Cobalt dioxygen binding

Fig. 5. A restricted molecular orbital description of the essential spin pairing interaction involved in dioxygen binding to a cobalt (Il)-base (B) adduct. Reprinted with permission from Ref. 48. Copyright 1976 American Chemical Society.

FIGURE 4.7 Acyclic and macrocyclic polyamine ligands that support dioxygen binding cobalt complexes. 

Any adequate theoretical treatment must also explain how iron-porphyrin systems can bind not only O2, but also CO, NO, alkyl isocyanides, and alkyl-nitroso moieties. A simple qualitative model presented by Wayland and coworkersconveniently summarizes ligand-binding geometries of cobalt and iron porphyrins. Although a reasonable quantitative theoretical consensus exists for 1 1 cobalt-dioxygen species, the same cannot be said yet for iron-dioxygen systems. 

To demonstrate this concept, Krebs and Borovik [21] examined dioxygen binding to immobilized cobalt Schiflf base complexes. The kinetically inert six-coordinate 36 was immobilized into a methacrylate host according to Scheme 14. Complex 36... 

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