Design of Thermochromic Luminescent Dyes Based on the Bis(ortho‐carborane)‐Substituted Benzobithiophene Structure

To obtain solid‐state emissive materials having stimuli‐responsive luminescent chromic properties without phase transition, benzobithiophenes modified with two o‐carborane units having various substituents in the adjacent phenyl ring in o‐carborane were designed and synthesized. Their emission colors were strongly affected not only by the substituents at the para‐position of the phenyl ring but also by molecular distribution in the solid state. In particular, the emission colors were changed by heating without crystal phase transition. It was proposed that their thermochromic properties were correlated not with isomerization but with the molecular motion at the distorted benzobithiophene moiety.     

Control of Circularly Polarized Luminescence by Orientation of Stacked π‐Electron Systems

Planar chiral building blocks based on 4,7,12,15‐tetrasubstituted [2.2]paracyclophanes were obtained via a synthetic route involving an optical resolution step. Planar chiral enantiomers, comprising two fluorophores that were stacked to form a V‐shaped higher‐ordered structure, were synthesized from these building blocks. The V‐shaped molecules emitted intense circularly polarized luminescence (CPL). Their chiroptical properties were compared with those of X‐shaped molecules bearing the same two fluorophores stacked together. The CPL sign of the X‐shaped molecule was opposite to that of the V‐shaped molecule, which is supported by the theoretical results, indicating that the CPL sign can be controlled by the orientation of the stacked fluorophores.     

Proton transfer in water–hydroxyl mixed overlayers on Pt(1 1 1): Combined approach of laser desorption and spatially-resolved X-ray photoelectron spectroscopy

Proton transfer in water–hydroxyl mixed overlayers on a Pt(1 1 1) surface was studied by a combination of laser induced thermal desorption (LITD) method and spatially-resolved X-ray photoelectron spectroscopy (micro-XPS). The modulated pattern OH + H₂O/H₂O/OH + H₂O was initially prepared by the LITD method; vacant area with a 400 μm width was first formed in the mixed OH + H₂O overlayer by irradiation of focused laser pulses, and followed by refilling the vacant area with pure H₂O. Spatial distribution changes of OH and H₂O were measured as a function of time with the micro-XPS technique, which indicated that H₂O molecules in the central region flow into the OH + H₂O region. From quantitative analyses using a diffusion equation, we found that the proton transfer in the mixed overlayer consists of at least two pathways: direct proton transfer from H₂O to OH in the nearest site and the proton transfer to the next-nearest site via H₃O⁺ formation. The time scale of first and second path was estimated to be 5.2 ± 0.9 ns and 48 ± 12 ns at 140 K, respectively. In the presence of water capping layer, however, the rate of proton transfer is reduced by an order of magnitude, which would be explained by peripatetic behavior of proton into H₂O capping layer.     

Synthesis and Properties of Oligophenylene‐Layered Polymers

We report syntheses of phenylene‐, biphenylene‐, and terphenylene‐layered polymers with a xanthene scaffold by the modified Suzuki‐Miyaura coupling reaction. Their optical properties were studied in detail. The polymer end‐capped by nitrobenzene units, which act as fluorescence quenchers, exhibited the photo‐excited energy transfer from the layered oligophenylenes to the terminal units.

     

Precise determination of elastic constants by high‐resolution inelastic X‐ray scattering

Inelastic X‐ray scattering (IXS) measurements have been performed on an MgO single crystal in order to evaluate IXS as a methodology for accurate and precise determination of elastic constants and sound velocities. By performing the IXS experiment using a 12‐analyzer array, the complete set of single‐crystal elastic constants of MgO were determined to a precision better than 0.8% (sound velocities to better than 0.2%). The results are consistent with values in the literature. The precision and accuracy of this work, which is significantly better than other published work to date, demonstrates the potential of IXS in determining elastic properties.     

Fluoropyrroles and tetrafluoroporphyrins

Photolysis of pyrrole-β-diazonium tetrafluoroborates gave β-fluoropyrroles. These were further converted to 1,3,5,7-tetrafluoroporphyrins, the first example of ring-fluorinated porphyrin derivatives.     

Arsenic accumulation by arsenic-tolerant freshwater blue-green alga (Phormidium sp.)

Accumulation, biomethylation and excretion of arsenic by the arsenic-tolerant freshwater blue–green alga, Phormidium sp., which had been isolated from an arsenic-polluted environment, were investigated. The cellular growth curves were in fair agreement with a ‘logistic curve’ equation. The growth increased with an increase in the surrounding arsenic concentration up to 100 m?g g^?1. The cells survived even at 7000 m?g g^?1. The arsenic concentration of the cells increased with an increase of the surrounding arsenic concentration up to 7000 m?g g^?1. Phosphorus concentrations in the medium affected the growth and arsenic accumulation. No arsenic was accumulated by cells killed by ethanol. The arsenic was methylated to the extent of 3.2% of the total arsenic accumulated. When the cells were transferred into an arsenic-free medium, 85% of the arsenic accumulated was excreted; 58% of the excreted arsenic was in methylated form implying extensive methylation in the arsenic-free medium.     

Structure of patulolide a,a new macrolide from penicillium urticae mutants

A new macrolide named patulolide A was isolated from the culture broth of $\text{Penicillium urticae}$ mutants. The structure and absolute configuration of it was determined.     

Effective lagrangian for supersymmetric theories with intermediate breaking scale

We investigate effective lagrangians in supersymmetric models broken spontaneously at an intermediate energy (～ μ ? M_GUT). It is shown to all orders in perturbation theory that the low-energy interactions of light particles are described by an effective lagrangian with explicit but soft supersymmetry breaking of order μ² / M_GUT.