Synthesis and X-Ray Crystal Structure of [(thf)4Ca{Fe2(CO)6(μ-CO)(μ-PPh2)}2]

The reactions of [(thf)4ca(pph2)2] with the iron carbonyls fe2(co)9 and fe3(co)12 in thf yield mixtures of iron carbonyl-containing phosphanides which transform upon prolonged heating into [(thf)4ca{fe2(co)6(μ-co)(μ-pph2)}2] (1) with a chemical shift of δ(31p) = 127.9 ppm. the distorted octahedrally coordinated calcium atom binds to four thf molecules (av. ca-o 234.0 pm) and the bridging carbonyl ligand of the complex anions {fe2(co)6(μ-co)(μ-pph2)}-[ca-o 229.8(4), fe-fe 257.9(2) pm].