Sterically hindered benzoates: A synthetic strategy for modeling dioxygen activation at diiron active sites in proteins

Bulky terphenyl carboxylates and related benzylsubstituted benzoates have been used to assemble a variety of new diiron complexes analogous to nonheme diiron protein active sites. Through this conceptually simple approach, novel biomimetic structures have been accessed and biologically relevant oxidized intermediates and products have been isolated and characterized by both spectroscopic and X-ray crystallographic methods. Interesting similarities and differences in the observed chemistry of the iron(n) complexes, including ligand substitution and dioxygen activation reactions, result from variation of the specific carboxylate and accompanying N-donor ligand structures. As a result, new insights have been obtained into structure/function relationships in carboxylate-rich nonheme diiron proteins.