title: Acid equilibria of semi-methylthymol blue and formation constants of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with semi-methylthymol blue.
abstract: Potentiometric and spectrophotometric studies on Semi-Methylthymol Blue (SMTB or H(4)L) have been performed. The acid-base and Co(II), Ni(II), Cu(II) and Zn(II)-ligand reaction stoichiometries were determined, and the formation constants of the corresponding proton and metal complexes, and the molar absorptivities were calculated. Evidence was found for the formation of 1:1 Co(II), Ni(II) and Cu(II) complexes, and 1:1 and 1:2 Zn(II) complexes. Cu(II) formed the hydroxo-complex, Cu(OH)L(3-), but no hydroxo-complexes of the other metal ions were observed. Suggestions are made concerning the probable structure of the complexes.
authors.affiliation: Department of Chemical Technology, Faculty of Engineering, Yamaguchi University, Tokiwadai, Ube, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yoshino
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: M
authors.initials: M
authors.lastname: Kagawa