Abstract
Following up on the characterization of a new (heme)Fe(III)-superoxide species formed from the cryogenic oxygenation of a ferrous-heme (P(Py))Fe(II) (1) (P(Py) = a tetraarylporphyrinate with a covalently tethered pyridine group as a potential axial base), giving (P(Py))Fe(III)-O(2)(•-) (2) (Li Y et al., Polyhedron 2013; 58: 60-64), we report here on (i) its use in forming a cytochrome c oxidase (CcO) model compound, or (ii) in a reaction with nitrogen monoxide (•NO; nitric oxide) to mimic nitric oxide dioxygenase (NOD) chemistry. Reaction of (2) with the cuprous chelate [Cu(I)(AN)][B(C(6)F(5))(4)] (AN = bis[3-(dimethylamino) propyl]amine) gives a meta-stable product [(P(Py))Fe(III)-([Formula: see text])-Cu(II)(AN)][B(C(6)F(5))4] (3a), possessing a high-spin iron(III) and Cu(II) side-on bridged peroxo moiety with a μ-η(2):η(2)-binding motif. This complex thermally decays to a corresponding μ-oxo complex [(P(Py))Fe(III)-(O(2-))-Cu(II)(AN)][B(C(6)F(5))4] (3). Both (3) and (3a) have been characterized by UV-vis, (2)H NMR and EPR spectroscopies. When (2) is exposed to •NO((g)), a ferric heme nitrato compound forms; if 2,4-di-tert-butylphenol is added prior to •NO((g)) exposure, phenol ortho-nitration occurs with the iron product being the ferric hydroxide complex (P(Py)) Fe(III)(OH) (5). The latter reactions mimic the action of NOD's.