Kanji Kubo

PET fluoroionophores for Zn2+ and Cu2+: complexation and fluorescence behavior of anthracene derivatives having diethylamine, N-methylpiperazine and N,N-bis(2-picolyl)amine units

Anthracene derivatives (1, 2) having one or two diethylamine (a), N-methyl-piperazine (b) and N,N-bis(2-dipicolyl)amine units (c) showed weak emission, suggesting that photoinduced electron transfer (PET) from the amine group to the excited anthracene occurs. The PET fluoroionophores (1, 2) were found to display unique photophysical properties in the presence of the guest metal salts. Complexation of diethylamine (1a, 2a) and N-methyl-piperazine derivatives (1b, 2b) with Ni2+, Cu2+ and Zn2+ enhanced the emission, while the emission intensities of N,N-bis(2-picolyl)amine derivatives (1c, 2c) are increased in the presence of Zn2+ and decreased in the presence of Ni2+ and Cu2+. The crystal structures of 2c and its zinc chloride complex showed that the binding of Zn2+ to the N,N-bis(2-picolyl)aminomethyl unit inhibits the photoinduced electron transfer process. Intramolecular π–π interactions between anthracene and the ZnCl2-complexed pyridine were observed.

Crystal structures of coumarin-3-carbamate derivatives with herbicidal activities

Coumarin-3-carbamate derivatives were prepared by the reaction of alcohols with coumarin-3-carbonyl azide. The testosterone derivative has herbicidal activities, but the benzene derivative does not have the activities. The crystal structures of two coumarin-3-carbamate derivatives were analyzed by X-ray crystallography. The crystals of the testosterone derivative had intermolecular N-H···O, C-H···O, and C-H···π interactions.

5-Benzyl-1,3,5-trimethylpyrimidine-2,4,6(1H,3H,5H)-trithione

Barbiturates act as central nervous system depressants and produce a wide spectrum of effects, from mild sedation to anesthesia (Bideau et al., 1976; Gotthardt et al., 1980). Some are also used as anticonvulsants. Although a number of barbiturates have been studied, there have been only a few studies of their sulfur analogs (trithiobarbiturate) (Greenberg et al., 2000) and while most crystals of barbiturates are colorless those of thiobarbiturates, such as (I), are usually colored.