Fe2(μ-E2)(CO)6 (E = S, Se, and Te) as Reagents for the Preparation of Mixed-Metal Chalcogenide Clusters

Article abstract of DOI:10.1021/ja00369a024

The compounds Fe2(μ-E2)(CO)6, where E = S, Se, and Te, react efficiently with Pt(PPh3)2C2H4 to afford the new heterometallic clusters, (CO)6Fe2(μ-E)2Pt(PPh3)2.This reaction formally involves the homolytic cleavage of the E-E bond in the μ-E2 precursor complexes and represents a novel route to mixed-metal clusters. 13P NMR of (PPh3)(CO)5Fe2(μ-S)2Pt(PPH3)2 (prepared from Fe2(μ-S2)(CO)5(PPh3) indicates that the plane of the Pt coordination sphere is perpendicular to the iron-iron vector.The structure of (CO)6Fe2(μ3-Se)2Pt(PPh3)2 was determined by conventional X-ray crystallographic techniques.The crystals were monoclinic with a = 10.944(2) Angstroem, b = 16.321(3) Angstroem, c = 23.135(4) Angstroem, β = 94.68(1) deg, Z = 4; the space group is P2₁/n.Conventional full-matrix least-squares refinement with nonhydrogen atoms anisotropic and fixed hydrogen atoms isotropic gave R₁ = 0.037 and R₂ = 0.040 for 7119 reflections having 2θ Mo Kα/ < 58.7 deg and I > 3?(I).The structure consists of an isosceles triangle of metal atoms tethered by two capping μ3-Se moieties.The two Fe(CO)3 units are mutually bonded, and this fragment closely resembles Fe2(μ-Se2)(CO)6 with an expanded Se-Se vector.We reconcile the reactivity of these μ-E2 compounds and the chemical dormancy of species such as Ph2Te2 and monometallic S2 complexes as being both electronic and steric (ring strain) in origin.