Dynamic Features of the Ethylenediaminetetraacetate Complexes of Ca, Sr, Ba, and Co(II) in Aqueous Solutions Studied by the Ultrasonic Absorption Method

Article abstract of DOI:10.1021/ja00521a024

Ultrasonic absorption was measured in aqueous solutions of ethylenediaminetetraacetate(EDTA) complexes of Ca, Sr, Ba, and Co(II) (1:1 complex).The absorption was ascribed to the configuration change reaction of the complex, i.e., pentacoordinated structure <*> hexacoordinated structure (k_f, k_b).Rate constants k_f,k_b and the volume change of the reaction ΔV were obtained.The rate constant was discussed in relation to the coordinated water substitution rate constants of the metal ions with use of a step-by-step mechanism.Supplementary work is reported for the Co(II) complex solutions of EDTA-related ligands.