Crystal structure and magneto-structural investigation of alkoxido bridged dinuclear Fe(III) complexes with 1,3-oxazolidine ligands

摘要

Four 1,3-oxazolidine based ligands (H2L1-H2L4) were synthesized in solvent-free condition from the reaction of amino alcohols (2-amino-2-(hydroxymethyl)-1,3-propanediol or 2-amino-2-ethy1-1,3-propanediol) and 2-acetylpyridine or 2-pyridinecarboxaldehyde at 110 T. Four new dinuclear Fe(III) complexes, [Fe-2(HL1)(N-3)(4)] (1), EFe2(HL2)(N-3)(4)] (2), [Fe-2(HL3)(N-3)(4)] (3) and [Fe-2(HL4)(N-3)(4)] (4), were synthesized with a similar procedure by the reaction of H2L1-4, Fe(NO3)(3).9H(2)O and NaN3 in 1:1:2 molar ratios in methanol. The ligands and complexes were characterized by elemental analysis and spectroscopic methods. The structure of complexes was solved by single-crystal X-ray diffraction analysis which showed complexes 1-4 to be alkoxido-bridged dinuclear Fe(III) complexes. The structural studies indicated that the crystal structure of 2, 3 and 4 consist of a centrosymmetric dinuclear Fe(III) complexes while the asymmetric unit in 1 consists of two halves of the two independent molecules. The Fe(III) ions have similar coordination environments (cis-FeN4O2) in all of 1-4 which can be described as distorted octahedral geometry. The 1,3-oxazolidine ligands act as mononegative tridentate N2O-donor ligand in 1-4. Two azide groups are also coordinated to each Fe(III) ion as terminal monodentate ligands. The alcoholic arms of the 1,3-oxazilidine ligands act as bridging groups between Fe(III) ions and the Fe center dot center dot center dot Fe distances through these bridges are in the range of 3.157-3.198 A. Magnetic studies in 2-300 K range reveal antiferromagnetic interactions between the Fe(III) ions with values for the magnetic coupling constants in the range -9.4 cm(-1) to -9.7 cm(-1), with H =-2(f)(S1S2) (C) 2019 Elsevier Ltd. All rights reserved.