Synthesis, characterization and structure of the ethylene-bridged dimer [Cp(CO)2RuCH2CH2Ru(CO)2Cp] and comparison of its reactivity with that of [Cp(CO)2RuCH2CH3] and [Cp(CO)2Ru(CH2)5Ru(CO)2CP]: Models for Fischer-Tropsch surface intermediates

Article abstract of DOI:10.1016/0022-328X(95)05897-X

The diruthenium ethylene-bridged complex [Cp(CO)₂RuCH₂CH₂Ru(CO)₂Cp] (Cp = η⁵-C₅H₅) (1) has been prepared by two different synthetic routes. The complex has been fully characterized by IR, ¹H and ¹³C NMR spectroscopy, mass spectrometry and X-ray crystallography. The complex crystallizes in the triclinic space group P1 (Z = 1) with a = 6.060(1), b = 6.990(2) and c = 10.097(1) A and α = 85.30(1), β = 76.86(1) and γ = 74.46(2)°. The structure was refined to R(F) = 0.029 and shows that the CpRu(CO)₂ units are centrosymmetrically bonded to each end of the ethylene fragment in a trans arrangement. The use of 1 as a model for ethylene on a metal catalyst surface is explored and some reactivity studies of 1 are described. Some reactions of [Cp(CO)₂RuCH₂CH₃] (2) are also reported and compared with the reactions found for 1. A reaction sequence of the pentamethylene-bridged compound [Cp(CO)₂Ru(CH₂)₅Ru(CO)₂Cp] (3) is found to give a high yield of 1-pentene.