Changes in the near-edge X-ray absorption fine structure spectra of long-chain diacetylene derivatives through photopolymerization in Langmuir–Blodgett films

Photopolymerization of cadmium 10,12-pentacosadiynoate (CdDA) in Langmuir–Blodgett (LB) films, with the molecular packing well arranged by moderate preannealing, was investigated with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Greenish films of polydiacetylene with an absorption wavelength of 705 nm were obtained through the photopolymerization of preannealed monomer LB films, and this resulted in an extended π-conjugate system based on the well-ordered monomer in a two-dimensional arrangement. The electronic structures of the polydiacetylenes were found to be correlated to the variation of the molecular arrangements in the films from the changes in the NEXAFS spectra through photopolymerization in the LB films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2329–2336, 2004     

Laser spectroscopy of trapped 7Be and 10Be at a prototype slow RI-beam facility of RIKEN

A next-generation slow radioactive nuclear ion beam facility (SLOWRI) which provides slow, high-purity and small emittance ion beams of all elements is being build as one of the principal facilities at the RIKEN RI-beam factory (RIBF). High energy radioactive ion beams from the projectile fragment separator BigRIPS are thermalized in a large gas catcher cell. The thermalized ions in the gas cell are guided and extracted to a vacuum environment by a combination of dc electric fields and inhomogeneous rf fields (rf carpet ion guide). From there the slow ion beam is delivered via a mass separator and a switchyard to various devices: such as an ion trap, a collinear fast beam apparatus, and a multi-reflection time of flight mass spectrometer. In the R&D works at the present RIKEN facility, an overall efficiency of 5% for a 100A MeV ⁸Li ion beam from the present projectile fragment separator RIPS was achieved and the dependence of the efficiency on the ion beam intensity was investigated. Recently our first spectroscopy experiment at the prototype SLOWI was performed on Be isotopes. Energetic ions of ¹⁰Be and ⁷Be from the RIPS were trapped and laser cooled in a linear rf trap and the specific mass shifts of these isotopes were measured for the first time.     

Characterization of U series nuclides in geological materials by selective leaching method

Geological and geochemical events were elucidated in by using U series nuclides in combination with chemical leaching technique. Two examples were examined: (1) in the apatite-bearing sediment column samples U(VI) is moving, while U(IV) in the samples is almost retained, and (2) the redistribution of U occurred along the column under the monsoon climate. On the other hand, U in the conglomerate sample is divided into 5 categories by the leaching technique, which are related with exchangeable, carbonate, iron oxide, organic/sulfide and silicate components, respectively. Uranium is shown to be abundant in the carbonate and iron rich fractions of conglomerate sediment. Appropriate models are proposed in each case study.     

A study on LH- and FSH-RIA kits by immunoradiometric assay

An evaluation of LH- and FSH-RIA BEAD kits based on IRMA was carried out. The results obtained with the methods characterized by the use of monoclonal antibodies, i.e., one is linked to solid phase, and another is isotopically labeled, were compared with those determined by the Daiichi LH- and FSH-kits. Intra- and inter-assay precision, recovery, linearity, and specificity of both methods were favorable without exceptions. The cross reactivity of the LH kit to 5,000 mIU/ml hCG revealed within the range of less than 3 mIU/ml. Significant correlations were observed between the results derived from conventional Daiichi LH- and FSH-kits. The results from the conventional kits exhibited 30 to 40% of those from the Daiichi kits, considered to be mainly due to the difference in standard calibrations used. Among the individuals within the normal menstrual cycle, the serum LH- and FSH-levels determined by the present kits gave a typical pattern with a peak in the preovulatory phase. On the other hand, the LH- and FSH-values of individuals in normal pregnancy revealed strikingly decreased in comparison with those of non-pregnant women.     

Reaction of phosgene with the tricycle related to the minor base of phenylalanine transfer ribonucleic acids

1-Benzylwye (8) underwent electrophilic substitution at the 7-position in the presence of phosgene and pyridine in tetrahydrofuran (THF) to afford the 1,4-dihydropyridines (11, 10, and 14) together with the carboxylic acid 6 and its methyl ester 2 after short treatment of the reaction mixture with methanol and then with water. When triethylamine was used instead of pyridine, phosgene reacted with triethylamine rather than 8, producing (E)-3-(diethylamino)propenoyl chloride (17) and diethylcarbamoyl chloride (18).     

Cu(I)-catalyzed direct enantioselective cross aldol-type reaction of acetonitrile

Direct catalytic enantioselective cross aldol-type reaction of an acetate surrogate was developed using Cu alkoxide-chiral phosphine complexes as catalysts. Chemoselective activation and deprotonation of the donor substrate (acetonitrile) by the soft metal alkoxide in a strongly donating solvent (HMPA) are key to success in this reaction. Useful chemical yields and promising enantioselectivities are produced using either DTBM-SEGPHOS or a tuned BIPHEP as a chiral ligand. [reaction: see text]     

Sine-wave polarographic determination of zirconium or niobium in aqueous media

The sine-wave polarographic determination of zirconium in aqueous media was investigated using solutions which were 0.55 – 5.5·10^-3M in zirconyl chloride and 1 M in potassium chloride and had been adjusted to pH 2.0 with hydrochloric acid. It was possible to determine zirconium in the concentration range of 0.05 to 0.4 mg per ml. The sine-wave polarographic behavior of zirconium in aqueous solutions in the pH range 2–3 is discussed. The sine-wave polarographic determination of niobium in aqueous media was investigated using concentrated sulfuric acid containing 5 to 0.1 mg of niobium per ml in a supporting electrolyte of citric acid; the determination of niobium was possible down to 0.1 mg of niobium per ml of concentrated sulfuric acid although the D.C. polarographic method was impractical for the determination of less than 0.5 mg of niobium per ml.     

One-pot preparation of chiral beta-amino esters by rhodium-catalyzed three-components coupling reaction

Chiral beta-amino esters are synthesized in one-pot from three components, amines, aldehydes, and ethyl bromoacetate, under the rhodium-catalyzed Reformatsky-type reaction condition, where complete diastereoselection is achieved in the nucleophilic addition step of ethyl bromoacetate to the imines prepared in     

Sine-wave polarographic determination of small amounts of indium in the presence of large amounts of cadmium,lead or tin

The sine-wave polarographic determination of small amounts of indium in the presence of large amounts of cadmium, lead or tin was investigated. The determination of indium in cadmium was possible down to 0.01 % in 1 M potassium iodide at pH 2, the determination of indium in lead was possible down to 0.02 % in 1 M potassium chloride at pH 2, and the determination of indium in tin was possible down to 0.3 % in 1 M hydrochloric acid and down to 0.2 % in 2 M perchloric acid with 0.5 M sodium chloride.     

Formal catalytic asymmetric total synthesis of fostriecin

The common synthetic intermediate of a potent and promising anticancer agent, fostriecin, was synthesized using a unique method that combines four catalytic asymmetric reactions as shown above.