Quantitative Structure–Property Relationships for Fluorescence Quantum Yield of [6]Helicene Derivatives: Kinetic, Electronic, and Vibrational Descriptors Exploration

Helicene derivatives are promising chiral emitters, but their low fluorescence quantum yield (QY) hinders the realistic applications. Quantitative structure-property relationships exploration provides a facile way for the rational design of related derivatives. Herein, we present a comprehensive theoretical study on a series of heteroatom-substituted [6]helicene to shed light on this relationship. It is found that high QY originates from a locally excited state strongly anchored in the rigid central core, which effectively suppresses nonradiative decay rates. Then, based on systematic structure-property relationships analysis, various physically meaningful descriptors, including kinetic, electronic, and vibrational parameters, are suggested. More notably, these novel descriptors, which had rarely been analyzed previously, all demonstrate high precision: the absolute correlation coefficients are generally higher than 0.80, and the strongest descriptor is up to 0.99. These findings can reveal the underlying relationship between structural effects and fluorescence properties, thus offering new strategies for designing high-brightness helicene-based emitters.