Synthesen von α,β-ungesättigten 2-(2-Oxo-benzazolin-3-yl)-3-hydroxy-dithio-carbonsäure-alkylestern und entsprechend substituierten Keten-S,S-acetalen sowie deren Kristall- und Molekülstruktur

Summary The new alkyl 2-(2-oxo-benzazoline-3-yl)-3-hydroxy dithiocrotonates and dithiocinnamates4 and the corresponding ketene dithioacetals2 and5 are obtained by dithiocarboxylation of the 3-acceptormethyl substituted benzazoline-2-ones1 or3. Alkylation at room temperature gives compounds4 whereas at higher alkylation temperature2 or5 are formed. The results of X-ray analyses performed for methyl 3-hydroxy-p-chloro-dithiocinnamate4d and of N-[1-(4-chloro-benzoyl)-2,2-bis(methylthio)-vinyl]-benzothiazoline-2-one5e are discussed.

     

Halide interferences in an electrothermal graphite furnace atomic absorption spectrometry with group IIIB elements as studied by atomic and molecular absorption signal profiles

Molecular absorptions of monohalides (MX; X = F, Cl and Br) of alkali metals, alkaline-earth metals and Group IIIB elements produced in a conventional electrothermal graphite furnace atomizer have been observed by a rapid measurement system. Their characteristic data are summarized as appearance and peak temperatures and the analytical sensitivities. Furthermore, molecular absorptions ofAlF and InF are utilized to study the interference of fluoride with aluminum and indium atomic absorptions. Although the formations of AlF and InF suppress the atomic absorptions ofAl and In, respectively, the time-overlap in signal appearance of atomic absorptions of these two elements and molecular absorptions of their monofluorides is not observed. This is contradictory to pure “vapor phase mechanism”, and indicates that processes occurring on the graphite surface are also important. Usefulness of strontium nitrate as a matrix modifier for the determination of indium was also demonstrated.