Enhancing the Stokes' shift of BODIPY dyes via through-bond energy transfer and its application for Fe3+-detection in live cell imaging

Two energy transfer cassettes that exhibit a large pseudo Stokes' shift (up to 400 nm) due to efficient through-bond energy transfer (up to 99%) have been constructed. Selective binding of Fe(III) with the donor entity significantly suppresses the excitation energy transfer resulting in fluorescence quenching in aqueous solution and in living cells.