Benzo Thiacrown Compounds as Extraction-Spectrophotometric Reagents for Univalent Class b Metal Ions

Abstract

Two new thiacrown compounds in which benzoazo groups are introduced as the chromogenic group, 4’-(p-hydroxyphenylazo)benzo-1,4,8,11 -tetrathiacyclopentadec-13-ene(III) and 4’-(2-hydroxy-5-chlorophenylazo)benzo-1,4,8,1 l-tetrathiacyclopentadec-13-ene(VI), have been synthesized. Their characteristics as extracting and spectrophotometric reagents have been examined. Silver belonging to the univalent class b metals is extracted with reagent(VI) into 1,2-dichloroethane. Its absorption maximum shifts to a much longer wavelength than that of the reagent itself. Neither class a and ab metals nor bivalent class b metals such as mercury(ll) and palladium(ll) were extracted at all. Only copper(ll) of class ob metal is appreciably extracted with this reagent. It seems to proceed due to coordination to adjacent azo and phenol groups. In the presence of hydroxylamine sulfate, copper(l) is extracted into 1,2-dichloroethane-amyl alcohol (4:1).