Direct photo-oxidation of benzene to phenol over Ti/Si binary oxide prepared by sol-gel method

Titanium-silicon (Ti/Si) binary oxides having a varying Ti content were prepared using the sol-gel method and used as photocatalysts. The photo-oxidation of benzene to phenol was carried out using Ti/Si binary oxide catalysts in the presence of benzene, water and gaseous oxygen. The amounts of benzene used hardly affected the phenol yield. On the other hand, the addition of sulfuric acid into reaction solution led to the improvement of phenol formation. The H₂O₂ formation rate seemed to be related to the phenol yeilds. The photocatalytic reactivity of Ti/Si binary oxide having different TiO₂ contents was investigated and it was found to be dramatically enhanced in the range of lower TiO₂ contents. XANES, ESR and XRD spectroscopic investigations of these Ti/Si binary oxide catalysts indicated that Ti species were highly dispersed in SiO₂ matrices and existed in a tetrahedral coordination. The photo-irradiation of catalysts having tetrahedral Ti species seemed to effectively lead to the formation of H₂O₂ as an intermediate.     

Photosensitive poly(vinyl alcohol) bearing N-(1-pyridinio)benzamidate groups

Poly(vinyl alcohol) (PVA) bearing N-(1-pyridinio)benzamidate (PB) was synthesized through acetalization of PVA and 4-dimethoxymethyl-N-(1-pyridinio)benzamidate (DMPB) in water. The PB groups in PVA–PB had almost the same proportion of DMPB to the starting PVA. The UV spectrum of PVA–PB shows an absorption band of pyridinium ylide as a shoulder around 300 nm in water, and as a maximum at 315 nm in a film on a quartz plate. These absorption bands decreased on irradiation at 313 nm. The photoreaction of the PVA–PB film proceeds much faster than that of PVA–PB in water. The solution, of PVA-bearing high-PB content, became slightly turbid during irradiation. After irradiation the film became insoluble in water, and the soluble fraction of polymer (P? = 1700) was 3% at a PB content of 1 mol% and less than 1% at that of more than 2 mol%. This polymer can be applied as a water-soluble negative photoresist.     

A chiral π-stacked vinyl polymer emitting white circularly polarized light

An optically active, π-stacked poly[2,7-bis(4-tert-butylphenyl)dibenzofulvene] having a preferred-handed helical conformation was synthesized by anionic polymerization. A thin film sample of the polymer exhibited broad-band white circularly polarized light (CPL) emission on photo excitation.     

Application of Benzoyl-substituted Hemithioindigo as a Molecular Switch in Porphyrin-Quinone Recognition

The benzoyl-substituted hemithioindigo 1 with Z-configuration was obtained as the sole product from the reaction of 7-ethylbenzo[b]thiophen-3(2H)-one with phenylglyoxal. Irradiation of 1 produced the [2+4] cycloadduct 2, instead of the usual Z ? E isomerization product. The cycloadduct 2 is completely dissociated back to 1 on heating; the interconversion between 1 and 2 shows good repeatability. This reversible property is applied to the molecular switch in the hydrogen-bonded quinone recognition of the 5,15-cis-bis(ureidophenyl)porphyrin 3. resulting in the release of     

An Efficient Synthesis of Sulfo Lewis X Analog Containing 1-Deoxynojirimycin 1

Abstract

Sulfo Lewis^x analog containing 1-deoxynojirimycin (13) has been efficiently synthesized. Glycosidation of ethyl 2,3,4-tri-O-benzyl-1-thio-β-D-fucopyranoside (5) with O-2,6-di-O-benzoyl-3,4-isopropylidene-β-D-galactopyranosyl)-(1→4)-2,6-di-O-benzoyl-N-benzyloxycarbonyl-1,5-dideoxy-1,5-imino-D-glucitol (4), prepared from O-β-D-galactopyranosyl-(1→4)-1,5-dideoxy-1,5-imino-D-glucitol (1) via 3 steps, and subsequent acid hydrolysis of the isopropylidene group gave the desired trisaccharide diol derivative (7) in good yield. Compound 7 was easily converted into 3′-O-sulfo Lewis^x analog (13) via 6 steps in high yield.

