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)Cl-2 (L-1=1,3-bis[N-(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) angstrom, V = 6168.9(6)angstrom(3), Z = 8, D-cal = 1.951 Mg/m(3). 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) angstrom. 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.