Synthesis and characterization of a new unsymmetrical μ-oxo-bridged iron(III) complex with triphenylarsine oxide ligands

A new unsymmetrical ore-bridged complex [Fe2O(OAsPh3)(4)Cl-3] [FeCl4] . CH3CN was synthesized and characterized by X-ray structural analysis, elemental analysis, spectral and magnetic data. The compound crystallizes in a monoclinic system, space group P2(1)/c, with a = 13.77(1), b = 21.50(2), c = 25.62(2) Angstrom, beta = 90.22(7)degrees, and Z = 4 (R = 0.0335 for 5859 independent reflections with I>3 sigma(I)). Crystal structure analysis revealed that one iron atom is pentacoordinated by four triphenylarsine oxide ligands and a mu-oxo ligand which connects a tetracoordinated iron atom with the chromophore FeCl3O. The magnetic properties of the complex were investigated in the 4.2-300 K temperature range and these data correspond to the electron paramagnetic resonance spectra. (C) 1998 Elsevier Science S.A. All rights reserved.