The canonical double helical π-stacked array of base pairs within DNA interior has inspired the interest in supramolecular double helical architectures with advanced electronic, magnetic and optical functions. Here, we report a selective-recognized and chirality-matched co-assembly strategy for the fabrication of fluorescent π-amino acids into double helical π-aggregates, which show exceptional strong circularly polarized luminescence (CPL). The single crystal structure of the optimal combination of co-assemblies shows that the double-stranded helical organization of these π-amino acids is cooperatively assisted by both CH-π and hydrogen-bond arrays with chirality match. The well-defined spatial arrangement of the π-chromophores could effectively suppress the non-radiative decay pathways and facilitate chiral exciton couplings, leading to superior CPL with a strong figure of merit (glum = 0.14 and QY = 0.76). Our findings might open a new door for developing DNA-inspired chiroptical materials with prominent properties by enantioselective co-assembly initiated double helical π-aggregation.
Here, we designed symmetric and dissymmetric chiral V‐shaped pyrenes by linking achiral pyrenes to trans‐1,2‐cyclohexane diamine scaffolds with varied spacers to investigate their circular dichroism (CD) and circularly polarized excimer emission (CPEE). In molecular solution, the symmetric V‐shaped molecules (P1, P2, P3) displayed spacer‐dependent CD and CPEE originating from the intramolecular excimers while the dissymmetric V‐shaped B was silent in CD and CPEE. Upon self‐assembly, the chiral V‐shaped conformation guided a helical hexagonal packing. Notably, P1 self‐assembled into delicate superhelices with optimum chiroptical activities and the largest gCD for pyrene derivatives to date. The dissymmetric B formed two distinct hexagonal aggregates as twists and rectangular nanotubes with greatly amplified CPEE. This work demonstrates unprecedented hexagonal superhelices from chiral V‐shaped scaffolds and provides a deep insight into the relationship between molecular conformation, supramolecular architectures, and their chiroptical performance.
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