Synthesis and characterization of new coumarin-based COUPY fluorophores

Abstract

The availability of fluorophores based on small organic molecules operating in the optical window of biological tissues enables the precise interrogation of biochemical and biological systems. Among coumarin-based fluorophores, COUPY dyes are particularly interesting for developing novel cellular and molecular imaging tools due to their promising physicochemical and photophysical properties, such as excellent cell permeability, large Stokes’ shifts, high photostability and absorption and emission in the far-red/near-infrared (NIR) region, the latter being important to minimize photodamage to living cells. In this work, we have focused on the synthesis and characterization of four new COUPY dyes with the aim of improving their photophysical properties as well as to allow the labelling of targeting ligands by incorporating suitable functional groups within the coumarin scaffold.