Enzymatic synthesis and chemical recycling of poly(carbonate-urethane)

Novel enzymatically recyclable poly(carbonate-urethane) consisting of a diurethane moiety as a hard segment and a carbonate linkage as an enzymatically cleavable unit was prepared by the polycondensation of biodegradable diurethanediol and diethyl carbonate using lipase. The produced poly(carbonate-urethane) was readily transformed by lipase into the corresponding cyclic oligomers which were more easily repolymerized by lipase to produce a higher molecular weight poly(carbonate-urethane) than that of the parent poly(carbonate-urethane).     

Glycosides of Atractylodes ovata

A new coumarin glycoside and a new glycoside of an acetylene derivative were isolated from the water-soluble portion of the methanolic extract of Atractylodes ovata rhizome together with eight known compounds. Their structures were characterized as scopoletin beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside and (2E)-2-decene-4,6-diyne-1,8-diol 8-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, respectively, based on chemical and spectroscopic investigations. A comparison of the polar constituents among Atractylodes japonica, Atractylodes lancea, and A. ovata is led to the conclusion that A. ovata is distinguishable from A. lancea and A. japonica, as also shown by phylogenetic analysis.     

FT-IR-ATR observation of SiOH and SiH in the oxide layer on an Si wafer

FT-IR-ATR (Fourier transform infrared attenuated total reflectance) technique was used to measure the SiOH and SiH contents in the thermal oxide films grown on Si wafers. It was found that the SiOH groups in the bulk could be eliminated by low temperature annealing, whereas SiOH at the Si/SiO₂ interface could only be removed by high temperature annealing. It was also found that gamma ray irradiation generated SiOH and SiH in the thin oxide film.     

Entanglement cost of implementing controlled-unitary operations

We investigate the minimum entanglement cost of the deterministic implementation of two-qubit controlled-unitary operations using local operations and classical communication (LOCC). We show that any such operation can be implemented by a three-turn LOCC protocol, which requires at least 1 ebit of entanglement when the resource is given by a bipartite entangled state with Schmidt number 2. Our result implies that there is a gap between the minimum entanglement cost and the entangling power of controlled-unitary operations. This gap arises due to the requirement of implementing the operations while oblivious to the identity of the inputs.     

Synthesis of a phloroacetophenon[4]arene consisting of four isomers via the one-pot,acid-catalysed condensation of phloroacetophenone with benzaldehyde

A phloroacetophenon[4]arene (3) consisting of four isomers was synthesised for the first time via the condensation of phloroacetophenone and benzaldehyde in a one-pot reaction with refluxing toluene in the presence of catalytic amounts of TsOH·H₂O for a maximum yield of 64%. The conformational elucidation of four isomers (3a–d) by ¹H NMR spectroscopy and X-ray crystal structure analysis showed them to be cone, partial cone, 1,3-alternate and 1,2-alternate types of conformations, respectively.     

Highly ordered chevron-shaped arrays of continuous copper nano-dot lines formed by electroless deposition on hydrogen-terminated Si(111) surfaces

We have succeeded in forming highly ordered chevron-shaped arrays of continuous copper nano-dot lines by electroless deposition on hydrogen-terminated Si(111) (H-Si(111)) surfaces. Detailed investigations have shown that tiny Cu clusters are preferentially formed at step edges when the electroless deposition is carried out in a deoxygenated neutral aqueous solution of a low Cu2+ concentration (less than 10 microM) with pH approximately = 7. This finding was combined with highly ordered step-edge lines on H-Si(111) prepared by the previously reported method of Teflon scratching and NH4F etching, which has led to the above success. The present result indicates that designed ordered metal nanowires can be produced by the electroless deposition method, using H-Si(111) surfaces with well-regulated step lines as a substrate.     

Enhanced performance of photorefractive poly(N‐vinyl carbazole) composites

We present the enhanced photorefractive performance of high molecular weight poly(N‐vinyl carbazole) (PVCz)‐based composites. Higher diffraction efficiency with faster speed of grating build‐up was obtained by optimizing the composition of the PVCz composites. At relatively low applied electric field of E = 45 V μm^?1, diffraction efficiency of 26% for p‐polarized probe beam and corresponding that of 5.1% for s‐polarized probe beam were measured with faster grating build‐up speed of 48.3 s^?1 for the composite with 2,4,7‐trinitrofluorenone (TNF) as a sensitizer. Fastest speed of grating build‐up of 100 s^?1 and large optical gain up to 110 cm^?1 were measured at E = 80 V μm^?1 for the composite with fullerene derivative of PCBM as a sensitizer. These improved performances are due to a large orientational enhancement effect with faster response speed in addition to Pockels effect for the samples with appropriate glass transition temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Reactions of 2-phospholene 1-oxides with bromine in some media: Facile preparation of bromohydrin derivatives of 2-phospholenes

Reactions of 1-phenyl- and 1-methoxy-2-phospholene 1-oxides with bromine in aqueous organic solvents or in a protic medium, such as methanol, easily afforded the corresponding 2-bromo-3-hydroxy- or 2-bromo-3-methoxyphospholane 1-oxide derivatives. The reaction mechanism was postulated based on the stereochemistry of the products.     

Polymerization of an azastyrene derivative, 1. 1,6-addition polymerization of 2,6-diisopropyl-N-methyleneaniline

The polymerizability of an azastyrene derivative, 2,6-diisopropyl-N-methyleneaniline (DiPMAn), was studied. Although DiPMAn could not be polymerized by radical and anionic initiators, it was polymerized with cationic initiators, such as trifluoroacetic acid (TFA), TiCl₄-TFA, and SnCl₄-TFA. The polymer is formed by 1,6-addition with electrophilic substitution of an activated monomer in para-position of the aromatic ring.