Study on four pyridine-based difluoroboron compounds for mechanofluorochromic behaviors, the ink-free writing and detection of latent fingerprints

Abstract

With the increasing demand for multifunctional aggregation-induced emission materials, four pyridine-based difluoroboron compounds (1, 2, 3, and 4) with the anthryl unit as an electron donor and difluoroboron moiety as the electron acceptor were designed and successfully synthesized. It found that four compounds displayed significantly intramolecular charge transfer characteristics and solvatochromism phenomena. The other compounds possessed mechanofluorochromic behaviors under external mechanical stimulation except compound 1, owing to its lesser change value of the dipole moment between the ground and excited states. More importantly, they exhibited potential application in the field of ink-free writing due to reversible mechanochromism during the grinding and fumigation process. Additionally, four compounds were used for detection of latent fingerprints on the glass surface due to their excellent aggregation effects in the THF/water mixtures. This research provides a reference for exploring multifunctional aggregation-induced emission difluoroboron compounds with brightness luminescence.