Muon science in J-PARC

The intensity of proton accelerator has attained to the order to mega-watt, and several MW-class proton accelerators start to operate in the world. J-PARC is a complex of three accelerators, and generates a variety of secondary beams, i.e. muon beam, neutron beam, meson beam and neutrino beam. The muon facility is established in order to provide a pulsed muon beam for various experimental programs. The first muon beam is transported to the experimental area in September 2008. Although the accelerator is still under commissioning, and the beam power doesn’t reach the design value of 1 MW yet, the world strongest pulsed muon beam will be provided shortly. In this paper, we review the muon beam line in J-PARC, and discuss evolved scientific programs.     

Hyperfine-structure-induced purely long-range molecules

We have experimentally observed and theoretically identified a novel class of purely long-range molecules. This novel purely long-range state is formed due to a very weak hyperfine interaction that is usually treated only as a small perturbation in molecular spectra. Photoassociation spectroscopy of ultracold ytterbium (171Yb) atoms with the 1S0-3P1 intercombination transition presents clear identification of molecular states and the shallowest molecular potential depth of about 750 MHz among the purely long-range molecules ever observed.     

Hydrogen bonding in sodium alanate: a muon spin rotation study

We have detected the occurrence of hydrogen bonding involving an interstitial positive muon situated between hydrogen atoms of two independent alanate anions in sodium alanate (NaAlH4). Ti doping, which is known to dramatically improve the hydrogen cycling performance of NaAlH4, reduces the kinetic barrier of the transition of the muon from the muon-dialanate state to a mobile interstitial state. This observation strongly suggests that hydrogen bonding is the primary bottleneck for hydrogen release or uptake in sodium alanate, which might be common to other complex hydrides.     

Au–Ag Nanoflower Catalysts with Clean Surfaces for Alcohol Oxidation

Shape‐controlled metal nanocrystals, such as nanowires and nanoflowers, are attractive owing to their potentially novel catalytic properties and bimetallic nanocrystals composed of two distinct metals are expected to act as highly active catalysts. However, their catalytic activities are limited because of the capping agents adsorbed on the metal surfaces, which are necessary for the preparation and dispersion of these nanocrystals in solvents. Therefore, the preparation of bimetallic shape‐controlled noble metal nanocrystals with clean surfaces, devoid of almost all capping agents, are expected to have high catalytic activity. Herein, we report the preparation of bimetallic Au–Ag nanoflowers using melamine as the capping agent. The bimetallic Au–Ag nanoflowers with a clean surface were subsequently obtained by a support and extraction method. The bimetallic nanoflowers with a clean surface were then used for the aerobic oxidation of 1‐phenylethyl alcohol and they exhibited high rates for the formation of acetophenone compared to Au nanoflowers and spherical nanoparticles with almost the same size and Au/Ag ratio. We also show that Au–Ag nanoflowers containing only 1 % Ag (Au₉₉–Ag₁NFs) exhibit the highest rate of acetophenone formation among Au–Ag nanoflowers with different Au/Ag ratios owing to an increase in the electron density of the Au atoms that act as active sites for the oxidation of 1‐phenylethyl alcohol.     

Organic/inorganic supramolecular channel frameworks containing a photosensitive azobenzene molecule as an included guest

Two independent channel frameworks are occupied by photoactive E-azobenzene in an unprecedented one-dimensional zigzag motif and thus form virtual three-dimensional supramolecular host-guest networks.     

Structure and synthesis of nectrisine, a new immunomodulator isolated from a fungus.

The structure of a novel immunomodulator, nectrisine (1), has been elucidated on the basis of chemical and spectroscopic evidence. Its absolute stereochemistry was predicted on the basis of the dibenzoate chirality rule and finally confirmed by a synthesis from D-glucose.     

Determination of radioruthenium using a polyethylene film

A simple method is described for the determination of radioruthenium. A solution containing radioruthenium is placed in a conical flask with small amounts of sulfuric acid, silver nitrate, and potassium periodate. The mouth of the flask is covered with a thin polyethylene film, which is fixed with a soft rubber band, and the flask is heated for 2 hrs on a water bath. Radioruthenium is oxidized to tetroxide, evaporated by steam-distillation, and fixed quantitatively on the inner surface of the polyethylene film as a firm black stain. Contamination ratios of other nuclides are under 2·10^?4.     

Reaction of (dialkylaminomethyl)trimethylsilanes with benzyne

Reactions of (dialkylaminomethyl)trimethylsilanes [dimethylamino-, diethylamino-, pyrrolidino- and morpholino-] with benzyne in THF gave two types of aniline derivatives: N-alkyl-N-(1-trimethylsilylalkyl)anilines and N-alkyl-N-trimethylsilylmethylanilines. From (piperidinomethyl)trimethylsilane, however, unexpected 1-(α-trimethylsilylbenzyl)piperidine was obtained together with N-(4-pentenyl)-N-trimethylsilylmethylaniline.     

Novel thiophene oligomers containing a redox active hexaarylethane unit

[structure: see text] Novel thiophene oligomers containing a redox active hexaarylethane unit have been prepared as a new class of molecular wires having a large electrochemical bistability and definitely characterized by using single-crystal X-ray structure analysis and redox potential measurements. They constitute reversible redox pairs with the corresponding bis(thioxanthyl) dications by undergoing C-C bond making/breaking. They show unique electrochromism and a fluorescence change during interconversion.