Synthesis of chloroboron(III) 3,4,12,13,21,22- hexabromosubnaphthalocyanine under high dilution conditions and comparative studies of effects of halogenation on physicochemical properties of subnaphthalocyanines

Chloroboron(III) hexabromosubnaphthalocyanine was prepared by cyclotrimerization of 6,7-dibromo-2,3-naphthalenedicarbonitrile in the presence of BCl₃ under high dilution conditions, that is 7.4?mM of dicarbonitrile in o-dichlorobenzene-xylene (1:1). It was converted to fluoroboron(III) hexabromosubnaphthalocyanine by the reaction with AgBF₄. Fluorescence quantum yields of chloroboron(III) hexafluoro-, hexachloro-, hexabromo-, and hexaiodosubnaphthalocyanine were 0.22, 0.20, 0.11, 0.05, respectively, indicating that heavy atom effects of Br and I effectively deactivated the singlet excited states. Thermal decomposition temperature (5% weight loss in the TG curve) of fluoroboron(III) hexabromosubnaphthalocyanine was the highest (359?°C) and that of chloroboron(III) hexafluorosubnaphthalocyanine was the lowest (221?°C) among hexahalosubnaphthalocyanines. The hexabromosubnaphthalocyanine served as a substrate of Sonogashira coupling, and proved to be a useful intermediate for further functionalization of subnaphthalocyanines.     

Isolation of a Nitromethane Anion in the Calix-Shaped Inorganic Cage

A calix-shaped polyoxometalate, [V₁₂O₃₂]⁴⁻ (V12), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of an anion. The highly-reactive cyanate is smoothly trapped by V12 to form [V₁₂O₃₂(CN)]⁵⁻. In the CH₃NO₂ solution, cyanate abstracts protons from CH₃NO₂, and the resultant CH₂NO₂⁻ is stabilized in V12 to form [V₁₂O₃₂(CH₂NO₂)]⁵⁻ (V12(CH₂NO₂)). A crystallographic analysis revealed the double-bond characteristic short bond distance of 1.248 Å between the carbon and nitrogen atoms in the nitromethane anion in V12. ¹H and ¹³C NMR studies showed that the nitromethane anion in V12 must not be exchanged with the nitromethane solvent. Thus, the V12 container restrains the reactivity of anionic species.     

Antioxidant ortho-benzoyloxyphenyl acetic acid ester,vaccihein A,from the fruit of rabbiteye blueberry (Vaccinium ashei)

A new ortho-benzoyloxyphenyl acetic acid ester, called vaccihein A (1), was isolated from the fruit of rabbiteye blueberry (Vaccinium ashei). The chemical structure was determined on the basis of spectroscopic data. Compound 1 had antioxidative activity using the ferric thiocyanate method. In addition, 1 showed a scavenging effect on the stable free radical 1,1-diphenyl-2-picrylhydrazyl.     

Achromatically injection-seeded terahertz-wave parametric generator

An achromatically injection-seeded terahertz-wave parametric generator was constructed with MgO:LiNbO (3) crystals and a tunable seeder in a stationary dispersion-compensated optical arrangement. Without readjusting the mirrors, we obtained smooth tuning of the terahertz wave over the 0.6-2.6 THz range by adjusting the seeder wavelength alone. We have successfully demonstrated the feasibility of this system for terahertz-wave absorption measurements over a wide frequency range by using low-pressure water vapor.     

Titanate nanotube thin films via alternate layer deposition

Layer-by-layer growth of titanate nanotubes on glass substrates was achieved by alternate layer deposition using an aqueous solution of colloidal titanate nanotubes and that of a polycation. Even a single layer thin film of titanate nanotube shows high photoinduced hydrophilicity.     

New gemini organogelators linked by oxalyl amide: organogel formation and their thermal stabilities

New gemini organogelators linked by an oxalyl amide that can be easily, effectively, and cheaply synthesized have good organogelation abilities and their cyclohexane gels have superior thermal stabilities; especially 7 possessing the branched alkyl ester can gel at 0.7 wt% cyclohexane even at 70°C.     

A new triterpene glucosyl ester from the fruit of the blackberry (Rubus allegheniensis)

A new triterpene glucosyl ester, rubusside A, has been isolated from the fruit of the blackberry (Rubus allegheniensis PORT.) along with a known triterpene glucosyl ester, niga-ichigoside F1. The chemical structure of rubusside A was determined on the basis of spectroscopic data as well as chemical evidence.     

Catalytic ring hydrogenation of phenol under supercritical carbon dioxide

A charcoal-supported rhodium catalyst was highly active for the ring hydrogenation of phenol and cresols under supercritical carbon dioxide.     

Comparison of characteristic temperatures determined by Mössbauer spectroscopy and X-ray diffraction

Characteristic temperatures have been determined by both Mössbauer spectroscopy and X-ray diffraction for Prussian blue analogs of the type Fe[M(CN)₆] (M=Co, Rh and Ir). For each Fe³⁺ in these compounds, the characteristic temperatures obtained from the Mössbauer parameters agree in tendency with those from the X-ray powder diffraction data. The values of the former are lower than those of the latter. This difference is thought to be caused by the different nature of the observed objects interacting with the electromagnetic waves, i.e. γ-ray and X-ray.