Sunlight-induced efficient and selective photocatalytic benzene oxidation on TiO2-supported gold nanoparticles under CO2 atmosphere

The sunlight-induced photocatalytic oxidation of aqueous benzene on TiO(2)-supported gold nanoparticles was considerably improved when the reaction was conducted under a CO(2) atmosphere. 13% yield and 89% selectivity of phenol was obtained on P25-supported gold nanoparticles under 230 kPa of CO(2).     

Remark on the stability of the large stationary solutions to the Navier–Stokes equations under the general flux condition

Consider stationary weak solutions of the Navier–Stokes equations in a bounded domain in R³${\mathbb{R}}^3$ under the nonhomogeneous boundary condition. We give a new approach for the stability of the stationary flow in the L²$L^2$-framework. Furthermore, we give some examples of stable solutions which may be large in L³(Ω)$L^3\left(\Omega \right)$ or W^1,3/2(Ω)$W^{1,3/2}\left(\Omega \right)$.     

Determination of binding constants of various alkali metal cations with p-sulfonatocalix[8]arene by using inclusion equilibrium with thionine dye

The binding constants of various alkali metal cations with water-soluble p-sulfonatocalix[8]arene (Calix-S8) were determined spectrophotometrically by using the inclusion equilibrium of thionine (Th) dye as a chemical indicator. Depending on the kind of alkali metal cations, the inclusion constants of Calix-S8 for Th decrease steeply with an increase in salt concentrations. Alkali metal cations compete with the organic guest Th in the Calix-S8 inclusion. Based on a competitive binding experiment, the binding constants of alkali metal cations with Calix-S8 were evaluated to be 17, 60, and 11 dm⁶ mol^?2 for Na⁺, K⁺, and Cs⁺, respectively. We have demonstrated an absorption-based method of evaluating the binding constants of spectroscopically inert metal cations with Calix-S8 and shown the effects of salts on the molecular recognition of Calix-S8.     

Synthesis of Block Copolyamides by End-Reactive Oligomers

Block copolyamides having poly(propylene oxide) units in main chains were prepared by interfacial polyconden-sation using hydroxyl-terminated poly(propylene oxide), acid chloride and diamine. Block copolyamides having poly(styrene) segments were also prepared by the same technique by using endcaped poly(styrene) with carboxyl or amine end groups. They were characterized by spectroscopic, thermal and X-ray analyses.

Platlet adhersion behaviors were evaluated on the surface of these block copolyamides and it was found that the platelet adhersion and aggregation were greatly influenced by the domain size as well as the distribution of the block units in the block polyamides. Bio-compatibilities of these block po-lyamides were discussed in respect of microphase-separated domain structures.     

New Photosensitive High Temperature Polymers for Electronic Applications

A new photosensitive high temperature polymer stable up to 500%deg;C with high photosensitivity and high resolution has been developed. The trend toward a high degree of integration in solid-state technology requires the use of new high temperature photosensitive insulating materials. Toray's Photoneece system provides such versatile polyimide pattern-generation techniques, containing a unique photosensitive polyimide precursor which can be spun or coated on the substrate. The resultant relief of photosensitive polyimide precursor, after exposure to UV light with a mask, development, and cure processing, is transformed into a cyclized aromatic polyimide. The new system has higher photosensitivity and resolution and eliminates three steps in the conventional pattern-making process for integrated circuits, resulting in a significant cost reduction. The characterization of pattern generation, the conversion to polyimide patterns, and the properties of both Photoneece and the patterns are discussed.     

Rapid Determination of Polar and Non-Polar Pesticides in Human Serum,Using Mixed-Mode C-C18 Monolithic Spin Column Extraction and LC–MS/MS

Organophosphates and carbamates are pesticides whose acute toxicities are caused by inhibition of acetylcholinesterase. A liquid chromatography–mass spectrometry/mass spectrometry method was developed and validated for the quantification of 16 organophosphate and carbamate insecticides in human serum. Nonpolar and polar pesticides were simultaneously extracted from serum samples using a simple and fast monolithic spin column procedure using mixed-mode C-C₁₈ cartridges. Recovery was achieved in the range 11.9–99.2 %. Chromatography was carried out on an InertSustain^® C₁₈ HP 3 μm analytical column with gradient elution. Mass spectrometric analysis was performed using an Agilent 6410 Triple Quad Tandem mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The assay was validated over a large concentration range and the limits of detection for all compounds ranged from 0.1 to 50 ng mL⁻¹. The precision for both intra- and inter-day determination of all analytes was found to be acceptable (< 12.9 %) and no significant matrix effect was observed. The developed method was effectively applied to clinical samples from patients presenting at hospital with symptoms of acute intentional organophosphate or carbamate poisoning, demonstrating its applicability to diagnostic applications.

