Preparation of Porous Titania Film by Modified Sol-Gel Method and its Application to Photocatalyst

Sol-Gel derived mesoporous titania films with controlled pore sizes were prepared by surfactant templating. The coating sol was obtained by hydrolysis of Ti(OC₄H₉)₄ in ethanol/HCl solution. The gel films, prepared by spin coating on glass substrate, were dried after immersion in surfactant solutions under an atmospheric pressure. The porous films of anatase with columnar and rectangular structure were obtained after annealing at 500°C. The annealed films are transparent and 80–140 nm in thickness. Refractive indices of the films with surfactant immersion were 10–20% lower than those of the films without immersion. The spacing between the columns or rectangular grains and the grain shape were found to depend on the surfactant species. The pohoto-catalytic activity of the films for the oxidation of NO _x was improved by the surfactant modification.     

Selective Chemical Modification to the Higher-Order Structures of Nucleic Acids

DNA and RNA can adopt a variety of stable higher-order structural motifs, including G-quadruplex (G4 s), mismatches, and bulges. Many of these secondary structures are closely related to the regulation of gene expression. Therefore, the higher-order structure of nucleic acids is one of the candidate therapeutic targets, and the development of binding molecules targeting the higher-order structure of nucleic acids has been pursued vigorously. Furthermore, as one of the methodologies for detecting the higher-order structures of these nucleic acids, developing techniques for the selective chemical modification of the higher-order structures of nucleic acids is also underway. In this personal account, we focus on the following higher-order structures of nucleic acids, double-stranded DNA containing the abasic site, T−T/U−U mismatch structure, and G-quadruplex structure, and describe the development of molecules that bind to and chemically modify these structures.     

Preparation and electrochemical and optical properties of unsymmetrically substituted phthalocyanines with one or two trithiole rings and related symmetric derivatives

4,5-Bis(benzylthio)-3,6-diethylphthalonitrile (1) was mixed with 4 -t-butylphthalonitrile and then treated with lithium alkoxide in n-hexanol to produce the corresponding unsymmetrically substituted phthalocyanines (2) and (3) with two or four benzylthio groups, respectively. Treatment of phthalocyanine (2) with nickel(II) acetate yielded the corresponding metal complex 2-Ni. Two benzyl groups of 2 and 2-Ni were removed with lithium/THF/ammonia at -78 degrees C under argon, and the dithiolate anions generated were then reacted with elemental sulfur to give monotrithiolophthalocyanines (5) and (5-Ni). A similar treatment of 3 produced bistrithiolophthalocyanine (6). Tetrakistrithiolophthalocyanine (7-Ni) was prepared by complexation of phthalocyanine (4) with nickel(II) acetate, followed by a Birch reduction of the resulting nickel(II) complex (4-Ni), and then sulfurization and cyclization of the octathiolate anions that were generated. The structures of the phthalocyanines were determined by (1)H NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The optical and electrochemical properties of the phthalocyanines were examined by UV-vis absorption spectroscopy and cyclic voltammetry. Treatment of 5, 5-Ni, 6, 7, and 7-Ni with trifluoroacetic acid in chloroform generated positively charged species, which were characterized by UV-vis and/or NMR spectroscopy.     

Phase separations in liquid crystal-colloid mixtures

We present a mean-field theory to describe phase separations in mixtures of a nematic liquid crystal and a colloidal particle. The theory takes into account an orientational ordering of liquid crystals and a crystalline ordering of colloidal particles. We calculate phase diagrams on the temperature-concentration plane, depending on interactions between a liquid crystal and a colloidal surface and a coupling between nematic and crystalline ordering. We find various phase separation processes, such as a nematic-crystal phase separation and nematic-isotropic-crystal triple point. Inside binodal curves, we find new unstable and metastable regions which are important in phase ordering dynamics. We also find a stable nematic-crystalline (NC) phase, where colloidal particles dispersed in a nematic phase can form a crystalline structure. The coexistence between two NC phases with different concentrations can be appear though the coupling between nematic and crystalline ordering.     

An efficient synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines using zinc chloride/triethylamine reagent system

The one‐pot synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines is described. The reactions of 2‐benzamido‐4,5‐dihydro‐3‐furan(and ‐3‐thiophene)carbonitriles 1a‐d and 2a‐c with ethanol and/or methanol in the presence of zinc chloride and triethylamine gave the corresponding 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines 3a‐d , 4a‐d , 5a‐c and 6a‐c .     

One-pot metal-free syntheses of acetophenones from styrenes through aerobic photo-oxidation and deiodination with iodine

A one-pot synthetic protocol of acetophenones from styrenes with molecular oxygen, visible light, and molecular iodine is reported. This procedure involves aerobic photo-oxidation and deiodination in one pot and provides the first report of metal-free direct syntheses of acetophenones from styrenes.     

Anaerobic biodegradation tests of poly(lactic acid) and polycaprolactone using new evaluation system for methane fermentation in anaerobic sludge

The anaerobic biodegradation tests of polycaprolactone (PCL) and poly(lactic acid) (PLA) powders were done at thermophilic temperature (55 °C) under aquatic conditions (total solid concentrations of the used sludge were 1.73% (undiluted sludge) and 0.86% (diluted sludge)) using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. The biodegradation of PCL powder (10 g, 125–250 μm) in the diluted sludge stopped in about 47 days when the biodegradability reached 92%. The biodegradability of PLA powder (10 g, 125–250 μm) in undiluted sludge was 91% at about 75 days. The biodegradability of PLA powder (10 g, 125–250 μm) in diluted sludge was 79% at about 100 days. The biodegradability of PLA powder (5 g, 125–250 μm) in diluted sludge was 80% at about 85 days. It was found that the PCL and PLA powders were quite degraded using the new evaluation method. In addition, the smaller particle size PCL powder was biodegraded faster.     

Spin Hall effect in Sr2RuO4 and transition metals (Nb,Ta)

We study the intrinsic spin Hall conductivity (SHC) and the d-orbital Hall conductivity (OHC) in metallic d-electron systems based on the multiorbital tight-binding model. The obtained Hall conductivities are much larger than that in p-type semiconductors. The origin of these huge Hall effects is the “effective Aharonov-Bohm phase” induced by the signs of inter-orbital hopping integrals as well as atomic spin-orbit interaction. Huge SHC and OHC due to this mechanism is ubiquitous in multiorbital transition metals.     

Acoustic emission due to nucleation of a microcrack in the proximity of a macrocrack

Acoustic emission generated by the nucleation of a microcrack in the proximity of a macrocrack is discussed in this paper. On the basis of some simple approximations the acoustic emission from a crack-opening event is directly related to its crack-opening volume as a function of time. It is shown that the nucleation of a microcrack in the immediate vicinity of a macrocrack generates additional crack-opening volumes for both the macrocrack and the microcrack, whose signals tend to be much larger than those that would emanate from a nucleating solitary microcrack.