SYNTHESIS AND CHARACTERIZATION OF SOME REVERSIBLE IRON(II) DIOXYGEN CARRIERS OF LACUNAR MACROBICYCLIC LIGANDS AND THEIR REACTIVITIES WITH DIOXYGEN.

Article abstract of DOI:10.1021/ja00360a008

The preparation of a new family of iron(II) complexes with macrobicyclic ligands is described. These complexes contain a persistent protected void (lacuna) in the vicinity of one of the axial ligation sites of the metal ion, as shown by two X-ray crystal structures. Both structures confirm the presence of a lacuna but of dramatically different shape and steric requirements. This cavity may accommodate a small ligand such as dioxygen, and in favorable cases the complex can react reversibly with O//2 to produce dioxygen-carrying behavior. The oxygen-binding behaviors of a large number of the iron(II) species have been investigated spectrophotometrically.