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(μ3-E)2Pt(PPh 3)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. 31P NMR of (PPh3)(CO)5Fe2(μ3-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(PPh 3)2 was determined by conventional X-ray crystallographic techniques. The crystals were monoclinic with a = 10.944 (2) Å, b = 16.321 (3) Å, c = 23.135 (4) Å, β = 94.68 (1)°, 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 Kᾱ < 58.7° and I > 3σ(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.
ASJC Scopus subject areas
- Colloid and Surface Chemistry