Electrochemical investigation on MEH-PPV/C60 nanocomposite Langmuir–Schaefer films

Ultrathin films of MEH-PPV/C₆₀ nanocomposite with various C₆₀ content were fabricated onto ITO-coated glasses by means of Langmuir–Schaefer method. The cyclic voltammetric investigation on these ultrathin films suggested that these nanocomposites show distinct electrochemical behaviors at various composition ratios.     

EFFECT OF SOLVENT ON THE COPOLYMERIZATION OF 2,2,6,6-TETRAMETHYL 4-PIPERIDINYL METHACRYLATE WITH STYRENE

The radical copolymerizations of 2,2,6, 6-tetramethyl 4-piperidinyl methacrylate (TMPM) with styrene in various solvents have been studied. The monomer reactivity ratios r_1 and r_2 were determined. It is observed that in all of these reaction systems, there are appreciable solvent effects on both r_1 and r_2, which can be correlated to the difference in chemical shifts of olefinic protons of TMPM. And the variance of the copolymer microstructure in various media was discussed.     

Solvothermal preparation of iron phosphonate cages

Three new iron(Ⅲ) phosphonate cage-like complexes with [Fe 4 ], [Fe 9 ] and [Fe 14 ] cores have been synthesized by solvothermal reaction with various starting materials. Magnetic studies show overall antiferromagnetic interaction presented in these cages.     

Recent Advances in the Preparation and Applications of Organo‐functionalized Porous Materials

Organo‐functionalized materials with porous structure offer unique adsorption, catalytic and sensing properties. These unique properties make them available for various applications, including catalysis, CO₂ capture and utilization, and drug delivery. The properties and the performance of these unique materials can be altered with suitable modifications on their surface. In this review, we summarize the recent advances in the preparation and applications of organo‐functionalized porous materials with different structures. Initially, a brief historical overview of functionalized porous materials is presented, and the subsequent sections discuss the recent developments and applications of various functional porous materials. In particular, the focus is given on the various methods used for the preparation of organo‐functionalized materials and their important roles in the heterogenization of homogeneous catalysts. A special emphasis is also given on the applications of these functionalized porous materials for catalysis, CO₂ capture and drug delivery.     

Shape effect of diamagnetic susceptibility of a hydrogenic donor in a nano structured semiconductor systems

The diamagnetic susceptibility of a hydrogenic donor in GaAs/ Al_xGa_1-xAs semiconductor nanostructured systems like Quantum Well Wire and Quantum Dot has been computed for various cross-sectional geometries of these systems for various width of the confining potential in the effective mass approximation using variational method. The non parabolicity of the conduction band has also been included. This calculation may throw some light on the effect of geometries on the semiconductor–metal transition in these systems.     

Development of TiO<Subscript>2</Subscript> photocatalysts suitable for practical use and their applications in environmental cleanup

Recently, environmental disruption is proceeding on a global scale through the consumption of huge amounts of fossil fuels and the emission of various chemical substances. However, these substances resist bio-treatment. TiO₂ generates electrons and holes by irradiation with light. Most organic micro-pollutants, including dioxins, are decomposed into carbon dioxide and water by the effect of the holes with high oxidative potential. By using such a photocatalytic reaction, various applications are feasible for environmental cleanup. In general, TiO₂ powder has been utilized as photocatalyst, although TiO₂ powder photocatalyst has several disadvantages: (1) it is difficult to handle, (2) photocatalytic reaction is slow and it takes a lot of time for treatment and (3) it is difficult to apply to plastics and textiles, because the photocatalyst decomposes them. We have developed a photocatalyst suitable for practical use and have developed high-activity photocatalysts such as TiO₂ photocatalytic transparent film, photocatalytic silica-gel, apatite-coated TiO₂ photocatalyst usable for plastics and textiles, photocatalytic paper, photocatalytic blue charcoal and photocatalytic oxygen scavenger. The application of these high-activity photocatalysts has been studied in deodorization, anti-bacterial, self-cleaning, anti-stain, water treatment, air purification such as photocatalytic decomposition of dioxins and VOC, and NO _x removal. Now various photocatalytic articles using these new photocatalyst materials are on the market in Japan. Photocatalytic technology can create many valuable products for environmental use all over the world.     

