Neutral diiron(III) complexes with Fe₂(μ-E)₂ (E = O, S, Se) core structures: reactivity of an iron(I) dimer towards chalcogens.

Three neutral bis(μ-chalcogenido)diiron(III) complexes, [{(N,N'-Pipiso)Fe(μ-E)}2] (Pipiso(-) = [(DipN)2C(cis-2,6-Me2NC5H8)](-), (Dip = C6H3Pr(I)2-2,6; E = O, S or Se) have been prepared by reactions of the iron(I) dimer [{(μ-N,N'-Pipiso)Fe}2] with O2, S8 or Se∞. Treating the μ-selenido compound [{(N,N'-Pipiso)Fe(μ-Se)}2] with O2 cleanly generated its μ-oxo counterpart, [{(N,N'-Pipiso)Fe(μ-O)}2]. X-ray crystallographic analyses of the compounds showed them to possess Fe2(μ-E)2 core structures with distorted square planar (E = O) or tetrahedral (E = S or Se) iron coordination geometries. Magnetic, (57)Fe Mössbauer spectroscopic and computational studies indicate medium to strong antiferromagnetic coupling between the two high-spin Fe(III) ions in all three compounds.