Abstract: The DNMR Spectra of the intramolecular processes occurring in Mg-, Ca-, Sr-and Ba-1,2-propylenediamine-tetraacetic acids(1,2-PDTA) are reported in this paper. The relative activation parameters have been obtained by performing computer line shape analysis. The experimental results show that the rates of the lone pair inversion of the two nitrogen atoms in these complexes are different, but their activation energies are similar. The nitrogen inversion process of these complexes belongs to twist mechanism through a trigonal prismatic intermediate.

Key words: Mg,Ca,Sr,Ba-1,2 PDTA, Intramolecular processes, DNMR