Towards improved halogenated BODIPY photosensitizers: clues on structural designs and heavy atom substitution patterns.

The singlet oxygen (1O2) production quantum yield (ΦΔ) of 14 halogenated BODIPY dyes has been determined (0.01 < ΦΔ < 0.99). 1O2 production and photostability have been evaluated considering the BODIPY structure, the substitution pattern, and the number and type of heavy atoms and quenching rate constants of 1O2 by the sensitizer. In view of the experimental results and principal component analysis (PCA), guidelines for an improved design of efficient and photostable halo-BODIPY sensitizers are proposed.