A 59-Cobalt NMR Investigation of the Hydrogen/Deuterium Exchange Kinetics in Cobalt(III) Complexes

Currently, the hydrogen/deuterium exchange kinetics in cobalt(III) complexes are being investigated. In the presence of deuterated solvents, (e.g. D2 0 and CH3CH20D) the amine hydrogens in the complexes are exchanged for deuteriums. For the hexaamminecobalt(III) ion, 19 isotopmers (H18D0 to HOD 18) are possible. For the tris(ethylenediammine)cobalt(III) ion, 13 isotopmers (HI 2D0 to HOD 12) are possible. Each hydrogen/deuteruim exchange causes a shift in the observed 59Co resonance of approximately 6 ppm. The rate constant of the hydrogen-deuterium exchange for the first H-D exchange has been determined as a function of solvent. When the chosen solvent is D20, the rate constant is 1.09 x 10° sec"1 for the hexaamminecobalt(III) ion. In methanol-d, the rate constant is 1.82 x 10"4 sec"'. Electronic effects of ligands have also been investigated. Experimental conditions (e.g., observation frequencies and solution parameters) and the representative NMR spectra are presented.

Name thesis:degree_name

Master of Science

Year

2003

Author dc:creator

• McCombs, Michelle

• Chemistry

Repository record dc:identifier

https://digitalcommons.wku.edu/theses/554

OAI identifier oai:identifier

oai:digitalcommons.wku.edu:theses-1557