Electron donor properties and catalytic activity of manganese ferrospinels

The electron donating properties of manganese ferrospinels of various compositions (MnFe₂O₄, Mn_1.2Fe_1.8O₄, Mn₂FeO₄ and Mn_2.5Fe_0.5O₄) were studied from the adsorption of electron acceptors of various electron affinity values from acetonitrile as solvent. The limit of electron transfer from the oxide surface is from 1.77 to 2.40 eV in terms of the electron affinity of the electron acceptor. The data have been correlated with the catalytic activity of these oxides towards autoxidation of sulfites. Both weak and strong electron donor sites catalyze the reaction.     

Absorption UV spectroscopy and electronic structure of ionic and tautomeric forms of hydroxy and methoxy derivatives of cytosine and adenine,and of some 5-substituted analogs of pyrimidines

The individual absorption spectra of various ionic and tautomeric species of some derivatives of nucleic-acid components have been determined by computer handling of the summary spectra of these compounds measured at different pH values. These individual spectra have been decomposed into separate bands represented by log-normal curves and corresponding to different electronic transitions. Using the parameter system calculated earlier for the molecules of the vitamin B₆ family, the calculation of the electronic spectra and electronic structure of various ionic and tautomeric species of the molecules studied have been carried out in the π-electron approximation. These properties have also been calculated by the all-valence electronic method CNDOS . The calculated results correlate well with both approximations and with our experimental spectral data. The localization of the molecular electronic excitation studied on the transition to the S₁ and T₁ states is considered in connection with the reactivity in these states.     

POLYIONIC COMPLEXES DERIVED FROM POLYVINYL ALCOHOL Ⅰ. PREPARATION AND THEIR SOLVATION BEHAVIOR*

Polycations and polyanions of polyvinyl alcohol (PVA) with various substitution degrees were pre-pared by acetalization of PVA with aldehyde derivatives such as p-formylbenzoic acid, glyoxalic acid, p-formyl-benzenesulfonic acid, p-formylpyridine, and p-dimethylaminobenzaldehyde and then neutral-ized or quaternarized with methyl iodide. The corresponding PVA type polyionic complexes wereobtained by mixing the aqueous solutions of these polycations and polyanions. The solvation behaviourof these polyionic complexes were investigated. It was found that the H_2O-DMF-NaSCN solventsystem is superior to the H_2O-DMF-NaBr system for these PVA type polyionic complexes.     

Basicity and catalytic activity of ZrO2?Y2O3 mixed oxides in the oxidation of cyclohexanol

Acidity/basicity of mixed oxides of ZrO₂−Y₂O₃ activated at various temperatures were determined by a titration method using Hammett indicators. The activity of these oxides towards liquid phase oxidation of cyclohexanol are also reported. The activity data parallel the basicity of these oxides.     

Dilute magnetic semiconductor: Magnesium-doped Zn0.9Cd0.1GeAs2

Dilute magnetic semiconductors based on manganese-doped Zn_0.9Cd_0.1GeAs₂ solid solution with various doping levels were synthesized. Their Curie point in 5-T magnetic field was 349 K. Ferromagnetic ordering in these semiconductors was due to MnAs nanoclusters, whose sizes were 3.7–3.8 nm.     

Speciation in strongly acidic metastable solutions of oxotungstate(vi) compounds

The ionic composition of long-lived metastable aqueous solutions of oxo compounds of tungsten(IV) with pH ≤ 1 was studied by spectrophotometry. The nature of some isopolytung-states formed in these solutions in the presence of various inorganic acids (HCl, HClO₄, HNO₃, H₂SO₄, and H₂SeO₄) was established.     

An evaluation on thermokinetic parameters for hydrogen peroxide at various concentrations by DSC

Information about the kinetics and thermal decomposition of hydrogen peroxide (H₂O₂) has been required for safety reasons, due to its broad applications in many chemical industries. To determine the inherent hazards during H₂O₂ manufacturing, transportation, disposal, usage, and so on, this study deliberately selected various H₂O₂ concentrations and analyzed them by differential scanning calorimetry (DSC). In addition, thermokinetic parameters were not only established for each of these reactions, but also aimed at comprehensive, kinetic models with various tests conducted at different heating rates. To build up a comprehensive kinetic model, various tests were conducted by heating rates of 1, 2, 4, 10°C min^–1, respectively. According to dynamic DSC tests, the experimental curves show that H₂O₂ decomposition has one exothermic peak and may start to decompose under 47–81°C. The total heat of decomposition is about 192–1079 J g^–1. Not only can these results prevent accidents caused by H₂O₂ during storage and transportation, but also assess its inherent hazards and thereby design procedures for emergency response while runaway reactions occurring.     

