Competition between Bailar and Ray-Dutt paths in conformational interconversion of tris-chelated complexes: a DFT study

摘要

Tris-chelated complexes of aluminum with α-isopropenyltropolonate and α-isopropyltropolonate ligands can be considered prototypical complexes for the study of internal rearrangements through prismatic transient structures. Such isomerization paths, known as Bailar and Ray-Dutt twists, have been suggested for these compounds on the basis of dynamic NMR study, but modern computational methodologies have never been applied to corroborate this finding. In this paper, we report a computational investigation about the internal isomerization processes of the mentioned complexes. Both the Bailar and Ray-Dutt twists have been found as possible reaction paths. The prismatic structures along each reaction path have been described as transition structures rather than intermediate and have been computationally characterized. A comparison between experimental and computational kinetic data has been performed.