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Lewis acid catalyzed condensation of pyrrole and 4-fluoro-2,6-dimethylbenzaldehyde followed by chemical oxidation afforded the corresponding chlorin along with the parent porphyrin. The subsequent metalation of the porphyrin-chlorin mixture in the presence of Zn(OAc)₂•2H₂O afforded Zn monoand di-hydroxychlorins in addition to the Zn porphyrin in a one-flask synthesis. This new direct hydroxylation reaction eliminates the need for highly toxic OsO₄and H₂S that are traditionally used for the generation of hydroxy chlorins. In addition to the full characterization of the zinc chlorins, we present cyclic voltammograms, steady-state absorption, and emission profiles of this rarely available class of compounds. Our findings show that Zn mono- and di-hydroxychlorins are stable compounds that possess exceptionally long triplet excited states in solution, making them promising candidates for photodynamic therapy. 

Molecular Ag(II) complexes are superoxidizing photoredox catalysts capable of generating radicals from redox-reticent substrates. In this work, we exploited the electrophilicity of Ag(II) centers in [Ag(bpy)₂(TFA)][OTf] and Ag(bpy)(TFA)₂(bpy, 2,2′-bipyridine; OTf, CF₃SO₃^–) complexes to activate trifluoroacetate (TFA) by visible light–induced homolysis. The resulting trifluoromethyl radicals may react with a variety of arenes to forge C(sp²)–CF₃bonds. This methodology is general and extends to other perfluoroalkyl carboxylates of higher chain length (R_FCO₂^–; R_F, CF₂CF₃or CF₂CF₂CF₃). The photoredox reaction may be rendered electrophotocatalytic by regenerating the Ag(II) complexes electrochemically during irradiation. Electrophotocatalytic perfluoroalkylation of arenes at turnover numbers exceeding 20 was accomplished by photoexciting the Ag(II)–TFA ligand-to-metal charge transfer (LMCT) state, followed by electrochemical reoxidation of the Ag(I) photoproduct back to the Ag(II) photoreactant. 

The compound [5,10,15,20-tetrakis(4-fluoro-2,6-dimethylphenyl)porphyrinato]platinum(II), [Pt(C₅₂H₄₀F₄N₄)] or Pt(II)TFP, has been synthesized and structurally characterized by single-crystal X-ray crystallography. The Pt porphyrin exhibits a long-lived phosphorescent excited state (τ₀ = 66 µs), which has been characterized by transient absorption and emission spectroscopy. The phosphorescence is extremely sensitive to oxygen, as reflected by a quenching rate constant of 5.0 × 10⁸ M⁻¹ s⁻¹, and as measured by Stern–Volmer quenching analysis. 

Mono-hydroxychlorins are uncommon macrocycles that have only been synthetically realized by modifying porphyrin rings using the harsh oxidizing agent OsO₄. We show here that a more directed delivery of the mono-hydroxychlorin may be concomitantly obtained from the oxidation of porphyrinogen using the mild conditions of the high dilution Lindsey porphyrin forming reaction where water content is minimized by using dry CHCl₃within the environment of a glovebox. We now report the direct synthesis of 17,18-dihydro-18-hydroxy-5,10,15,20-tetrakis-(4-fluoro,2,6-dimethylphenyl)-porphyrin (2H-TFChl-[Formula: see text]OH) together with the corresponding freebase porphyrin TFP. The TFP has been metalated with FeBr₂and MgBr₂•OEt₂resulting in metalloporphyrins Fe(III)TFP(Cl) and Mg(II)-TFP which have been structurally characterized by single-crystal X-ray crystallography. We find that the excited state properties of the mono-hydroxychlorin are similar to that of its parent TFP and Mg(II)TFP porphyrin congeners. Excited state deactivation by vibronic coupling to the high energy O-H oscillator is circumvented with the hydroxyl group remote to the 18[Formula: see text]-electron framework of the chlorin ring. These results reveal that strong H-bonding groups may be introduced on the periphery of the chlorin ring while maintaining the light-gathering properties that lie at the heart of photosynthesis of the chlorin ring.