     

Accurate calculation of core-electron binding energies: multireference perturbation treatment

Multireference perturbation theory (MRPT) with multiconfigurational self-consistent field (MCSCF) reference functions is applied to the calculations of core-electron binding energies (CEBEs) of atoms and molecules. Orbital relaxations in a core-ionized state and electron correlation are both taken into account in a conventional MCSCF-MRPT procedure. In the MCSCF calculation, the target core ionized state is directly optimized as an excited state and this treatment can completely prevent a variational collapse. Multireference Moller-Plesset perturbation theory and multiconfigurational self-consistent field reference quasidegenerated perturbation theory were used to treat electron correlation. The present method quite accurately reproduced the 1s CEBEs of CH4, NH3, H2O, and FH; the average deviation from the experimental data is 0.11 eV using Ahlrichs' VTZ basis set. The C 1s and O 1s CEBEs of formic acid and acetic acid were calculated and the results are consistent with the bonding characters of the atoms in these molecules. The present procedure can also be applied to CEBEs of higher angular momentum orbitals by including spin-orbit coupling. The calculated CEBEs of Ar 2p, HCl 2p, Kr 3d, and HBr 3d are in reasonable agreement with the available experimental values. In the calculation of the 3d CEBEs, a relativistic correction significantly improves the agreements. The effect of polarization functions is also discussed.     

Prediction of granule physical property by a novel compression energy of wet powder

Wet granulation is a very important process and a reliable evaluation method for formulation study; thus it requires appropriate process control. In this study, a novel and effective method that involves a compression test of wet powder is proposed. Here, the compression energy, which could predict the capability of the wet powder for extrusion granulation as well as the physical properties of the final products, is used as a novel characteristic of wet powder. The compression energy was defined as the energy consumption derived from the compression speed and the transmission loss during the compression test. Lactose monohydrate was mixed with various additives such as hydroxypropylcellulose in the mass ratio of 0-10%. Various amounts of water were fed into the mixtures, which were kneaded in a planetary motion mixer to prepare the kneaded wet powders. The characteristics of these powders were evaluated by the compression energy. The kneaded wet powders were then extruded through an extrusion granulator, the electrical loads of the granulator during the operation were analyzed as the extrusion energy, and the physical properties of extruded granules were investigated. As a result, the granule strength and granule size distribution showed a good correlation with the compression energy. A good correlation was also observed between the compression energy of the kneaded wet powder and the extrusion energy regardless of the different additives and water contents. It was concluded that the compression energy of the wet powder could be used for the formulation study and the process control of wet granulation.     

Nanoscale spherical architectures fabricated by metal coordination of multiple dipyrrin moieties

Phenylethynyl-bridged dipyrrin "dimers" have performed ZnII complexation to give coordination polymers, which provided the fluorescent colloidal spherical objects in solution as well as on the substrate according to the spacer units. Using a mixture of THF and water, unique morphologies, such as bell-shaped and "golf ball"-like architectures, were observed.     

Noise reduction method for molecular interaction energy: application to in silico drug screening and in silico target protein screening

We developed a new method to improve the accuracy of molecular interaction data using a molecular interaction matrix. This method was applied to enhance the database enrichment of in silico drug screening and in silico target protein screening using a protein-compound affinity matrix calculated by a protein-compound docking software. Our assumption was that the protein-compound binding free energy of a compound could be improved by a linear combination of its docking scores with many different proteins. We proposed two approaches to determine the coefficients of the linear combination. The first approach is based on similarity among the proteins, and the second is a machine-learning approach based on the known active compounds. These methods were applied to in silico screening of the active compounds of several target proteins and in silico target protein screening.     

Synthesis and adsorption properties of p-sulfonated calix[4 and 6]arene-intercalated layered double hydroxides

The intercalation of water-soluble p-sulfonated calix[4 and 6]arene (CS4 and CS6) in the interlayer of the Mg-Al and Zn-Al layered double hydroxide (LDH) by the coprecipitation method has been investigated, as well as the adsorption properties of the resulting CS/LDHs for benzyl alcohol (BA) and p-nitrophenol (NP) to prepare new microporous organic-inorganic hybrid adsorbents. The amount and arrangement of CS intercalated was different by the kind of the host metal ions. CS4 cavity axis was perpendicular for the Mg-Al LDH basal layer and parallel for the Zn-Al LDH basal layer, while CS6 cavity axis was perpendicular for both the LDH basal layers. In the BET surface area measurement, the surface area of the Zn-Al/CS4/LDH was four times than that of the Mg-Al/CS4/LDH, expecting that the former has higher adsorption capacity than the latter. In fact, the adsorption ability of the CS/LDHs for BA and NP in aqueous solution was found to be larger in the Zn-Al/CS4/LDH than in the Mg-Al/CS4/LDH. In addition, the adsorption ability of both the LDHs was larger in the CS6/LDHs than in the CS4/LDHs. These results were explained by the difference in the amount and arrangement of CS intercalated in the LDH interlayer space.