A Synthetic Strategy for the Structural Modification of Photoactivatable BODIPY-Oxazine Dyads

Strategies to regulate the ability of photoactivatable fluorophores to absorb activating photons are essential to allow their operation under illumination conditions compatible with biological samples. In this context, our laboratories identified a viable synthetic protocol to introduce a conjugated substituent on the photocleavable component of a BODIPY-oxazine dyad and enhance its molar absorption coefficient at the activation wavelength. This structural transformation translates into a four-fold absorbance increase in the spectral window appropriate for photoactivation and does not prevent the photochemical transformation. Indeed, the photoinduced cleavage of the oxazine component occurs in organic solvents, aqueous solutions and hydrogel matrices with a concomitant bathochromic shift in BODIPY emission. These results demonstrate that the photophysical properties of this family of BODIPY-oxazine dyads can be manipulated with the aid of chemical synthesis without suppressing their photochemical behavior.