SYNTHESIS AND CHARACTERIZATION OF THE CATIONIC PORPHYRIN ETRAFLUORO-N,N,N-TRIMETHYL-4-ANILINIUMYL)PORPHYRIN

The cationic porphyrin etrafluoro-N,N,N-trimethyl-4-aniliniumyl)porphy rin 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 methylati on of the corresponding 5,6-tetrafluoro-N,N-dimethyl-4-anilinyl)porphy rin, M(TF4-DMAP), and have been characterized by NMR and UV-vis spectr oscopies 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 coordina ted 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 iodometha ne.