title: Acid dissociation and metal chelate formation equilibria of some halogenated diphenylthiocarbazones.
abstract: The acid dissociation constants (K(a)) of di-p-fluoro-, di-p-chloro-, di-p-bromo-, di-p-iodo-and di-m-trifluoromethylphenylthiocarbazones and the equilibrium formation constants (K(f(1))) of their 1:1 complexes with Co(II), Ni and Zn have been determined at 25 degrees in 50% v v aqueous dioxan at 0.10 M ionic strength. Each of the electron-withdrawing substituents gives a reduction in pK(a) roughly proportional to its Hammett sigma value, and log K(f(1)) increases linearly with pK(a).
authors.affiliation: Department of Chemistry University of Arizona Tucson, Arizona 85721, U.S.A.
authors.forename: A R
authors.initials: AR
authors.lastname: Al-Salihy
authors.forename: H
authors.initials: H
authors.lastname: Freise