SILVER ION-SELECTIVE EXTRACTION WITH DITHIAZACROWN, TETRATHIAZACROWN,AND TETRATHIADIAZACROWN ETHER DERIVATIVES

Dithiazacrown, tetrathiazacrown, and two tetrathiadiazacrown ether der ivatives, bearing a phenyl group on each nitrogen atom at the peripher y, were synthesized, and the solvent extractions of some transition me tal ions with these compounds were carried out using an H2O-1,2-dichlo roethane system. All of the thiazacrown compounds employed exhibited A g+ selectivity, and formed 1:1:1 complexes of Ag+:ligand:laurate ion a s a counter anion to be extracted into a 1,2-dichloroethane solution. The extractabilities (extraction constants, K-ex) fdr Ag+ decreased in the order: 7,16-diphenyltetrathia-7,16-diaza-18-crow-6 (3) (log =1.18 +/-0.13)>13-phenyltetrathia-13-aza-15-crown-5 (2) (0.75+/-0.09)>7-phen yldithia-7-aza-9-crown-3 (1) (-0.47+/-0.06)>13, 16-diphenyltetrathia-1 3,16-diaza-18-crown-6 (4) (-0.62+/-0.16).