     

Unique inclusion behaviour of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetraaminothiacalix[4]-arene towards small organic molecules

Tetraaminothiacalixarene 3, bearing four amino groups instead of the hydroxy groups of p-tert-butylthiacalix[4]arene 2, exhibits inclusion properties different from those of compound 2 towards small organic molecules upon crystallisation from neat solvents or guest solutions. X-ray crystallographic analyses reveal that nitromethane and acetonitrile are included into the cone-shaped cavity of compound 3, as is often seen in inclusion crystals of compound 2, whereas dichloromethane occupies a space between two distal benzene rings of compound 3, adopting a 1,3-alternate conformation. Acetic acid, which forms a dimer, fills a pore surrounded by four host molecules with a pinched cone conformation. Furthermore, guest-free crystals of compound 3 with a 1,3-alternate conformation absorb acetonitrile to give inclusion crystals with the same crystal structure as that obtained by the crystallisation. Thus, compound 3 flexibly changes its conformation according to the structures of guest compounds.     

Temperature dependence of multilayering at the free surface of ionic liquids probed by X-ray reflectivity measurements

The effect of the temperature on the surface layering of ionic liquids has been studied for two ionic liquids, trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide([TOMA(+)][C(4)C(4)N(-)]) and trihexyltetradecylphosphonium bis(nonafluorobutanesulfonyl)amide ([THTDP(+)][C(4)C(4)N(-)]), using X-ray reflectivity measurements at 285, 300, and 315 K. Both [TOMA(+)][C(4)C(4)N(-)] and [THTDP(+)][C(4)C(4)N(-)] develop multilayers at the surface. The structure of the multilayers at the [TOMA(+)][C(4)C(4)N(-)] surface shows little temperature-dependent change, whereas that at the [THTDP(+)][C(4)C(4)N(-)] surface clearly becomes diffused with increasing temperature. The different temperature dependence seems to be related to the difference in the recently reported ultraslow dynamics of the interfacial structure of [TOMA(+)][C(4)C(4)N(-)] and [THTDP(+)][C(4)C(4)N(-)] at the ionic liquid|water interface.     

Isolation and characterization of atropisomers of seven-membered-ring benzolactams

The atropisomeric properties of seven-membered-ring benzolactams (7a-c and 8a) [1,5-benzodiazepin-2-one (a), 1,5-benzothiazepin-4-one (b), and 1-benzazepin-2-one (c)] were examined. The atropisomers were isolated as the diastereomers with an (S)-phenethylamide moiety, which were characterized by X-ray crystallography, and the barriers to their interconversion were clarified.     

4-Carbomethoxybenzaldehyde as a highly sensitive pre-column fluorescence derivatization reagent for 9,10-phenanthrenequinone

9,10-Phenanthrenequinone (PQ) is harmful environmental pollutant that is detected in airborne particulates. The measurement of PQ in the air should be necessary to evaluate the potential adverse effects of PQ on human health. We have recently developed a determination method for PQ based on the fluorescence derivatization of PQ using benzaldehyde and ammonium acetate as a reagent. In this study, in order to obtain more sensitive and selective fluorescence derivatization reaction, we measured the fluorescence of the reaction mixture of PQ with 21 kinds of aromatic aldehydes in the presence of ammonium acetate. Among the tested aldehydes, 4-carbomethoxybenzaldehyde was found to be the best reagent in regard to fluorescence intensity and emission wavelength maximum. Based on the fluorescence derivatization with 4-carbomethoxybenzaldehyde, a highly sensitive chromatographic method was developed for the determination of PQ with the detection limit (S/N=3) of 1.2 fmol/injection.