Pnictogen Bond-Mediated Coassemblies for Noncovalent Molecular Glass

Pnictogen bond (PnB) occurring on the group-15 elements is recognized as σ- or π-hole-based interaction that has garnered attention in the fields of anion recognition and organocatalysis. Due to the polyvalent feature of pnictogens and high directionality, PnB possesses potential in the design of convergent coassembled materials with acceptors containing lone pair electrons or anions, which however is rarely explored so far. Herein, we unveil the role of antimony (Sb)-based PnB donors in producing self-assembled chiroptical materials with lone pair electron containing acceptors. Steric effect and electronic properties determined the exposure and strength of σ-holes that direct the complexation between components. PnB complexation leads to profound property and self-assembly behavior evolutions compared to the pristine assembly, including crystallinity, photophysical, morphological, and chiroptical properties. The PnB complexes exhibited an accelerated photoisomerization. Ascribed to the multiple σ-holes in Sb donors, amorphous structures were generated, enabling the formation of glassy materials.