Facile Synthesis of meso-Tetrakis(perfluoroalkyl)porphyrins: Spectroscopic Properties and X-ray Crystal Structure of Highly Electron-Deficient 5,10,15,20-Tetrakis(heptafluoropropyl)porphyrin

The synthesis, structure, optical spectrum, and electrochemistry of 5,10,15,20-tetrakis(perfluoropropyl)porphyrin, 1, are reported. The high yield preparative method, starting from (hydroxymethyl)pyrrole precursors such as 2,2,3,3,4,4,4-heptafluoro-1-(2-pyrrolyl)-1-butanol, 2, is general for a wide variety of meso-perfluoroalkyl-substituted porphyrins. The X-ray crystal structure of 1 is noteworthy in that it shows a S₄-distorted porphyrin core that appears to derive from an unusual hydrogen bonding interaction between a fluorocarbon fluorine atom and a porphyrin NH proton. A comparison of the electrochemical properties of the zinc derivative of 1 with those of [5,10,15,20-tetrakis(pentafluorophenyl)-2,3,7,8,12,13,17,18-octabromoporphinato]zinc(II) indicates that meso-perfluoroalkylated porphyrins are among the most electron-deficient porphyrin ligands known. meso-Tetrakis(perfluoroalkyl)porphyrins and their elaborated derivatives, with their unusual electronic properties, should thus serve as useful ligands for a variety of catalytic and stoichiometric transition metal-mediated redox reactions.