Single-Benzene-Based Clickable Fluorophores for In Vitro and In Vivo Bioimaging.

A series of miniaturized, clickable single-benzene-based fluorophores derived from tetrafluoroterephthalonitrile is reported. Fluorophores based on a tetrahydroquinoxaline skeleton exhibited improved photophysical properties due to enhanced electron delocalization between donor and acceptor groups compared to those with a dihydro[1,4]thiazine skeleton. These easily synthesized clickable fluorophores were successfully applied in both in vitro and in vivo bioimaging following protein conjugation.