Iron(III) complexes of pyridine-based tetradentate aminophenol ligands as structural model complexes for the catechol-bound intermediate of catechol dioxygenases

Some pyridine-based tetradentate aminophenol ligands and their acetylacetonato iron(III) LFe(acac) complexes have been synthesized and characterized by spectroscopic techniques, cyclic voltammetry, single crystal X-ray diffraction and magnetic susceptibility studies. X-ray analysis revealed monomer complexes in which the iron centers have been surrounded by pairs of acetyl acetonate and phenolate oxygens and two nitrogen atoms of the ligands. It has been shown that the two Fe–Oacac bonds in these complexes are not equal, as seen for Fe–Ocat bonds in the catechol-bounded intermediate of catechol dioxygenases. Variable temperature magnetic susceptibility indicates a paramagnetic behavior for all the mononuclear high spin iron complexes. The investigated complexes undergo electrochemical oxidation and reduction.

Graphical abstractSome new pyridine-based tetradentate aminophenol ligands and their acetylacetonato iron(III) complexes have been synthesized and characterized by spectroscopic techniques, cyclic voltammetry, single crystal X-ray diffraction and magnetic susceptibility studies.Figure optionsDownload full-size imageDownload as PowerPoint slide