Formation of [FeM(η-C5H5)(CO)4(µ-CO)(µ-CRCR′H)](M = Fe or Ru) complexes from the reaction of [MH(η-C5H5)(CO)2] with [Fe2(CO)9] and acetylenes. X-Ray structure of [FeRu(η-C5H5)(CO)4(µ-CO)(µ-CPhCPhH)]

Abstract

The complexes [MH(η-C₅H₅)(CO)₂](M = Fe or Ru) react with an equimolar [Fe₂(CO)₉]–acetylene mixture in tetrahydrofuran affording [FeM(η-C₅H₅)(CO)₄(µ-CO)(µ-CRCR′H)][M = Fe, R = R′= Ph, (1), or H, (2); R = Ph, R′= H (3); R = H, R′= Bu^t, (4); M = Ru, R = R′= Ph (5); R = SiMe₃, R′= H (6)]. The structure of (5) was established by single-crystal X-ray crystallography. It crystallizes in the space group P2₁/n with Z= 4 and a= 14.863(4), b= 14.542(4), c= 10.186(3)Å, and β= 97.09(3)°. The structure was solved by direct methods and refined by least squares to a final R of 0.067. It consists of Ru(C₅H₅)(CO) and Fe(CO)₃ fragments linked by CO and 1,2-diphenylethenyl bridges and a metal–metal bond. A possible mechanism for the formation of the complexes is proposed on the basis of the activation of the acetylenes by [Fe₂(CO)₉] and subsequent insertion into the M–H (M = Fe or Ru) bond.