Synthesis and Electrochemistry of Free-Base Porphyrins Bearing Trifluoromethyl meso-Substituents

Our article is available to read at ChemElectroChem.

CF₃-substituted porphyrins have attracted increasing interest over the past decade. However, the number of examples reported in the literature remains quite limited and much remains to be done to understand the properties and reactivity of these molecules. We are now reporting on the synthesis of a series of free base porphyrins incorporating one, two and three CF₃ substituents, including the 5,10,15-tris(CF₃) substituted porphyrin which has never been described before. We have also carried out detailed electrochemical and spectroscopic analyses aiming at assessing the electron-withdrawing properties of the CF₃ substituents compared to the widely used C₆F₅. Our studies led us to propose an interpretation of the quite unusual electrochemical signature of these molecules featuring three successive one-electron reduction waves.