Solvent effects on the rate of racemization of tris(2,4-pentanedionato)cobalt(III) complexes

摘要

Tris(2,4-pentanedionato)cobalt(III) was resolved into enantiomers by column chromatography on a chiral stationary phase (CSP) consisting of (+)589-cis[Co(S-Arg)_2 (NO_2)_2] NO_3·H_2O. The elution order, determined from the ORD spectra, was found to be consistent with the one predicted from the calculated energies of the transient complexes CSP··· [M(acac)_3] based on chiral discrimination. Racemization in benzene-acetone was followed, and the rate constant and activation parameters were discussed in comparison to the literature values for chlorobenzcnc and chloroform solutions.