An NIR-emitting cyanine dye with pyridinium groups: the impact of regio-bond connection on the photophysical properties

Abstract

Two ESIPT-based isomeric cyanines were synthesized with significant bathochromic shift in the optical absorption λ_abs and emission λ_em, along with a very large Stokes shift. Probe 2 exhibited a longer conjugation and better photostability. Both compounds exhibited good selectivity for labeling the plasma membrane of prokaryotic cells and the hair cells of zebrafish.