Dioxygen Reactivity of Reduced Heme and Heme-Copper Complexes Utilizing Tetraarylporphyrinates Tethered with Both a Pyridyl Axial Ligand and N,N-Bis[2-(2-pyridyl)ethyl]amine Chelate.

New heterobinucleating ligands for heme−Cu O2-reactivity studies feature a variably appended tridentate chelate {N,N-bis[2-(2-pyridyl)ethyl]amine} possessing an already established copper(I)/O2 chemistry. Reduced metal complexes have been synthesized and characterized. (3L)FeII (1a), a heme−Fe(II) empty-tether complex, binds O2 reversibly. Heme−Cu complex [(4L)FeIICuI]+ (2b) forms a peroxo level adduct [(4L)Fe−O2−Cu]+ (4b).