Fluorescence Photoactivation by Ligand Exchange around the Boron Center of a BODIPY Chromophore

Chelation of the boron center of the borondipyrromethene (BODIPY) platform by a catecholate ligand results In effective fluorescence suppression. Electron transfer from the chelating unit to the adjacent chromophore upon excitation Is responsible for fluorescence quenching. Under the influence of a photoacid generator, the catecholate chelator can be exchanged with a pair of methoxide ligands. This photoinduced transformation prevents electron transfer and efficiently activates the fluorescence of the BODIPY chromophore.