High valent transition metal chemistry. Synthesis and characterization of an intermediate-spin iron(IV) complex of a strong pi-acid ligand

A study was done on the synthesis of an intermediate-spin iron(IV) complex of a strong pi-acid ligand. It was shown that the geometry around the iron atom of Fe(eta4-1)(CNtBu) is an axially distorted octahedron. The average Fe-C distance is 1.969 angstroms while the average Fe-N distance is 1.910 angstroms. A study of the iron-isocyanide complexes show that the pi-acid character of the isocyanides is not strongly expressed.