Complexes of Iron (II) and Iron (III) with the Tetradentate Macrocycle 5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene

Abstract

A series of iron complexes of the cyclic ligand 5,7,7,12,14,4-hexamethyl-l,4,8,ll-tetraazacyclo-tetradeca-4,11 -diene, [14]dieneN4, have been isolated. The coordination number and spin state of the metal atom are dependent on the axial ligands. High-spin, five-coordinate iron(II) complexes were isolated when weak axial ligands were present and low-spin, six-coordinate complexes were isolated with strong axial ligands. One complex has a moment intermediate between the high-spin and low-spin values and has been shown to exist in spin-state equilibrium by the study of the temperature dependence of the magnetic suscepttbility. The iron(II) complexes can be oxidized, yielding low-spin, six-coordinate iron(III) complexes. © 1972, American Chemical Society. All rights reserved.