Deprotonation in anodic methoxylation of fluoroethyl phenyl sulfides using site-isolated heterogeneous bases

On the basis of the concept of site isolation in electrochemical reactions, we have successfully demonstrated acceleration of the deprotonation step in anodic methoxylation of fluoroethyl phenyl sulfides using silica gel supported bases.     

Orientational ordering of crystal domains in ionic liquid based mixtures

By in situ observations using simultaneous X-ray diffraction and the DSC (differential scanning calorimetry) method, the effect of water, methanol, ethanol, and benzene on the crystallization has been observed in an ionic liquid (IL)-rich phase. The IL is a hydrophilic ionic liquid, N, N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF4]. At a small amount of the above additional molecules in the IL, the conventional preferred orientation on the Debye rings was seen by the X-ray diffraction. At 0.9 mol % H2O, twinlike crystal domains develop extraordinary on the microdomains. By the "crystal-growth enhancement effect" at a slight amount of water, a composite domain structure, which consists of the large domain and the weakly orientated microdomains, is formed without internal strains. Above 2.9 mol % H2O, the domain structure, however, disappears completely. It is remarkable that, in a thermal cycling experiment using pure [DEME][BF4], the similar composite domain structure appeared. This is also caused by an uptake of a slight amount of water.     

Nitrogen-directed ortho-selective homocoupling of aromatic compounds catalyzed by ruthenium complexes

A nitrogen-directed regioselective homocoupling reaction of aromatic compounds has been found to be catalyzed by a ruthenium complex in the presence of methallyl acetate as a hydrogen scavenger.     

Platinum-catalyzed regio- and stereoselective arylthiolation of internal alkynes

Unsymmetrical internal alkynes such as ethyl phenylpropiolate (2b) successfully underwent Pt-catalyzed decarbonylative arylthiolation by thioesters. The regio- and stereoselective insertion of 2b into an S-Pt bond was confirmed by reaction with a platinum complex with an S-Pt-Cl framework.     

Self-organized ZnO nanorod with photooxidative cell membrane perforation enables large-scale cell manipulation

Various devices have been developed for verification and application of cellular functions in recent years. In our previous study, we found that local oxidation reactions in the cell membrane could produce submicron sizes of reversible membrane perforations in cells, while more than 80% of treated cells were viable even after perforations; therefore, to date, we have attempted some applications of this mechanism and analyzed their feasibility. In the present study, we developed a rod-shaped device in which the function of membrane perforation is added by utilizing a photosensitizer and, using the device, we have attempted to produce membrane perforations in a large number of cells. Zinc oxide nanorods were synthesized on the basis of the vapor–liquid–solid mechanism and α-terthienyl (photosensitizer) was adsorbed onto gold at the top of the rods to add a membrane perforation function. We studied the effect of the oxidation catalytic ability of the rods on rat PC12 cells after pressing and making the rods’ growth side come into contact with the base plate pressed onto the cells in a culture plate followed by photoexcitation of the photosensitizer for a certain period of time. It was revealed that water-soluble fluorescent marker molecules added extracellularly were taken up by the cells when the rods were applied at a pressure of 70 g/cm², with a light intensity of 0.82 W/cm², and with light irradiation for 30 s, as found in the case of the conventional photochemical cell membrane perforation method targeted at a single cell. These results suggest that cell membrane perforation can be successfully achieved in a large number of cells at a time. Figure Large-scale cell membrane perforation process using self-organized nanorods     

Sensitive light-scattering detection–magnetophoretic acceleration mass analysis of single microparticles in an atmosphere

Optically detected magnetophoretic acceleration mass analysis of an individual micro-particle in an atmosphere has been remarkably improved in sensitivity by using a reflective microscope objective, by which forward scattered light from a particle could be effectively collected. From the light-scattering simulation, the detection limit for the radius of a micro-particle was estimated to be smaller than 0.4 μm, and about 60 times intensity enhancement was observed for a polystyrene particle with a radius of 2.8 μm. For both paramagnetic and diamagnetic micro-particles, the mass magnetic susceptibility and the relaxation time could be determined without knowing any parameters of the particles. From the relaxation time, the mass of a particle was obtained if the radius or the density of the particle was known. For a test sample silica particles were used to adsorb paramagnetic dysprosium(III), the surface concentration of dysprosium(III) on a single particle could be successfully determined by use of this method.     

Synthesis of 3/8-carbonylated chlorophyll derivatives and regiodependent reductivity of their carbonyl substituents

Methyl pyropheophorbide-d possessing a formyl group at the 3-position and its regioisomer having 8-CHO were prepared and their reactivities with a reductant were determined by the ¹H NMR technique: 3-CHO>8-CHO. The regioselective reduction of a synthetic 3,8-diformyl-chlorin also supported the higher reactivity in 3-CHO than in 8-CHO. Regiodependent reduction of the corresponding acetyl-chlorins confirmed that carbonyl groups at the 3-position in chlorophyllous pigments were reduced more rapidly than those at the 8-position. From the reports that reactions of 3-CHO with amines were preferable to those of 7-CHO, the CO functional groups on the pyrrole A-ring of chlorophylls are more reactive than those on the B-ring.     

Effect of type of peroxide on cross-linking of poly(l-lactide)

Poly(l-lactide) (PLLA) was cross-linked with various types of peroxides under constant mole ratios of peroxide-derived radicals to PLLA during reactive extrusion. Peroxides were classified into three groups according to their decomposition rates (Group I: fast, Group II: moderate and Group III: slow) and comparisons were performed within each group. Cross-linking behavior was readily understood in terms of free radical efficiency and hydrogen abstraction ability of radicals. In the case of Groups II and III, the weight-average molecular weight (M_w) of cross-linked PLLA increased with overall hydrogen abstraction ability, because slow decomposition caused uniform cross-linking in molten PLLA. In Group I, M_w and gel fraction were higher than other groups despite Group I's lower hydrogen abstraction ability, leading to the conclusion that peroxide decomposition localized in solid PLLA caused partial cross-linking because of rapid decomposition. Furthermore, the efficiency of peroxide-induced cross-linking was investigated using the Charlesby-Pinner equation.     

Generation of nitrene by the photolysis of N-substituted iminodibenzothiophene

To evaluate the ability of dibenzothiophene N-substituted sulfilimines as photochemical nitrene sources, their photolyses in the presence of several trapping reagents, such as sulfides, olefins, and phosphorus compounds, were performed. In the reactions, the corresponding imino-transfer compounds, namely sulfilimines, aziridines, and iminophosphoranes, were formed in good yields, indicating dibenzothiophene N-tosyl and N-acylsulfilimines have a potent nature as nitrogen sources.