Synthesis and characterization of a tris(2-hydroxyphenyl)methane-based cryptand and its triiron(iii) complex

Reaction of tris(5-amino-2-ethoxy-3-isopropylphenyl)methane and pyridine-2,6-dicarbonyl-dichloride affords a multi-dentate cryptand in 48% yield. Metallation with iron(III) chloride results in a substantial conformational change of this ligand to give a trianionic triiron(III) complex. Ferric cations line the periphery of the internal cavity with each adopting a square pyramidal N(3)Cl(2) coordination environment.