Crystal Chiral Symmetry Breaking: A Self-Seed Inducing Effect Controlled by Kinetics

Abstract

We have studied the mechanism of crystal chiral symmetry breaking through the competition between two enantiomorphs using the inducing nucleation of two seeds, one of each chirality, under an ultrasonic field. A seed, introduced into its supersaturated solution earlier only 1–2 min than another seed with opposite handedness, can dominate the chirality of final products, and when two seeds with opposite handedness were simultaneously introduced into the solution, the ee's of the final products were closely related to the proportion of the clusters of two enantiomorphs. Our result suggests that the realization of the crystal chiral symmetry breaking under an ultrasonic field is via a self-seed inducing effect controlled by kinetics, in particular, depending on the difference between the rate of secondary nucleation induced by a primary nucleus and the rate of primary nucleation, while a primary nucleus can make the solute around it pile up in one way of the same handedness as it and rapidly coalesce on the clusters of the same handedness as it, leading to a large secondary nucleation rate.