Molybdenum and tungsten complexes with carbon dioxide and ethylene ligands

The first examples of stable metal complexes with coordinated ethylene and carbon dioxide ligands are reported. Reaction of tris(ethylene) complexes mer-M(C(2)H(4))(3)(PNP) (M = Mo and W; PNP = 2,6-bis(diphenylphosphinomethyl)pyridine) with CO(2) yields the corresponding, mixed cis-M(C(2)H(4))(2)(CO(2))(PNP) derivatives. X-ray studies reveal six-coordinate structures exhibiting η(2)-ethylene and κ(2)-C,O carbon dioxide coordination. Remarkably, the formation of the molybdenum CO(2) adduct occurs also in the solid state at room temperature, under 4 bar of CO(2), in a nearly quantitative manner.