CARBON-13 NMR: A TOOL FOR STUDYING DEUTERIUM EXCHANGE KINETICS IN COBALT(III) AMINOCARBOXYLATES

Abstract

Abstract Carbon-13 nmr spectral assignments of some Cobalt(III) Aminocarboxylates are presented. Natural abundance 13C spectra were obtained with a Varian Associates XL-100/15 FT nmr spectrometer equipped with an integration subroutine and a broad band proton decoupler. The kinetics of deuterium substitution on glycinate rings of Co(III)EDTA, Co(III)CyDTA, and Co(III)PDTA were studied. Rate constants obtained here are in good agreement with those obtained in previous pmr studies. Rate constants for some glycinate proton exchanges that were previously unattainable by pmr are also presented. The advantages of using 13C nmr over pmr in these studies are discussed. This study was done at 95°C and pD = 1.5. The rate of isotopic exchange was monitored by the decrease in the proton decoupled integral of the 13C resonances.