Tetsutaro Yoshinaga

Photophysical and photochemical processes of 9,10-dihydro-9-silaanthracenes: photochemical generation and electronic structure of 9-phenyl-9-silaanthracene

Abstract Photophysical processes of 9,10-dihydro-9-silaanthracene ( 1 ) and its 9-phenyl derivative ( 2 ) have been studied in 3-methylpentane at 77 K. Photolyses of these compounds have been carried out at 77 K and reaction intermediates have been studied. Carbon-centered radicals and silylenes have been observed for 1 , while for 2 , formation of carbon-centered radicals and 9-phenyl-9-silaanthracene has been confirmed by use of UV–vis absorption spectrum, fluorescence spectrum, fluorescence polarization and results of semi-empirical MO calculations. The electronic structure of 9-silaanthracene has been discussed in comparison with that of anthracene.

Solid surface enhancement effects on chemiluminescence. II. Diaryloxalate and polymers as media solids

Abstract Solid surface enhancement effects on chemiluminescence were studied using several natural and synthetic polymers. The influence of surface conditions of cellulose on the chemiluminescence of powder and filter paper was also examined. Intensities for powder were relatively low compared to paper. The influence of packed powder and transparent film with the same particle size was examined for PVA, PVC and acetylcellulose. Each polymer showed similar chemiluminescent properties for film state, irrespective of their different chemical structures. Also studied were the effects of functional groups on the chemiluminescence intensity and lifetime of cellulose derivatives (cellulose, acetylcellulose, chitin and chitosan) in powder states. Finally, this paper discusses the relationship among intensities, lifetime and chemiluminescence energies for the respective samples.

Photochemical reaction intermediates of benzyl chloride in condensed phase

Reaction intermediates produced upon the photolysis of benzyl chloride have been studied in glassy matrix and in solution. In the steady-state photolysis both benzyl radicals and structural isomers of benzyl chloride were formed in ethanol, while in 3-methylpentane the structural isomers were predominantly formed. The nanosecond laser photolyses of benzyl chloride in ethanol and in cyclohexane also generated benzyl radicals and structural isomers at room temperature. In acetonitrile, in addition to these species, benzyl cations were observed in the early stage after the photolysis.

Preparation and Optical Resolution of a New Helical Lactone Carrying the 2,8-Dioxabicyclo[3.3.0]octane Ring System

A new overcrowded lactone (3) carrying the 2,8-dioxabicyclo[3.3.0]octane ring system was prepared by a simple treatment of tetraol (1) (prepared from 2,7-dihydroxynaphthalene and glyoxal) with 3,5-xylenol, and readily resolved into its enantiomers having a specific rotation of >800° (absolute value). A preliminary experiment demonstrated that 3 would be a promising resolving agent.

Preparation and Stereochemistry of the Isopropylidene Derivatives of 1,2‐Dihydronaphtho[2,1‐b]Furan‐1,2‐Diol and 1,2,9,10‐Tetrahydronaphtho[2,1‐b:7,8‐b′] Difuran‐1,2,9,10‐Tetraol in Comparison with the Corresponding Acetyl Derivatives

Abstract 1,2‐Dihydronaphtho[2,1‐b]furan‐1,2‐diol and 1,2,9,10‐tetrahydronaphtho[2,1‐b:7,8‐b′]difuran‐1,2,9,10‐tetraol were transformed into the corresponding isopropylidene derivatives, which were studied mainly by 1H NMR and chiral HPLC analyses in terms of a possible transformation mechanism and stereochemistry in comparison with their corresponding acetyl derivatives.

Determination of chloride ion in ultra-fine particles of silver, copper and copper(I and II) oxides.

銀超微粒子,銅,及び酸化銅超微粒子中の塩化物イオンを還流抽出法により純水中に抽出し,チオシアン酸水銀を用いる吸光光度法により測定した.抽出曲線(塩化物イオンの抽出量-還流時間曲線)は極大値をもつ特異な形のものが得られた.その極大値と試料採取量のプロットから得られる原点を通る直線の傾きから塩化イオンを定量した.