Iron complexes of derivatised pentadentate macrocyclic ligands; the crystal and molecular structure of dichloro(6,13-(bis-2-hydroxyethyl)-6H, 13H-tripyrido[cd,fg,lm] [1,2,4,7,9,10,13] heptaaza-pent adecine)iron (III) chloride

Iron(II) complexes of planar pentadentate macrocyclic ligands containing 2,2'-bipyridine or 1,10- phenanthroline subunits have been prepared by template condensation of open-chain bis(hydrazines) with 2,6-diacetylpyridine or 2,6-pyridinedialdehyde. The complexes are seven-coordinate trigonal bi- pyramidal iron(II) complexes containing two axial ligands. Aerial oxidation yields iron(III) complexes, which may not be prepared directly by template condensations. The seven-coordinate iron(III) complex [FeL₄Cl₂]Cl has been structurally characterised (crystallographic data: space group Pna2₁, a=15.494(8), b=12.873(6), c=12.229(6) Å, Z=4, 4487 reflections with F≥3σ(F), R=0.0770).