title: Thermochemistry of Oxo Transfer from Coordinated Nitrite in the Dinitro(5,10,15,20-tetrakis(o-pivalamidophenyl)porphinato)iron(III) Anion.
abstract: The thermochemistry of oxo transfer from coordinated nitrite in the dinitro(5,10,15,20-tetrakis(o-pivalamidophenyl)porphinato)iron(III) anion, ion-paired with the tetrapropylammonium ion, {[Fe(III)TpivPP(NO(2))(2)](-)Pr(4)N(+)}, has been evaluated in acetonitrile solution. This oxo-transfer half-reaction of {[Fe(III)TpivPP(NO(2))(2)](-)Pr(4)N(+)} has been assessed on the basis of the determination of the E(1/2) = +0.54 V vs SHE for the reversible [Fe(II/III)TpivPP(NO)(NO(2))](-)(/0) couple and the measurement of the formation constants for the association of NO and NO(2)(-) with the mononitroiron(III) porphyrin derivative. The formation constant for nitric oxide association, K(NO), has the value (1.21 +/- 0.08) x 10(3). The stability constant, K(2), for association of a second nitro ligand in 0.0100 M tetrapropylammonium perchlorate medium has been estimated as 2.18 x 10(3). The oxo-transfer half-reaction free energy, DeltaG degrees ((X/XO)), for addition of oxygen to [Fe(II)TpivPP(NO)(NO(2))](-) to form {[Fe(III)TpivPP(NO(2))(2)](-)Pr(4)N(+)} has been found to be -50 kJ/mol.
authors.affiliation: Collegium of Natural Sciences, Eckerd College, St. Petersburg, Florida 33733.
authors.forename: Melanie
authors.initials: M
authors.lastname: Frangione
authors.forename: Jennifer
authors.initials: J
authors.lastname: Port
authors.forename: Murtuza
authors.initials: M
authors.lastname: Baldiwala
authors.forename: Andrew
authors.initials: A
authors.lastname: Judd
authors.forename: John
authors.initials: J
authors.lastname: Galley
authors.forename: Magrey
authors.initials: M
authors.lastname: DeVega
authors.forename: Kara
authors.initials: K
authors.lastname: Linna
authors.forename: Leigh
authors.initials: L
authors.lastname: Caron
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Anderson
authors.forename: John A.
authors.initials: JA
authors.lastname: Goodwin