Silver Ion Selective Extraction with Dithiaza-, Tetrathiaza-, and Tetrathiadiazacrown Ether Derivatives.

Dithiazacrown, tetrathiazacrown, and two tetrathiadiazacrown ether derivatives, bearing a phenyl group on each nitrogen atom at the periphery, were synthesized, and the solvent extractions of some transition metal ions with these compounds were carried out using an H2O–1,2-dichloroethane system. All of the thiazacrown compounds employed exhibited Ag+ selectivity, and formed 1 : 1 : 1 complexes of Ag+ : ligand : laurate ion as a counter anion to be extracted into a 1,2-dichloroethane solution. The extractabilities (extraction constants, Kex) for Ag+ decreased in the order: 7,16-diphenyltetrathia-7,16-diaza-18-crown-6 (3) (log Kex = 1.18 ± 0.13) > 13-phenyltetrathia-13-aza-15-crown-5 (2) (0.75 ± 0.09) > 7-phenyldithia-7-aza-9-crown-3 (1) (−0.47 ± 0.06) > 13,16-diphenyltetrathia-13,16-diaza-18-crown-6 (4) (−0.62 ± 0.16).