Reaction of Ru 3(CO) 12 with ferrocenylacetylene. Crystal and molecular structure of Ru 2(CO) 6[C 4H 2(C 5H 4FeC 5H 5) 2

Abstract

The reaction of Ru 3(CO) 12 with ferrocenylacetylene FcCCH in refluxing hexane gives Ru 3(μ-H)(CO) 9(μ 3-η 2-CCFc) I, Ru 2(CO) 6[C 4H 2(Fc) 2] II and Ru 2(CO) 6[μ-C(H)C(Fc)COC(H)C(Fc)] III. Complexes I–III were characterized by IR and NMR spectroscopy, and II also by X-ray diffraction. Complex II crystallizes in the space group Cmc2 1 with a = 20.072(4), b = 14.322(2), c = 9.703(2) Å, and Z = 4. The structure was solved by the heavy-atom method and refined by least-squares analysis to R = 0.031 and R w = 0.037 for 1677 unique observed reflexions. Molecule II contains a ruthenacyclopentadiene ring, π-bonded to a Ru(CO) 3 group. The Ru 2(CO) 6 moiety adopts a “sawhorse” geometry, in contrast to the known structures of ruthenium complexes of this type, which have a “non-sawhorse” structure. Compound III possesses a nonsymmetrical diruthenacycloheptadienone moiety. The 1H NMR spectroscopy of III did not reveal any fluxionality of the “flyover” bridge leading to the exchange of σ- and π-bonds at two ruthenium atoms.