Dynamic nuclear magnetic resonance of zinc and cadmium complexes of 1,2-propanediaminetetraacetic acid

✍ Scribed by Fei Li; Ruifang Song

• Book ID: 102529547
• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 431 KB
• Volume: 29
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260290718

✦ Synopsis

Abstract

The ^1^H NMR temperature dependence of the zinc(II) and cadmium(II) complexes of 1,2‐propanediaminetetraacetic acid (1,2‐PDTA) was investigated. The four AB patterns in the ^1^H NMR spectra of the acetates of the complexes were assigned with the aid of computer‐simulated spectra at various temperatures. The AB interchange phenomena due to nitrogen inversion were observed in the temperature range 90–148°C. The rate constants and the activation parameters were calculated. It is shown that the nitrogen‐inversion rates of the two asymmetric nitrogen atoms are different, both for Zn(1,2‐PDTA)^2−^ and for Cd(1,2‐PDTA)^2−^, and that those of the nitrogen atom on the same side as the methyl group are slower. A water displacement mechanism in the process of nitrogen inversion is proposed on the basis of the kinetic data.