Synthesis of chiral 2-(anilinophenylmethyl)pyrrolidines and 2-(anilinodiphenylmethyl)pyrrolidine and their application to enantioselective borane reduction of prochiral ketones as chiral catalysts

Chiral diamines, 2-(anilinophenylmethyl)pyrrolidines and 2-(anilinodiphenylmethyl)pyrrolidine, were prepared from N-(tert-butoxycarbonyl)pyrrolidine or (S)-proline as a starting material, respectively. These chiral diamines were efficient for the catalytic enantioselective borane reduction of acetophenone. Using (S)-2-(anilinodiphenylmethyl)pyrrolidine, chiral secondary alcohols were obtained from prochiral ketones with good to excellent enantiomeric excesses (up to 98% ee).     

Benzothiadiazole-based dyes that emit red light in solution,solid, and liquid state

In this paper, we report the preparation and red-light-emitting behavior of benzothiadiazole–tris(alkyloxy)phenylethene dyes. In solution, we observed an efficient red light emission with high fluorescence quantum yields (up to 0.78). With increase in solvent polarity, the emission bands shifted to longer wavelengths accompanied by a large Stokes shift of up to 152 nm. A moderate fluorescence quantum yield of 0.52 could be achieved even in the polar solvent dimethylformamide. Red light emission with good fluorescence quantum yields (up to 0.50) was also observed in the bulk solid, liquid, and film state.     

Efficient partial hydrogenation of trichloromethyl to gem-dichloromethyl groups in platinum on carbon-catalyzed system

While gem-dichloromethyl groups can be directly synthesized by the mono-dechlorination of the corresponding trichloromethyl groups, the suppression control of the over-reduction to form chloromethyl or methyl functionalities is quite difficult. We have established the efficient and widely applicable mono-dechlorination method of the trichloromethyl groups to form the corresponding gem-dichloromethyl groups using platinum on carbon in dimethylacetamide as a specific solvent at 25 °C under a hydrogen atmosphere. The mono-dechlorination of the α,α,α-trichloromethylcarbonyl groups smoothly proceeded by the use of platinum on carbon as a catalyst in a highly chemoselective manner, while the efficient mono-dechlorination of the alkyl- and aryl-trichloromethyl groups required the combined use of Bu₃SnH.     

Structure of tecophilin,a tri-caffeoylanthocyanin from the blue petals of Tecophilaea cyanocrocus, and the mechanism of blue color development

The pigment, tecophilin, in blue flowers of Tecophilaea cyanocrocus was isolated and the structure was determined to be 3-O-(6-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-7-O-(6-O-(4-O-(2-O-(4-O-β-d-glucopyranosyl-(E)-caffeoyl)-6-O-(4-O-β-d-glucopyranosyl-(E)-caffeoyl)-β-d-glucopyranosyl)-(E)-caffeoyl)-β-d-glucopyranosyl)delphinidin. The reproduction experiment of the same color as petals according to the results of chemical analysis and measurement of vacuolar pH of blue cells clarified that the blue color solely develops by tecophilin without interaction of metal ions nor co-pigments. ¹H NMR analysis and CD spectrum indicate the co-existence of clockwise intermolecular self-association of the delphinidin nuclei and intramolecular π–π stacking between the chromophore and caffeoyl residues to derive bathochromic shift of the absorption spectrum and stabilize the color by preventing hydration reaction.     

Intermittent transport associated with the geodesic acoustic mode near the critical gradient regime

Turbulent transport near the critical gradient in toroidal plasmas is studied based on global Landau-fluid simulations and an extended predator-prey theoretical model of ion temperature gradient turbulence. A new type of intermittent transport associated with the emission and propagation of a geodesic acoustic mode (GAM) is found near the critical gradient regime, which is referred to as GAM intermittency. The intermittency is characterized by new time scales of trigger, damping, and recursion due to GAM damping. During the recursion of intermittent bursts, stationary zonal flow increases with a slow time scale due to the accumulation of undamped residues and eventually quenches the turbulence, suggesting that a nonlinear upshift of the critical gradient, i.e., Dimits shift, is established through such a dynamical process.     

