Interaction of nickel-, cobalt-, zinc- and lead(II) with benzothiazole-2-carboxyhydrazides in solution: Synthesis of their copper(II) complexes

The Cu-II completes of benzothiazole-2-carboxyhydrazide (BTCH), benzthiazole-2-(1-N-methyl)carboxyhydrazide (BTCMH) and benzothiazol-2(1-N-phenyl)carboxyhydrazide (BTCPH) have been synthesized. Proton-ligand constants of ETCH, BTCPH and BTCMH and metal-ligand formation constants of their binary complexes with Ni-II, Co-II, Zn-II and Pb-II have been determined in 70% (v/v) DMF-water medium at 303 K and 0.1 M (KNO3) ionic strength. The formation constants follow the order : log K-1 > log K-2 for all the complexes. The stability order with respect to ligands follows the sequence : M(II)-BTCMH > M(II)-BTCH > M(II)-BTCPH.