Two-photon absorption and fluorescence fluoride-sensing properties of N-octyl-3,6-bis[4-(4-(diphenylamino)phenyl)phenyl]-1,4-diketo-pyrrolo[3,4-c]pyrrole

Abstract

A fully aromatic D–π–A–π–D-type molecule 3,6-bis[4-(4-(diphenylamino)-phenyl)phenyl]-N-octyl-1,4-diketo-pyrrolo[3,4-c]pyrrole (TDP) was synthesized, and the one- and two-photon absorption and emission properties in the absence or presence of fluoride anion were investigated. The results show that TDP not only exhibits large two-photon absorption (2PA) cross section (δ) up to 1030 GM and strong red two-photon excitation fluorescence, but also could operate as one- and two-photon chemosensor selectively for fluoride anion. Interestingly, it is observed that both the detection sensitivity of TDP to fluoride anion and the ratiometric change in emission spectra upon two-photon induced by fluoride anion are higher than one-photon excitation, implying that TDP could serve better as two-photon fluorescence sensor for fluoride anion. The large δ and red-shifted 2PA band promoted by triphenylamine end-group enable TDP to sense fluoride anion under longer excitation wavelength and lower input laser power.