Explanation for the Emergence of a Single Chiral Solid State during Attrition-Enhanced Ostwald Ripening: Survival of the Fittest

The overabundant occurrence of single-handed chiral molecules in living systems has inspired scientists for well more than a century. A route to the evolution of a single chiral solid phase, using abrasive grinding of the crystals in contact with a saturated solution, has been demonstrated for the achiral compound NaClO3 crystallizing in a chiral space group and, recently, for an intrinsically chiral amino acid derivative. In order to obtain insight in the complex processes involved in these experiments, we developed a computer model that is based only on attrition and Ostwald ripening. We find that, besides the relative rates of attrition and Ostwald ripening, the racemization efficiency in the solution is an essential parameter in the deracemization process. For high efficiency the evolution to single chirality is stochastic, whereas for lower values the process becomes increasingly deterministic and the handedness of the single chiral solid end state is readily controllable. The results show excellent agreement with experimental data and allow a further optimization of this promising deracemization technique.