Enantiodiscrimination through Oriented Attachment: Formation of Homochiral Crystal Aggregates from a Racemic System

TL;DR

This study demonstrates that racemic NaBrO3 crystals can self-assemble into large homochiral aggregates through enantioselective oriented attachment, revealing a new mechanism of chiral recognition and aggregation.

Contribution

It introduces a novel enantiodiscrimination mechanism via oriented attachment, leading to homochiral crystal aggregates from racemic systems.

Findings

Crystals self-aggregate with enantioselectivity

Aggregation exhibits crystallographic directionality

Process extends to other chiral molecules

Abstract

We show that D- and L-enantiomorphous crystals of NaBrO3 in equilibrium with the corresponding solution, self-aggregate leading to large crystal assemblies. Surprisingly, crystal-to-crystal interaction is not a random process and takes place with nearly complete enantioselection (chiral recognition) thereby providing homochiral aggregates. There is in addition a crystallographic directionality and many aggregates grow as a whole. The process can be extended to enantiomorphous NaClO3 crystals under milder conditions as well as crystals of inherently chiral molecules such as a proteinogenic amino acid.