Oxazepines are unsaturated seven-membered heterocyles containing an oxygen and a nitrogen. It has been reported that some oxazepines show interesting biological activities such as antitumor, anti-inflammation, antimicrobiotic acitivites. Especially, medicinally important drugs including Amoxapine, Loxapine, and Nitroxazepine have distinctive structural features consisting of oxazepine backbone with hybridization of two benzene rings.
In this work, we developed a new donor–acceptor type napthalene-based oxazepine fluoropore, OXN-1, which exhibits high chemcial stability in harsh conditions. Its exceptional structural stabilities and photophysical properties were thoroughly examined and further explained by quantum chemical calculations. Its bioimaging capabilities for cells with low cytotoxicity were verified. In addition, its deep tissue imaging capability with two-photon microscopy (TPM) was evaluated. These findings may present OXN-1 as a new promising fluorescent probe in biomedicinal application.