Iron complexes porphyrin dioxygen complex

Electrochemical reduction of 7 iron porphyrin dioxygen complexes leads to a species identified as [Fe(III)(porph)02 ] This species has also been reported to be formed on addition of superoxide to [Fe(porph)] ... 

Gerothanassis, I. R, Momenteau, M. (1987). NMR spectroscopy as a tool for studying synthetic oxygen carriers related to biological systems Application to a synthetic single-face hindered iron porphyrin-dioxygen complex in solution, J. Am. Chem. Soc., 109 6944. 

Other aspects of solvation have included the use of surfactants (SDS, CTAB, Triton X-100), sometimes in pyridine-containing solution, to solubilize and de-aggregate hemes, i.e., to dissolve them in water (see porphyrin complexes, Section 5.4.3.7.2). An example is provided by the solubilization of an iron-copper diporphyrin to permit a study of its reactions with dioxygen and with carbon monoxide in an aqueous environment. Iron complexes have provided the lipophilic and hydrophilic components in the bifunctional phase transfer catalysts [Fe(diimine)2Cl2]Cl and [EtsBzNJpeCU], respectively. 

The kinetics and mechanism for oxygen transfer between 4-cyano-V,V,-dimethylaniline V-oxide and a C2-capped mexo-tetraphenylporphyrinatoiron(III) and mc5 o-tetrakis(pentafiuorophenyl)-porphyrinatoiron(III) have been established. Addition of a copper(II) porphyrin cap to an iron(II)-porphyrin complex has the expected effect of reducing both the affinities and rate constants for addition of dioxygen or carbon monoxide. These systems were studied for tetradecyl-substituted derivatives solubilized by surfactants such as poly(ethylene oxide) octaphenyl ether. ... 

Scheme 6. The reaction of iron(II) porphyrins with dioxygen in the presence of a reducing agent to produce verdoheme (top right) and a biliverdin-type complex (bottom right).

Many of the structurally characterized -superoxo complexes are cobalt containing, or are iron complexes with sterically hindering porphyrins. Co compounds often react with dioxygen to form mononuclear superoxo complexes. 

Although many interesting iron(II) porphyrin complexes have been synthesized that bind dioxygen reversibly, they are not suitable for achieving the cooperative O2 binding profile of hemoglobin or myoglobin. However, entirely synthetic... 

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