Modulating the Optoelectronic Properties of Tripodal Fluorophores Through Fluorine‐Substituted Peripheral Phenyls

Abstract

Fourteen novel tripodal fluorophores based on a central triphenylamine donor, electron-rich and polarizable divinylthiophene linker, and eight different fluorine-based substituents have been designed and prepared via a straightforward four-step sequence. Altering the peripheral F-substitution has been demonstrated to largely affect their fundamental properties such as thermal robustness (210–420 °C), the LUMO energies (ELUMO = –2.35 to –3.11 eV), the HOMO–LUMO gap (E = 2.07–2.66 eV), and the absorption/emission maxima (maxA/E = 442–478/521–678 nm). The experimental data, corroborated by DFT calculations, further revealed twofold and tunable ICT employing both central triphenylamine and auxiliary thiophene donors, and the peripheral F-substitution either boosting or switching-off two-photon absorption activity. Whereas the –SF₅ groups impart an exceptional cross-section of 1930 GM, the –COCF3 group may completely suppress the nonlinear optical response.