Stereochemical studies of coordination complexes. : I. Spectropolarimetric titrations of metal ions using D-(-)-Trans-1,2-cyclohexanediaminetetraacetic acid. II. Optical rotatory dispersion and circular dichroism studies of transition metal complexes of stereospecific ligands

Abstract

A method is described for the spectropolarimetric titrations of the group IIA and lanthanide (III) metal ions using D-(-)-trans-1,2-cyclohexanediaminetetraacetic acid (D(-)CDTA) as the titrant. A photoelectric polarimeter was used to monitor continuously the optical rotation of the solution during the course of the titration; the titrant and metal complexes formed are optically active and serve as self-indicators. Experimental conditions necessary for the successful application of spectropolarimetric titrimetry are discussed. The range of average deviations from visual chelometry for the Group IIA metal ions titrated spectropolarimetrically was 0.00-0.17%; for the twelve lanthanide (III) metal ions the average deviations ranged from 0.00-0.39%. The spectropolarimetric titrations of the Group IIA and lanthanide (III) metal ions with D(-)CDTA had precisions equal to or greater than visual chelometric titrations. ...