ChemInform Abstract: Facile Synthesis of Glycidates via Oxidation of Acrylates with Aqueous Solution of NaOCl in the Presence of Ammonium Salts.

The green and fast oxidation of acrylates proceeds in the presence of ammonium catalysts with appropriate structures.     

Formation of flat, homogeneous surfaces of organized molecular films of three-armed polymerizable amphiphiles with metal-scavenging properties

Surface complexing (i.e., metal-bridged polymerization in this study) of a three-armed amphiphilic compound with metal-scavenging properties has been investigated using the surface pressure-area (π-A) isotherms of a Langmuir monolayer from the subphase. Inductively coupled plasma mass spectrometry (ICP-MS) was also carried out on eluted solutions from corresponding multilayers of the solid. Furthermore, the molecular arrangement and surface morphology of organized molecular films of the resultant comb polymer were estimated by in-plane and out-of-plane X-ray diffraction (XRD) and by atomic force microscopy. From an analysis of the wide-angle X-ray diffraction of the corresponding monomer in the bulk, the long hydrocarbon chains are observed to pack hexagonally in the solid state. Compared to their monolayer on distilled water as the subphase, a polymerized monolayer on a buffer solution containing Cd(2+) ions is remarkably expanded at 15 °C. From ICP-MS and IR measurements, it is found that this monolayer stoichiometrically contains Cd(2+) ions on the -SH group. It is found by XRD that highly ordered layer structures and regular 2D lattices are constructed in the organized molecular films of the Cd-bridged comb polymer. Furthermore, the surface morphology of Langmuir-Blodgett films fabricated from the monolayers on a buffer solution containing Cd(2+) and Pd(2+) shows flat and smooth domains upon metal scavenging and polymerization.     

Optical rectification effect due to surface plasmon polaritons at normal incidence in a nondiffraction regime

We carried out an experimental and numerical investigation of photoinduced voltage at normal incidence in the nondiffraction regime, which was not predicted to occur by the simple momentum conservation model. We prepared two samples: one having space inversion symmetry and the other without this feature. At normal incidence in the nondiffraction regime, we observed a finite signal only for the asymmetric structure. We found that surface plasmon polaritons (SPPs) are excited by the signal and are attributed to the origin of the voltage. We also evaluated the radiation force of light by using the Maxwell stress tensor and found that pressure of light and not shear force is mainly induced in the structure due to the asymmetric excitation of SPPs.     

A catalytic version of hypervalent aryl-λ3-iodane-induced Hofmann rearrangement of primary carboxamides: iodobenzene as an organocatalyst and m-chloroperbenzoic acid as a terminal oxidant

The first catalytic version of hypervalent aryl-λ(3)-iodane-induced Hofmann rearrangement of primary carboxamides, which probably involves in situ generation of a tetracoordinated bis(aqua)(hydroxy)phenyl-λ(3)-iodane complex as an active oxidant from a catalytic amount of iodobenzene by the reaction with m-chloroperbenzoic acid in the presence of HBF(4) in dichloromethane-water under mild conditions, was developed.     

Photoelectrochemical properties of TiO2 photocatalyst and its applications for environmental purification

In view of the situation that environmental issues become more serious day by day, recent studies on practical applications of TiO₂ photocatalysis for environmental purification are reviewed. Although the fundamental aspects and the mechanisms of TiO₂ photocatalysis have recently become quite well understood, effective photocatalytic environmental purifier, especially water purifier, could not be developed to the stage of real industrial technology. The removal rate of gaseous or aqueous contaminants is influenced by numerous parameters; UV light intensity, substrate concentration, O₂ partial pressure, humidity, substrate type, and so on. Moreover, TiO₂ photocatalyst essentially has a difficulty in decomposition of large amount of contaminants or refractory chemicals. As the solutions of these problems, combination with other processes such as advanced oxidation processes and improvement of the design of photocatalytic environmental purification systems are described. During the past several years, the strategies for effective design of the system are well discussed and evaluated. The reactor design for air- or water-purification can be classified into two main strategies: (1) enlargement of reactive surface area and (2) improvement of mass transfer. Based on these insights, very recent achievements for development of photocatalytic environmental purification system with our contribution in each aspect and future research directions are reviewed.     

Twist decompositions of gluing homeomorphisms of planar Heegaard diagrams of genus two

We will give a very simple algorithm to decompose a gluing homeomorphism of a planar Heegaard diagram of genus two into Dehn twists associated with the canonical base.

     

Non‐Shrinking Networked Materials from the Cross‐Linking Copolymerization of Spiroorthocarbonate with Bifunctional Oxetane

Summary: The cationic ring‐opening copolymerization behavior of SOC1 with BOXT and the properties of the obtained cross‐linked copolymers are described. SOC1 and BOXT are cationically copolymerized under various feed ratios to obtain the corresponding cross‐linked copolymers in 73–96% yields. The volume change during copolymerization could be controlled by the addition of SOC1 to obtain non‐shrinking or volume‐expanding copolymers. The glass transition temperatures (T_g) of the copolymers also decrease linearly with the feed ratio of SOC1, which suggests that the introduction of the flexible poly(SOC1) segment into the rigid BOXT cross‐linked segment relieves the internal stress in the resins that severely degrade their mechanical properties.

Cationic copolymerization of SOC1 and BOXT.     

Experimental system for X-ray magnetic diffraction under extreme conditions

An experimental system for X-ray magnetic diffraction (XMD) under extreme conditions was constructed on the beamline BL39XU at SPring-8. This system aims at studying magnetic properties of ferromagnets through the measurements of magnetic form factors under the conditions of low temperature (5 K), high magnetic field (6 T) and high pressure (10 GPa). This system consists of a superconducting magnet (SCM), a diamond anvil cell (DAC), a two-axis manipulator for the DAC, a five-axis goniometer for the SCM, and an X-ray polarizer with a phase plate. Details of this system are presented. Experimental results on uranium telluride are shown as a performance test with this instrumentation.     

μSR studies of low charge carrier density heavy‐fermion systems

We report on μSR studies in low charge carrier density heavy‐fermion systems with cubic symmetry. Whereas for Ce₃Au₃Sb_4 and for Sm₃Te₄ the μSR data point to the presence of some kind of spin‐glass‐like magnetic states at low temperature, for Yb₄As₃ preliminary μSR studies just show a slight increase of the depolarization rate which indicates a slight slowing down of the Yb‐moment fluctuations. Consequently for this latter system, the large linear term of the specific heat seems indeed to be connected to electronic excitations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Solvation effects on photochemically-induced electron transfer from tris(bipyridyl)ruthenium to methylviologen

Summary The effects of mixed solvent systems and anions on the rate of reaction of the title compounds were investigated. The results were shown to be best interpreted in terms of ion-pair formation and solvation-desolvation effects, in addition to the factors included in the outer-sphere electron transfer rate theory expounded by Marcus.