Synthesis,crystal structure,magnetic characterization and spectroscopic properties of a new dinuclear iron(III) complex asymmetrically bridged by a phenoxo and methoxo groups

Dinuclear iron(III) derivative of Fe₂L¹(OCH₃)Cl₂ (L¹=1,3‐bisN‐(5‐bromo‐2‐hydroxybenzylidene)‐2‐aminoethyl]‐2‐(5‐bromo‐2‐hydroxyphenyl)imidazolidine) has been synthesized, its crystal structure determined and magnetically characterized. The title compound crystallizes in orthorhombic space group Pbcn with cell parameters a = 12.9770(10), 18.7930(10), 25.2950(10) Å, V = 6168.9(6)ų, Z = 8, D_cal = 1.951 Mg/m³. The two iron(III) ions are asymmetrically bridged by a phenoxo and methoxo groups in the compound. The iron(III) centers are separated by 3.166(3) Å. Magnetic susceptibilities of the complex were measured over the range 5 – 298 K and the observed data were successfully simulated by the equation based on the spin‐Hamiltonian operator. Magnetic susceptibility measurements indicate very weak antiferromagnetic coupling between the iron(III) ions with J = – 11.5 cm^‐1. The comparison of the magnetic and structural parameters of the investigated compound is given and the nature of the magnetic super‐exchange interaction of the title compound is compared with similar dinuclear iron(III) complexes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)