“…Intermolecular or intramolecular orbital energy gaps can effectively describe various properties of molecules, such as a molecule with a large HOMO–LUMO energy gap generally displaying good stability and high chemical hardness, while a molecule with a minor HOMO–LUMO energy gap showing good chemical reactivity, and singlet–triplet energy gap as a molecular descriptor to predict power conversion efficiency. 22,23 In this reaction system, the smaller energy gap for organocatalysts leads to better catalytic activity including higher yields, excellent selectivity, and extensive substrate compatibility, which is in agreement with experiments. Therefore, the energy gap between photocatalyst SOMO and substrate LUMO can be used as a descriptor for such reaction to predict the activity of the photocatalyst and substrate.…”