Nano-rod structure of poly(ethylenedioxythiophene) and poly(pyrrole) as created by electrochemical polymerization using anionic porphyrin aggregates as template

It was found that a one-dimensional rodlike structure of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) in water acts as a powerful template for electrochemical polymerization of ethylenedioxathiophene (EDOT) and pyrrole on an ITO electrode. Examination using CV and UV-vis spectroscopic examinations established that J-aggregated TPPS molecules are entrapped in the resultant poly(EDOT) and poly(pyrrole) films. SEM observation established that these monomers are electrochemically oxidized to grow up to a nanosized rodlike structure, reflecting the aggregation structure of TPPS. [structure: see text]     

Absolute configuration of aflastatin A, a specific inhibitor of aflatoxin production by Aspergillus parasiticus

Aflastatin A (1) is a specific inhibitor of aflatoxin production by Aspergillus parasiticus. It has the novel structure of a tetramic acid derivative with a long alkyl side chain. The absolute configurations of 29 chiral centers contained in 1 were chemically elucidated in this study. First, four small fragment molecules were prepared from 1 or its methyl ether (2), and their absolute structures were assigned as N-methyl-D-alanine, (2S,4R)-2, 4-dimethyl-1,6-hexanediol dibenzoate, (R)-3-hydroxydodecanoic acid, and (R)-1,2,4-butanetriol tribenzoate. Next, an acyclic fragment molecule 3 with 13 chiral centers was obtained from 1 by NaIO(4) oxidation, and its relative stereochemistry was elucidated by J-based configuration analysis. By analyzing coupling constants of (3)J(H,H) and (2,3)J(C,H) and ROE data, the relative configuration of 3 was verified. Finally, by further J-based configuration analysis using a fragment molecule 7 prepared from 2 with 28 chiral carbons, all relative configurations in the alkyl side chain of 1 were clarified. By connecting these relative configurations with the absolute configurations of first four fragment molecules, the absolute stereochemistry of 1 was fully determined.     

Spatially,temporally, and spectrally resolved measurement of laser-induced plasma in air

Images and emission spectra of sparks produced by laser-induced breakdown in air were investigated with a high degree of spatial and temporal resolution. The laser-induced breakdown was generated by focusing a 532-nm nanosecond pulse from a Q-switched Nd:YAG laser. The data were collected using a framing intensified charged coupled device (CCD) camera and a multi-fiber Cassegrain optics system coupled to an intensified CCD spectrometer. The results provided information about the different stages of laser-induced breakdown. The plasma shape and emission spectrum were very reproducible. Different ionization levels in the plasma kernels, which were observed using the high spatial resolution of the multi-fiber Cassegrain optics system, occurred during the plasma formation and cooling and at different locations within the plasma. This was due mainly to the thickness of the plasma relative to the laser wavelength, which created different ionization levels and energy absorption rates throughout. These observations were correlated with the plasma visualizations obtained with the framing ICCD camera. The plasma emission analysis permitted us to study the temperature evolution along the plasma during the laser-induced breakdown process. The analysis demonstrated the validity of a laser-supported wave model during the first stages of laser-induced breakdown and illustrated the weak dependence of the plasma temperature on the input energy. PACS 52.50.Jm; 52.70.-m; 51.50.+v     

Failure of color constancy for high luminance of a test patch that appears unnatural as an object in a space

The theory of the recognized visual space of illumination (RVSI) is that the color appearance of objects in a space is determined in relation to its recognition axis RX whose direction is determined by the brain action to adapt to the illumination in the space. Thus the color constancy holds. RX is applicable to objects in the space but not to an object or a portion that does not belong in the space in terms of illumination, that is to say, the luminance of which is too high based on the illumination for that space. In that case the color appearance would be determined in relation to the fundamental axis FX and the color constancy would not hold. In the present paper the chromaticity points were measured for a test patch that appeared achromatic for various luminance of the patch. The points were close to the color of illumination to indicate the color constancy when the luminance was low enough to assure its appearance as the object color, but they departed from the color of illumination and approached the colorimetrically achromatic color. The color constancy gradually failed for the test patch with the high luminance when the color mode became an unnatural object color and then a light color.     

Effect of supports on the acitivity of Mo and Fe catalysts for the reduction of NO with H2

In the reduction of NO with H₂, MoO₃–ZrO₂ and Fe₂O₃–SiO₂ were found to be the most active among each ten kinds of a series of Mo and Fe catalysts. On the basis of an IR study, the high catalytic activities were conclued, to be caused by the ability of the catalysts to the formation of adsorbed NO^– species.

---

, NO H₂, MoO₃–ZrO₂ Fe₂O₃–SiO₂ Mo Fe. - , NO^–.

     

Chemisorption bonds on nickel and palladium surfaces studied by substitution reactions of various organic molecules

The substitutional chemisorption of benzene, pyridine, aniline, toluene, nitrobenzene and ethylenediamine on nickel and palladium has been studied at 295 K by X-ray photoelectron spectroscopy. Pyridine is more strongly bonded to nickel than benzene and is not substituted by benzene, while benzene is more strongly adsorbed on palladium than pyridine. Ethylenediamine and aniline chemisorb molecularly on palladium in contrast to the easy dissociation on nickel giving the species containing a NH^? group. The different bonding nature of nickel and palladium surfaces is discussed by considering the electron donating or withdrawing tendency of the adsorbates and the other substitution data: (a) nitrobenzene displaces completely the adsorbed benzene on nickel and slightly the pyridine; (b) the strengths of the chemisorption bonds on palladium decrease in the order, ethylenediamine > aniline ? toluene > benzene > pyridine.