The challenging combination of intense fluorescence and high singlet oxygen quantum yield in photostable chlorins – a contribution to theranostics

High fluorescence quantum yields, high singlet oxygen quantum yields and intense absorptions in the phototherapeutic window are fundamental properties for compounds intended for fluorescence diagnosis and photodynamic therapy. We report on photostable chlorins that combine these properties. The fluorinated tetraphenylchlorin FCMet has Φ_F = 0.396 and Φ_Δ = 0.58 ± 0.07, whereas F₂CMet has Φ_F = 0.360 and Φ_Δ = 0.54 ± 0.05, and both have molar absorption coefficients larger than 30 000 M⁻¹ cm⁻¹ above 650 nm. These dual functional agents use nearly all the energy absorbed to perform the desired functions and are appropriate for theranostics applications.