Mononuclear and binuclear iron(III) complexes incorporating N4O3 coordinating heptadentate ligand: Synthesis, structure and magnetic properties

摘要

The N4O3 coordinating heptadentate ligand afforded the mononuclear [Fe-III(HL)][BPh4](1) and binuclear [(Fe2L)-L-III(OAc)(2)][BPh4] (2) complexes. In complex 1, the ligand binds in a trianionic N2O3 fashion whereas in the case of 2 the ligand binds in the trianionic N4O3 form in which the iron ions are held together by mu-phenoxo and bis mu-acetato bridges. In 1, the Fe(III) center has a trigonal bipyramidal geometry (tau = 0.84) whereas in 2 both the Fe(III) centers have a distorted octahedral geometry. Complex 2 shows an intramolecular weak antiferromagnetic interaction. Gas phase geometry optimizations have been performed using density functional theory without any symmetry constraints. The gas phase optimized structures agree well with the X-ray structure. (C) 2008 Elsevier Ltd. All rights reserved.