Synthesis and crystal structure of Ru 3(CO) 8(C 16H 22). The insertion of isopropenylacetylene into RuC bonds and the opening of a stable closed triruthenium cluster

Abstract

The title complex is obtained by reaction of the very stable HRu 3(CO) 9C 2Bu t hydride with excess of isopropenylacetylene in hydrocarbon solvents. It has been characterized by elemental analysis and i.r. spectra, although in the mass spectrometer decomposition occurs. The crystal structure has been determined by X-ray methods. Crystals are triclinic, space group P 1 with Z = 2 in a unit cell of dimensions a = 11.331(9), b = 14.173(11), c = 9.022(8) Å, α = 80.79(7), β = 104.47(8), γ = 105.48(8)°. 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 5192 observed reflections. The complex consists of an open, bent tri-metal atom arrangement, coordinated by eight terminal carbonyls and, through σ, and η-bonds, by an organic moiety deriving from the condensation of two isopropenylacetylene molecules with one of t-butyl-acetylene. Hydrogen shift and transfer occurs in the reaction and two isopropenylacetylenic molecules interact in a different way with the C(σ-π) of the C 2Bu t group of the parent hydride. The resulting substituted seven carbon chain interacts with the three metals in a different way. This cluster opening is noteworthy as, until now, only CO substitution was obtained in the reactions of HRu 3(CO) 9C 2Bu t.