ELECTRON-TRANSFER THERMODYNAMICS AND BONDING FOR THE SUPEROXIDE (O2.-), DIOXYGEN (.O2.), AND HYDROXYL (.OH) ADDUCTS OF (TETRAKIS(2,6-DICHLOROPHENYL)PORPHINATO)IRON, MANGANESE, AND COBALT IN DIMETHYLFORMAMIDE

The electrochemistry, spectroscopy, and magnetic moment of the superoxide ion adduct of (tetrakis(2,6-dichlorophenyl)porphinato)iron, (Cl8TPP)Fe(O2)-, and its Mn and Co analogues, (Cl8TPP)Mn(O2)- and (Cl8TPP)Co(O2)-, establish that their electron-transfer oxidations and reductions are dioxygen-centered rather than metal-centered. These O2*- adducts have a covalent bond that results from coupling between an unpaired d electron of the metal and an unpaired p electron of O2*-. The valence-electron hybridization for the iron atom in (Cl8TPP)Fe(O2)- is d5sp2 (three covalent iron bonds and 5 = 5/2), and the PFe-OO-(P = porphinato) covalent bond energy (ΔHDBE) is 20 kcal mol-1. Similar conclusions are made for the *O2* and *OH adducts for these metalloporphyrins. © 1990, American Chemical Society. All rights reserved.