Abstract
A bisthiacrown compound bearing two chromogenic groups, which can function as a counter anion, was synthesized. Its characteristics as an extractive-spectrophotometric reagent for the soft bivalent metal ions were examined and compared with those of a mono-type thiacrown compound. The soft univalent metal ions such as silver(I) and copper(I) were well extracted. The soft bivalent metal ions, cadmium(II) and mercury(II), were also well extracted with this bis-type reagent. Accordingly, the extraction behavior was different from that of the mono-type thiacrown compound. Cobalt(II), nickel(II) and zinc(II) were not significantly extracted, but copper(II) was appreciably extracted with this reagent. Of the five metal ions extracted with this bis-type reagent, cadmium(II) and copper(II) complexes in organic solvents exhibit an absorption maximum at similar wavelengths, but at considerably shorter wavelengths than copper(I), silver(I) or mercury(II).
