Abstract: Reported here are the DNMR spectra of intramolecular processes of some diamagnetic complexes which were synthesized by the reactions of Zn(Ⅱ), Cd(Ⅱ) and Hg(Ⅱ) with 1,3PDTA (1,3-propanediaminetetraacetic acid), respectively. The rate constants and other thermodynamic parameters were obtained by the complete line shape anaylsis. The intramolecular exchange processes are discussed in this paper. It was found that the activation energies of these metal complexes are related to the electrostatic potential of the metal ions.

Key words: Zn, Cd and Hg-1,3 PDTA complexes, Intramolecular exchange, DNMR