Symmetry Breaking: Orchestrating Dynamics in Molecular Crystals

Symmetry breaking serves as a highly efficient construction strategy for organic molecular crystals. This approach enables multilevel control, allowing for modifications at the molecular level and adjustments at the supramolecular level by tuning the molecular packing modes in the crystal lattice. Ultimately, this grants the molecular crystals dynamic adaptive capabilities at the macroscopic scale. Recently, the regulation of crystal topological structures and the construction of multifunctional crystalline materials have garnered significant research interest. Specific areas of focus include modulating helical packing, exploring photoresponsive behavior, developing flexible crystals, and investigating single-crystal-to-single-crystal transformations. However, effectively integrating and utilizing symmetry-breaking effects in crystalline systems to achieve novel functionalities remains a pressing challenge. Addressing this challenge may require the combination of precise crystal engineering strategies and sophisticated molecular design, particularly for chiral molecules. This perspective, therefore, highlights recent advances in dynamic molecular crystals achieved through molecular and packing asymmetry. It aims to offer guidance and new insights for rational designing and understanding future molecular crystals with improved dynamic properties and functionalities.