Complexation of ethyl 2-aryl(alkyl)sulfonylamino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylates with nonferrous metal ions

Abstract

Complexation of sulfonyl derivatives of the Gewald thiophenes (SGT) with Cu(II), Co(II), Ni(II), Zn(II), and Cd(II) ions in ammonia solutions was studied. The molar ratio method, the Job’s method of continuous variation, and coductometric titration revealed ratios [M(II)]: [SGT] = 1: 2. The composition of preparatively isolated complexes was confirmed by IR spectroscopy and elemental analysis data. Solubility product constants for precipitates of the complexes and complexation equilibrium constants were calculated. Solubility product constants for M(II) complexes was shown to be dependent on the nature of sulfonyl substituent in SGT series.