DIMERIZATION OF ISOPROPENYLACETYLENE ON RU3(CO)12 - SYNTHESIS AND CRYSTAL-STRUCTURE OF RU3(CO)8(C10H12)

The new complex Ru3(CO)8(C10H12) has been synthesized by reacting Ru3(CO)12 and isopropenylacetylene in hydrocarbon solvents. It has been characterized by means of elemental analysis, i.r. and mass spectra; the crystal structure has been determined by X-ray methods. Crystals are triclinic, space group P1 with Z = 2 in a unit cell of dimensions a = 8.877(8), b = 13.594(10), c = 8.849(7) Å, α = 92.01(8), β = 98.41(8), γ = 106.13(7)°. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least squares to R = 0.028 for 4462 observed reflections. The complex is formed by a closed tri-metal atom cluster, bonded to eight carbonyls, two of which very asymmetrically bridging two metals, and to a six-carbon atom chain through σ and η-bonds. This chain, derived from the dimerization of two molecules of isopropenylacetylene, presents an extensive bond delocalization, as two triple bonds and one double bond of an isopropenyl group are involved in its formation. © 1979.