INTERACTION OF 2-(2'-HYDROXY)PHENYLBENZOTHIAZOLINE WITH SOME METAL IONS: DETERMINATION OF ITS DISSOCIATION CONSTANT IN AQUO-ORGANIC MEDIA

Abstract

Potentiometric titrations were carried out with 2-(2'-hydroxy)phenyl benzothiazoline (HPBT) in various 50%v/v aquo-organic media (dioxan-water, acetone-water, methanol-water, and ethanol-water) and in different percentages of dioxan. The results indicated that the ligand is a monoprotic acid with pK_a corresponding to the hydroxyl group. The pK_a value of HPBT determined in various aquo-organic media followed the regular order of the reciprocal of dielectric constant. The solid metal complexes employing HPBT were synthesized and characterized. Spectral studies of these metal complexes [M(II) = Co, Ni, Cu and Zn] complexes indicated ring cleavage and formation of bis benzylidene disulphide (BBDS) during complex formation.

KEY WORDS: 2-(2'-Hydroxy)phenylbenzothiazoline, Metal complexes, Potentiometric titrations, Dissociation constant, bis benzylidene disulphide


Bull. Chem. Soc. Ethiop. 2006, 20(1), 161-166.