A magnetostructural study of three novel iron(III) complexes of tripodal amine phenolate ligands

Three new iron(III) aminophenolate complexes, namely LtriFe(CH3OH), L2OHFe2 and L2OMeFe2(μ-OH)2, were synthesized. L represents the deprotonated forms of NR2X, where NR2 stands for the bis(2-hydroxy-3,5-di-tert-butylbenzyl)amine, basic motive and X is 2-hydroxy-3,5-di-tert-butylbenzyl in Ltri, 2-hydroxyethyl in LOH, 2-methoxyethyl in LOMe. The complexes were characterized by X-ray, IR- and UV–Vis spectroscopies and magnetic susceptibility studies. LtriFe(CH3OH) has a distorted trigonal bipyramidal geometry in which three phenolate oxygen atoms, the amine nitrogen atom of the ligand and a methanol molecule are coordinated to the iron center. LOH2Fe2 and L2OMeFe2(μ-OH)2 show a dimeric structure in which the iron centers are surrounded by the amine nitrogen atom, two phenolate groups and two bridging alkoxo or hydroxo groups, which originate from the alkanole arm of LOH in LOH2Fe2 or water in L2OMeFe2(μ-OH)2. ic susceptibility measurements indicate moderate antiferromagnetic coupling between the two iron centers in LOH2Fe2 and L2OMeFe2(μ-OH)2 whilst the complex LtriFe(CH3OH) was paramagnetic.