Synthesis, characterization, and formation constant of hexacoordinate iron(III) complexes

Abstract

Twelve iron(III) complexes [Fe^III(L^X)₂]ClO₄, where (L^X)⁻ is the deprotonated form of a series of asymmetric ligands containing pyridine and substituted phenol moieties (XPh(OH)–CH=N–(CH₂) _n –Py that X = H, 5-Br, 5-NO₂, 5-OMe, 4-OMe, 3-OMe, and n = 1, 2), were synthesized and characterized by ¹H NMR, IR, UV-Vis spectroscopy, mass spectrometry, and elemental analysis. Formation constants were measured using UV-Vis spectrophotometric titration at constant ionic strength (0.10 M NaClO₄) at 25 (±0.1)°C. The trend of the complex formation of Fe(III) ion with a given tridentate ligand decreases as follows:

Keywords:

• Iron
• Schiff base
• Formation constant
• Tridentate ligand

Acknowledgement

We are grateful to Shiraz University Research Council for their financial support.