by conventional protective groups (Z. Boc, and COOMe) in high yield, without racemization, using LiHMDS in THF at - 78 °C and ZCl, Boc₂O, and ClCOOMe, respectively.     

The alignment of nematic liquid crystals on photolithographic micro-groove patterns

Abstract

The alignment of nematic liquid crystals on micro-groove patterns was studied. It has been found that the order of the alignments is determined by the edge shape, spacing, and line pitch of the micro-groove patterns. On coarse patterns, with pitches greater than 2 μm, striped patterns of the liquid crystal alignment were observed using polarized light which manifested different orientations of the liquid crystals on the top, edge, and bottom of the grooves, respectively. On fine patterns, with pitches less than 2 μm, a uniform device-quality alignment has been realized, with which twisted nematic cells were constructed in combination with the rubbed alignment layer on the opposite substrate. Their viewing angle characteristics and tilt orientations of the director were also investigated.     

Determination of the Diameter‐Dependent Onset Potential for the Oxygenation of SWCNTs

The evaluation of the diameter‐dependent onset potential for the oxygenation of a SWCNT (single‐walled carbon nanotube) is an important issue because its chemical and physical properties, such as chemical reactivity, electronic conductance, and optical characteristics, would be changed. We investigated the diameter‐dependent onset potential for the oxygenation of SWCNTs in neutral aqueous solution by using in situ Raman spectroelectrochemical measurements, which was explained quantitatively in terms of the strain energy per carbon atom. These results will be useful for the fabrication of materials in which CNTs are used as a platform for applications such as fuel cells, capacitors, and Li‐ion batteries.     

Muon transfer from excited states of muonic hydrogen atoms studied by X-ray measurement

Muon transfer from proton to deuteron was examined with muonic X-rays. The parameter q _1s was determined directly and the time spectra of the X-rays were analyzed for effects of the muon transfer reaction. This revised version was published online in August 2006 with corrections to the Cover Date.