The reactivity of HRu 3(CO) 9C 2Bu t. Synthesis and crystal structure of Ru 3(CO) 7{(C 2Bu t)[PhC 2(H)Ph](C 2Ph 2)}

Abstract

The title complex was obtained by treating HRu 3(CO) 9C 2Bu t with C 2Ph 2 or (η-C 5H 5) 2Ni 2(C 2Ph 2), and its structure was determined by X-ray methods. Crystals of the complex are monoclinic, space group P2 1/n with Z = 4 in a unit cell of dimensions: a = 17.230(11), b = 22.753(13), c = 9.229(8) Å, β = 93.57(7)°. The structure was solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least squares to R = 0.055 for 3041 observed reflections. The complex consists of an isosceles triangle of ruthenium atoms, bound to seven terminal carbonyls. One diphenylacetylene ligand, on one side of this triangle, forms two σ and one π bonds with the metal atoms. On the opposite side an organic ligand, formed by oligomerization of C 2Ph 2 and the C 2Bu t group from the starting compound with shift of the hydridic hydrogen on C 2Ph 2, interacts through σ and η bonds with all the metal atoms. Important features in the formation of the title complex are the attack of C 2Ph 2 to α-carbon atom of the acetylide in the starting complex and the hydridic hydrogen shift on the new organic chain. The role of the title complex in the reaction sequence of HRu 3(CO) 9C 2Bu t with alkynes is dicussed.