A hypochloritoiron(III) porphyrin species has been proposed as a key intermediate in an antimicrobial defense system in neutrophils and in heme-catalyzed chlorination reactions. We report herein the preparation, spectroscopic characterization, and reactivity of the bis(hypochlorito)iron(III) porphyrin complex [(TPFP)Fe(III)(OCl)(2)](-) (1) and the imidazole-hypochloritoiron complexes (TPFP)Fe(III)(OCl)(1-R-Im) [R = CH(3) (2), H (3), CH(2)CO(2)H (4)], in which TPFP is 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinate. The structures of 1-4 were confirmed by absorption, (2)H and (19)F NMR, EPR, and resonance Raman spectroscopy and electrospray ionization mass spectrometry at low temperature. The reactions of 1 and 2 with various organic substrates show that 1 and 2 are capable of chlorination, sulfoxidation, and epoxidation reactions and that 1 is much more reactive with these substrates than 2.