Pentadienyl Ligands in Cluster Complexes. Synthesis and Structural Characterization of Ru5(CO)12(μ4-S)(μ-H)(μ-1,5-Me2C5H5) and Ru6(CO)15(μ4-S)(μ-H)(μ-1,5-Me2C5H5)

Article abstract of DOI:10.1021/ja00229a023

The cluster complexes Ru5(CO)15(μ4-S) (1) and Ru6(CO)18(μ4-S) (2) react with trans-2-heptene to yield the new complexes Ru5(CO)12(μ4-S)(μ-H)(μ-1,5-Me2C5H5) (3) and Ru6(CO)15(μ4-S)(μ-H)(μ-1,5-Me2C5H5) (4) in the yields 4 percent and 7 percent, respectively.Better yields, 26 percent and 18 percent, respectively, were obtained by substituting 2,4-heptadiene for the trans-2-heptene.Both products were characterized by single-crystal X-ray diffraction analyses.For 3: space group, P2₁/n; a = 9.556(3), b = 17.878(6), c = 15.642(7) Angstroem; β = 98.54(3) degree; V = 2642(3) Angstroem³, Z = 4.The structure was solved by direct methods and was refined (3373 reflections) to the final residuals R =0.026 and R_w = 0.027.The molecule consists of a square-pyramidal cluster of five ruthenium atoms with a quadruply bridging sulfido ligand across the square base.An η⁵-1,5-dimethylpentadienyl ligand in an S-conformation bridges two of the meatl atoms in the square base, with three carbon atoms bonded to one metal atom and two to the other.A hydride ligand bridges one of the 3-fold faces of the cluster that is adjacent to the pentadienyl ligand.For 4: space group, P2₁/n; a = 8.311(2), b = 32.479(5), c = 11.491(1) Angstroem; β = 99.09(1) degree; V = 3063(1) Angstroem³; Z =4.The structure was solved by direct methods and refined (2905 reflections) to the final values of residuals, R = 0.030 and R_w = 0.030.The molecule consists of a square-pyramidal cluster of five ruthenium atoms, with a Ru(CO)4 group bridging one edge of the square base, and S-shaped 1,5-dimethylpentadienyl ligand across the basal edge opposite the Ru(CO)4 group, and a sulfido ligand across the square base.The hydride ligand bridges the triangular face that lies opposite of the pentadienyl ligand.The pentadienyl ligands in 3 and 4 were formed by an unusual process that involves the activation of an aliphatic C-H bond in the olefins.Compound 4 was also obtained from 3 in 37 percent yield by reaction with Ru(CO)5 at 80 deg C.Compound 3 was obtained from 4 in 30 percent yield by treatment with CO at 98 deg C.