Study of the suppressed decays B- -->[K+pi-](D)K- and B- -->[K+pi-]Dpi-

We report a study of the suppressed decays B--->[K(+)pi(-)](D)K- and B--->[K(+)pi(-)](D)pi(-), where [K(+)pi(-)](D) indicates that the K+pi(-) pair originates from a neutral D meson. These decay modes are sensitive to the unitarity triangle angle varphi(3). We use a data sample containing 275 x 10(6) BB pairs recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) storage ring. The signal for B--->[K(+)pi(-)](D)K- is not statistically significant, and we set a limit r(B)<0.27 at 90% confidence level, where r(B) is the magnitude of the ratio of amplitudes |A(B--->D 0K-)/A(B--->D0K-)|. We observe a signal with 6.4sigma statistical significance in the related mode, B--->[K(+)pi(-)](D)pi(-).     

Effect of the adiabatic process on the absorption in heavy-ion scattering

We have succeeded in obtaining the optical model potential for ¹²C---¹²C scattering at low incident energies (10 MeV E_cm 20 MeV), by applying the adiabatic approximation to the coupled channels equation. As for this potential inelastic channels of single and mutual excitations of ¹²C^*(2⁺, 4.43 MeV) make a contribution to the real part and not to the imaginary part.     

Alkali metal and alkali metal hydroxide intercalates of 2s-tantalum disulfide

The alkali metal intercalates of the layered compound 2s-tantalum disulfide were prepared from the respective hexamethylphosphoric triamide solutions of the metals. The c-lattice parameters of the intercalates increased with increase in the crystallographic radii of the metals. All intercalates prepared were superconductors, and the transition temperatures increased as the crystallographic radii of the metals became larger. The intercalates reacted with water to produce hydrogen gas and changed to different intercalates. These had properties similar to those of the corresponding alkali metal hydroxide intercalates prepared from aqueous solutions of the metal hydroxides. The alkali metal hydroxide intercalates, on the other hand, were found to be classified into two groups in terms of the c-lattice parameters; one having c-lattice parameters around 23.8 Å and the other 18 Å. Lithium and sodium hydroxide intercalates belong to the former type, and potassium, rubidium and cesium hydroxide intercalates, including ammonium hydroxide, to the latter. Dried lithium and sodium hydroxide intercalates were also classified in the latter group. In the former case the disulfide was found to intercalate the cations, conserving the ice-like structure of the surrounding water molecules. In the latter, the cations were intercalated in their naked or primary hydrated states, and the interlayer distances were governed by cointercalated hydroxide ions. The observed superconducting transition temperatures were similar for the intercalates with c-lattice parameters around 18 Å irrespective of the particular cation.     

One-electron oxidation of anispinacolone with diaroyl peroxides: Mechanistic changeover of the peroxide function from radical to molecular oxidation

Oxidative cleavage of anispinacolone (An₃C·CO·An, An=p-methoxyphenyl) with diaroyl peroxides proceeds by electron-transfer mechanism, which starts with rate-determining decomposition of the peroxide, unimolecular for dibenzoyl and bimolecular for bis(3,5-dinitrobenzoyl) peroxide.     

Undoped Layered Perovskite Oxynitride Li2LaTa2O6N for Photocatalytic CO2 Reduction with Visible Light

Oxynitrides are promising visible‐light‐responsive photocatalysts, but their structures are almost confined with three‐dimensional (3D) structures such as perovskites. A phase‐pure Li₂LaTa₂O₆N with a layered perovskite structure was successfully prepared by thermal ammonolysis of a lithium‐rich oxide precursor. Li₂LaTa₂O₆N exhibited high crystallinity and visible‐light absorption up to 500 nm. As opposed to well‐known 3D oxynitride perovskites, Li₂LaTa₂O₆N supported by a binuclear Ru^II complex was capable of stably and selectively converting CO₂ into formate under visible light (λ>400 nm). Transient absorption spectroscopy indicated that, as compared to 3D oxynitrides, Li₂LaTa₂O₆N possesses a lower density of mid‐gap states that work as recombination centers of photogenerated electron/hole pairs, but a higher density of reactive electrons, which is responsible for the higher photocatalytic performance of this layered oxynitride.     

Manipulating Metal‐to‐Metal Charge Transfer for Materials with Switchable Functionality

Metal‐to‐metal charge transfer (MMCT) describes electron transfer between metal ions, to generate valence isomers with markedly different electronic configurations. In particular, MMCT changes the spin states of single‐metal sites and the coupling interactions between them, while also changing the symmetry in charge distribution. The result is a drastic change in both magnetic and electric properties of the affected material. Moreover, MMCT causes significant variation in bond length and absorption spectra, and induces unusual thermal expansion and photochromic behavior. Thus, materials demonstrating MMCT in response to external stimuli are excellent candidates for switchable multifunctional devices with synergistic responses. In this Minireview, recent progress in utilizing MMCT units as actuators to tune magnetic, electric, thermal expansion, and photochromic properties in cyanide‐bridged systems is highlighted, and emphasis is given to the remaining challenges and future perspectives in the field.     

Croissamide,a proline-rich cyclic peptide with an N-prenylated tryptophan from a marine cyanobacterium Symploca sp.

Croissamide, a proline-rich cyclic peptide that contains an N-prenylated tryptophan, was isolated from a marine cyanobacterium Symploca sp. Its gross structure was determined by spectroscopic analyses, and the absolute configuration was established based on chiral HPLC analyses of acid hydrolysates.