Multi-arm ionic liquid crystals formed by cholesteric mesophase and pyridinium groups

ABSTRACT

A series of novel star-shaped ionic liquid crystals (ILCs) compounds with various counterions (derived from HBF₄, HPF₆, CF₃COOH, d-MH-SO₃H, H₃PO₄, p-Toluenesulfonic acid) were designed and synthesised starting from precursors of pyridines and liquid crystalline monomer cholesteryl 4-bromobutanoate. Inducing various counterions by use of ionic self-assembly due to electrostatic attraction of various ion clusters was one of the most essential factors for intermolecular separation. The chemical structures, liquid crystalline properties, self-assembly behaviour and ionic conductivity of these compounds were researched during multiple experimental techniques. The star-shaped ILCs showed a smectic A (SmA) mesophase. The d-spacing of star-shaped ILCs increased slightly due to the increase volume of anion. The clearing temperatures of the pyridinium salts suggested that the effect of the stabilisation on the SmA structures was in the order H₂PO₄^?>BF₄^?>T_S^?>D-MH-SO₃^?>CF₃COO^?>PF₆^?. All these star-shaped ILCs displayed ionic conductivity in mesophase. It was noted that the conductivity (σ) increased with the increase of the anion size and temperature.     

Molecular structure of hexatomic heteronuclear (AlFe) metal clusters as determined by the DFT quantum-chemical calculation

Geometric parameters of molecular structures of hexatomic heteronuclear (AlFe) clusters with various number of aluminum atoms (Al₂Fe₄ and Al₃Fe₃) were calculated using the density functional hybrid method in the OPBE/TZVP approximation. It was found that the first of these clusters is able to exist in nine and the second in twenty structural modifications substantially differing from each other in their stability and geometric parameters. The values of bond lengths, planar and dihedral (torsion) angles for some of these modifications are given.     

The mechanism of photocatalytic reaction over Pt/TiO2: Production of H2 and aldehyde from gaseous alcohol and water

Two types of reaction mechanism were found to proceed in the photocatalytic reaction between various alcohols and water over Pt/TiO₂: the reaction of physisorbed alcohol with a hole and with the ?O11 produced by the hole from H₂O. The selectivity of these reactions depends strongly on the electron donor level of the absorbed alcohol species compared with that of H₂O.     

I2O5: mild and efficient reagents for the oxidation of alcohols in water

The mild and efficient nature of HIO₃ and I₂O₅ as environmentally benign, commercially available, atom efficient, and safe reagents for the oxidation of alcohols has been demonstrated. Additionally, these oxidants are highly chemoselective, and effect smooth room temperature oxidation of various electron-rich alcohols with catalytic amounts of KBr in water.     

Syntheses and reactions of triethylgermyllithium,-sodium, -potassium, -rubidium and -caesium in weak solvating solvents

Germylmetallic compounds, Et₃GeM, where M = Li, Na, K, Rb and Cs, have been prepared in high yield in n-hexane or benzene by the reaction of bis(triethylgermyl)mercury with the appropriate alkali metal. Reactions of these compounds with trimethylchlorosilane afforded the coupled product Et₃GeSiMe₃. The interaction of Et₃GeM with benzophenone, acetophenone and phenylacetylene has also been examined. The course of these reactions (i.e. the composition and the yields of the various products) is strongly dependent on the solvating abitity of the solvent and the nature of the alkali metal M.     

Reactions of recoil38Cl atoms with CCl4 and C6H5Cl: Effect of high electron density scavengers

Reactions of recoil³⁸Cl atoms with CCl₄ and C₆H₅Cl have been studied in presence of various high electron density scavengers. Relative reactivities of recoil³⁸Cl towards the two components of these mixtures are determined using the model proposed by Urch.     

Lithium bis-catechol borate as an effective reductive quencher in photoredox catalysis

The use of lithium bis-catechol borate (LiB(cat)₂) as a reductive quencher for the photoredox mediated intermolecular C–H functionalization of various heteroaromatics with bromopyrroloindolines is described. LiB(cat)₂ offers a financial benefit over state-of-the-art quenchers currently in use while eliminating the side reactions that typically plague these couplings. The advantage of this methodology is highlighted by the synthesis of C3–C2’ (?) gliocladin C. Furthermore, additional examples of reactivity with various bromopyrroloindolines sets the stage for expedient routes towards other pharmaceutically active hexahydropyrroloindoline alkaloids and their analogues.