Achieving Chiral Crystallization through Tailored Silyl-Substituted Dipolar Molecular Designs

Herein, we present a molecular design based on trimethylsilyl (TMS)- and triisopropylsilyl (TIPS)-substituted dipolar units, which enable the formation of chiral crystals (P212121 space group) from achiral molecules. Single-crystal X-ray diffraction analysis revealed that the smaller steric effects introduced by the TMS led to the formation of crossed chiral dimers, while the bulky TIPS groups acted as shielding sites, allowing the chiral dimers to stack one-dimensionally into polar chains via dipole–dipole interactions of 2,3-difluorobenzene units with 21 helical symmetries. Comparative analyses of related derivatives indicated that a delicate balance is required in the molecular design to achieve such chiral assemblies. This study highlights the importance of introducing appropriate bulky shielding sites and interactive sites to achieve chiral crystallization and provides valuable guidance for designing chiral assemblies from achiral dipolar molecules.