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Synthesis and Properties of Dinuclear μ‐Oxodiiron(III) Complexes of Amide‐Based Macrocyclic Ligands
Author(s) -
Kumar Sushil,
Vaidya Shefali,
Pissas Michael,
Sanakis Yiannis,
Gupta Rajeev
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200683
Subject(s) - chemistry , amide , crystallography , magnetic susceptibility , ligand (biochemistry) , redox , mössbauer spectroscopy , antiferromagnetism , ion , stereochemistry , inorganic chemistry , organic chemistry , biochemistry , physics , receptor , condensed matter physics
We report the syntheses, structural, Mössbauer, magnetic, and redox characterization of a series of μ‐oxido‐bridged diiron(III) complexes in a set of 13‐membered amide‐based macrocyclic ligands that contain electron‐donating and ‐withdrawing substituents (–H, –Cl, and –CH 3 ) on the ligand periphery. For all three complexes, the Mössbauer spectra indicate that two iron sites are indistinguishable, a fact that is well supported by X‐ray crystallographic results. The three complexes exhibit almost identical isomer shifts but distinctively different quadruple splitting values. The variable‐temperature magnetic susceptibility measurements show that the unsupported single μ‐oxido group mediates a strong antiferromagnetic coupling between two Fe III ions. The three diiron complexes show quite different magnetic coupling ( J = 191, 194, and 230 cm –1 , respectively; H iso = J S 1 · S 2 ) that has been related to the structural differences. We also show that the electron‐donating and ‐withdrawing substituents present on the ligands influence the redox properties.