Rational design of state-depending photoactivatable and photoconvertible fluorescent AIEgens through a rapid photocyclodehydrogenation reaction

Abstract

Photosensitive fluorophores have grand value and bright prospective in diverse photo-controlled applications including super-resolution imaging and advanced patterning; however, photoactivatable and photoconvertible small fluorophores encounter great challenges in comparison to their fast-growing protein-based counterparts. Herein, we proposed a general design strategy to achieve state-depending photoactivatable and photoconvertible fluorophores based on an AIE-active molecular skeleton through introducing a dipyridinylethene unit which easily undergoes a rapid photocyclodehydrogenation reaction. It is found that introducing a photoactive dipyrinylethene unit into an AIE-active tetraarylethene molecule can effectively regulate its dominant photophysical emission and photochemical reaction in a controllable way, and these combined compounds show predominant aggregation-induced emission properties in solid state but exhibit dominant photoactivatable and photoconvertible fluorescence behaviours in dispersed state. The photoactivatable and photoconvertible fluorescence is attributed to the rapid photo-induced cyclodehyrogenation reaction and AIE nature of the species involved in the photochemical processes. These findings outline a general design strategy to achieve photoactivatable and photoconvertible fluorescence systems by introducing a specific subunit easily undergoing rapid and efficient photocyclodehyrogenation reaction, and demonstrate exciting use of these state-dependent photosensitive fluorophores in diverse photo-controlled practical applications.