Controlling Asymmetry Amplification Through Supramolecular Polymorphism

Supramolecular polymorphism has recently emerged as a powerful concept, enabling a single chemical entity to form distinct, stable assemblies in solution with diverse morphological, photophysical, and electronic properties. Despite this progress, the interplay between supramolecular polymorphism and chirality remains unexplored. Herein, we harness supramolecular polymorphism to control the amplification of asymmetry in supramolecular polymerization (SP). For this purpose, we designed two Pt(II) complexes bearing π-extended ligands and S- or R-chiral side chains (compounds (S)-1 and (R)-1) that self-assemble into two distinct supramolecular polymorphs in methylcyclohexane: nonemissive short fibers with parallel molecular packing (AggI) and thermodynamically more stable helical fibers with a rotationally offset stacking, closer Pt⋯Pt contacts, and weak ³MMLCT luminescence (AggII). These polymorphs exhibit markedly different amplification of asymmetry in majority rules (MR) and sergeants-and-soldiers (SaS) studies, with the thermodynamic polymorph displaying superior performance. Ultimately, coassembly studies between the achiral model compound 2-which exhibits strong ³MMLCT emission in the assembled state-and the chiral but weakly emissive AggII reveal a synergistic communication between chirality and luminescence, culminating in the emergence of circularly polarized luminescence (CPL). This study broadens the scope of supramolecular polymorphism and expands the design toolbox for adaptive supramolecular materials with emergent and synergistic functionalities.