Inorganic Chemistry, Vol.33, No.14, 3159-3163, 1994
Synthesis and Characterization of the Cationic Porphyrin Meso-Tetrakis(2,3,5,6-Tetrafluoro-N,N,N-Trimethyl-4-Aniliniumyl)Porphyrin
The cationic porphyrin meso-tetrakis(2,3,5,6-tetrafluoro-N,N,N-trimethyl-4-aniliniumyl)porphyrin and its metal complexes, M(TF4TMAP)n+ (M = H-2, Ni(II), Co(II), n = 4; M = Co(III), Fe(III), n = 5), have been synthesized via methylation of the corresponding meso-tetrakis(2,3,5,6-tetrafluoro-N,N-dimethyl-4-anilinyl)porphyrin, M(TF4-DMAP), and have been characterized by NMR and UV-vis spectroscopies and electrochemistry. These porphyrins have redox potentials which are very similar to those of the cationic porphyrins M(TNMePyP)n+ but have less tendency to dimerize or adsorb onto surfaces. Fe(III)(TF4TMAP)5+ is monomeric in aqueous solution, with a pK(a) for coordinated water of 6.0 (mu 0.1). None of the water-soluble cobalt and nickel porphyrins studied could electrocatalyze the reduction of protons to H-2 at pH > 4, but they did react with electrophiles such as iodomethane.
Keywords:SOLUBLE IRON(III) PORPHYRIN;AQUEOUS-SOLUTION;SPECTROSCOPIC CHARACTERIZATION;ELECTROCATALYTIC REDUCTION;RESONANCE SPECTROSCOPY;HYDROGEN-PEROXIDE;KINETIC ASPECTS;WATER;IRON;TETRAPHENYLPORPHYRIN