In Search of the Bailar and Rây−Dutt Twist Mechanisms That Racemize Chiral Trischelates: A Computational Study of Sc^III, Ti^IV, Co^III, Zn^II, Ga^III, and Ge^IV Complexes of a Ligand Analogue of Acetylacetonate

Abstract

Two nondissociative processes, a Bailar twist that proceeds through a transition state of D3h symmetry and a Rây-Dutt twist mechanism that proceeds through a transition state of C(2v) symmetry, as well as dissociative/associative processes are potential mechanisms by which the enantiomeric forms of chiral metal trischelates can be interconverted. We have applied density functional theory to locate the stationary points for metal trischelates of a beta-diketonate ligand analogue that interconvert Delta and Lambda forms via one or both of these nondissociative pathways. Although many two-dimensional static representations of the Bailar and Rây-Dutt twist mechanisms can be found in the chemical literature (of the type shown in Figure 1), in this communication, we present our results in the form of interactive three-dimensional animations as a means of enhancing the scientific perception of these fluxional processes.