Photo-alignment Property of Azobenzene-containing Polyimide Films Swollen by Alkyl-amine

Photo-alignment efficiency of polyimide containing azobenzene in the backbone structure (Azo-PI) is significantly enhanced by exposing the precursor (polyamic acid: Azo-PAA) film to alkyl-amine vapor prior to photo-alignment. In this study, we have investigated the relationships between the alkyl-amine vapor treatment time, the swelling ratio of Azo-PAA films, and the photo-induced in-plane anisotropy. We found that: the Azo-PAA film swells on exposure to alkyl-amine vapor, and the swelling finally saturates; and the photo-induced in-plane anisotropy is correlated very closely with the swelling ratio. In addition, we pointed out the importance of the process order of alkyl-amine vapor treatment and photo-alignment.     

Palladium‐Catalyzed Direct Thiolation of Aryl CH Bonds with Disulfides

A catalytic variant of the direct thiolation of arenes, bearing directing groups, with disulfides or thiols has been developed under palladium and copper co‐catalysis. Both sulfenyl moieties of the disulfide could be incorporated into the thiolated products, therefore, the reactions reached completion with only half an equivalent of disulfide, with respect to the starting arene. Experimental evidence suggested that the reaction proceeds through a Pd^II/Pd^IV mechanism.     

Novel Method for the Fabrication of a Charge‐Transfer Complex Crystal by Photoirradiation

A novel method for the fabrication of a charge‐transfer complex crystal was developed. Photoirradiation of a solution of TPP[Co(tbp)(CN)₂] and TPP[Co(Pc)(CN)₂] (tbp=tetrabenzoporphyrin, Pc=phthalocyanine, TPP=tetraphenylphosphonium) gave a molecular conducting crystal of a charge‐transfer complex TPP[Co(tbp)(CN)₂]₂, which was produced by the process in which the photoexcited electron in tbp was transferred from the LUMO of tbp to that of Pc.     

Fe K‐Edge X‐ray Absorption Fine Structure Determination of γ‐Al2O3‐Supported Iron‐Oxide Species

The structure of FeO_x species supported on γ‐Al₂O₃ was investigated by using Fe K‐edge X‐ray absorption fine structure (XAFS) and X‐ray diffraction (XRD) measurements. The samples were prepared through the impregnation of iron nitrate on Al₂O₃ and co‐gelation of aluminum and iron sulfates. The dependence of the XRD patterns on Fe loading revealed the formation of α‐Fe₂O₃ particles at an Fe loading of above 10 wt %, whereas the formation of iron‐oxide crystals was not observed at Fe loadings of less than 9.0 wt %. The Fe K‐edge XAFS was characterized by a clear pre‐edge peak, which indicated that the Fe?O coordination structure deviates from central symmetry and that the degree of Fe?O?Fe bond formation is significantly lower than that in bulk samples at low Fe loading (<9.0 wt %). Fe K‐edge extended XAFS oscillations of the samples with low Fe loadings were explained by assuming an isolated iron‐oxide monomer on the γ‐Al₂O₃ surface.     

Determination of various inorganic anions and organic acids in the atmospheric particulate matter using capillary zone electrophoresis with indirect UV detection

Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of inorganic anions and organic acids using a mixed solution of 2,6-pyridinedicarboxylic acid and cetyltrimethylammonium hydroxide as the background electrolyte (BGE). The parameters which influence the separation, such as indirect UV detection wavelength, BGE conditions, applied voltage and extraction conditions were investigated. Thirteen inorganic anions and organic acids were detected within 20 min. The calibration curves of each analyte were linear with correlation coefficients greater than 0.991. The relative standard deviations (n = 10) of the peak areas ranged from 0.6% to 3.3%. The detection limits for these species ranged from 0.4 to 1.4 mg/L at a signal-to-noise ratio of 3. The recovery rate of each analyte was more than 80% under optimised extraction conditions, except for nitrite. The proposed method was applied towards the analysis of inorganic anions and organic acids in the atmospheric particulate matter using an Andersen sampler. The particle size of the particulate matter was determined, but not the size of the anions.