title: Study on Semi-Glycinecresol Red complexes with bivalent metal ions.
abstract: Semi-Glycinecresol Red (SGCR or H(3)SGCR) was purified by means of chromatography on cellulose and by cation-exchange. A potentiometric, spectrophotometric and ESR study on the complex formation equilibria of several bivalent metal ions with SGCR was performed. The acid-base and metal-ligand stoichiometries were determined, and the formation constants, lambda(max) and absorptivities of the visible-region absorption spectra of the corresponding proton and metal complexes were determined. The copper complexes were examined by ESR spectroscopy. Each metal ion was found to form the 1:1 and 1:2 (metal:ligand) complex species, MSGCR(-) and M(SGCR)(4-)(2), in alkaline solution. However, only Cu(II) was found to form the protonated complexes, CuHSGCR and Cu(HSGCR)(2-)(2), in weakly acidic media. SGCR is suitable as an indicator for Cu(II) in a weakly acidic solution and for Cu(II), Zn(II) and Pb(II) in alkaline solution.
authors.affiliation: Department of Chemical Technology, Faculty of Engineering, Yamaguchi University, Tokiwadai, Ube 755, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yoshino
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: K
authors.initials: K
authors.lastname: Arita
authors.forename: K
authors.initials: K
authors.lastname: Ishizu