Aromatic substitution of olefins. Arylation with anilines via the C-N bond cleavage in the presence of palladium(II) acetate

A new aromatic substitution reaction of styrene by arylamines such as aniline, (unp)-toluidine, (unp)-anisidine, (unp)-chloroaniline, and (unp)-nitroaniline in the presence of palladium(II) acetate has been found to give (E)-stilbene, (E)-(unp)-methylstilbene, (E)-(unp)-methoxystilbene, (E)-(unp)-chlorostilbene, and (E)-(unp)-nitrostilbene, respectively, in modest yields.     

The Last Step of Kanamycin Biosynthesis: Unique Deamination Reaction Catalyzed by the α-Ketoglutarate-Dependent Nonheme Iron Dioxygenase KanJ and the NADPH-Dependent Reductase KanK

Mystery solved: Using heterologous expression, the activities of two enzymes exclusively belonging to the kanamycin biosynthetic pathway have been identified in vitro. A distinctive reaction mechanism to produce kanamycin is proposed and the previously unknown catalytic deamination activity of KanJ dioxygenase is uncovered.     

Fission track–secondary ion mass spectrometry as a tool for detecting the isotopic signature of individual uranium containing particles

A fission track technique was used as a sample preparation method for subsequent isotope abundance ratio analysis of individual uranium containing particles with secondary ion mass spectrometry (SIMS) to measure the particles with higher enriched uranium efficiently. A polycarbonate film containing particles was irradiated with thermal neutrons and etched with 6 M NaOH solution. Each uranium containing particle was then identified by observing fission tracks created and a portion of the film having a uranium containing particle was cut out and put onto a glassy carbon planchet. The polycarbonate film, which gave the increases of background signals on the uranium mass region in SIMS analysis, was removed by plasma ashing with 200 W for 20 min. In the analysis of swipe samples having particles containing natural (NBL CRM 950a) or low enriched uranium (NBL CRM U100) with the fission track–SIMS method, uranium isotope abundance ratios were successfully determined. This method was then applied to the analysis of a real inspection swipe sample taken at a nuclear facility. As a consequence, the range of ²³⁵U/²³⁸U isotope abundance ratio between 0.0276 and 0.0438 was obtained, which was higher than that measured by SIMS without using a fission track technique (0.0225 and 0.0341). This indicates that the fission track–SIMS method is a powerful tool to identify the particle with higher enriched uranium in environmental samples efficiently.     

Liquid Crystalline Properties of Some Derivatives with a Long Lateral Alkoxyl Group

Abstract

This paper describes the liquid the crystalline properties of 4-(4-alkoxy-phenoxycarbonyl)phenyl 4-bromo-3-alkoxy-(2), 4-cyano-3-alkoxybenzoates(3), and 2-methyl-3-alkoxybenzoates(4). 2 and 3 are essentially smectogenic, while 4 are nematogenic. The difference in the mesomorphic properties is discussed in terms of their molecular geometrical characteristics estimated by a semi-empirical molecular orbital calculation.     

Highly enantioselective reformatsky reaction of ketones: chelation-assisted enantioface discrimination

[reaction: see text] Highly enantioselective Reformatsky reaction of ketones was accomplished using cinchona alkaloids as chiral ligands. Chelation with the sp(2)-nitrogen adjacent to the reactive carbonyl center contributed the enantioface discrimination for the high enantioselectivities.     

Search for nu(e) from the sun at Super-Kamiokande-I

We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.     

X-ray absorption fine structure combined with x-ray fluorescence spectrometry. Part 15. Monitoring of vanadium site transformations on titania and in mesoporous titania by selective detection of the vanadium K alpha1 fluorescence

X-ray absorption fine structure combined with X-ray fluorescence spectrometry was applied to various V+TiO2 hybrid samples. Emitted V K alpha1 fluorescence from the sample was selectively counted by using a high-energy-resolution (0.4 eV) spectrometer equipped with a Ge(331) crystal. Two advantages of this method, extremely high signal/background ratio and the compatibility of measurements in the atmosphere of reaction gas (in situ study in relation to heterogeneous catalysis), were effective at the V K-edge. Structure transformation of the V sites was spectroscopically followed for the V/TiO2 catalyst. The monooxo tetrahedral vanadate site was demonstrated to exist at 473 K. It transformed into dispersed species of 5-fold coordination in ambient air and further into polymeric VO(x) species in 0.85 kPa of water at 290 K. In the presence of 3.2 kPa of 2-propanol, dissociative adsorption of 2-propanol on the dispersed V species was strongly suggested at 290-473 K. In situ structure changes of V sites on TiO2 were reported by means of XAFS for the first time. The V(V) sites for the V/TiO2 catalysts were essentially identical with those for V supported on mesoporous (high-surface-area) TiO2 and V-TiO2 sample prepared by the sol-gel method. However, predominant V(IV) sites were found for mesoporous V-TiO2. The V(IV) sites substituted on the Ti sites of TiO2. When the molar ratio of V/Ti increased from 1/100 to 1/5.0, major octahedral V sites in the TiO2 matrix looked to transform into tetrahedral ones.     

Heterosupramolecular photocatalysis: oxidation of organic compounds in nanospaces between surfactant bilayers formed on TiO2

A heterosupramolecular photocatalyst consisting of TiO2 and a cationic surfactant bilayer formed on the surface has achieved a very high level of activity in the oxidation of 2-naphthol through the cooperation of the inorganic and organic components.