Preparation of [Ru(η6-C6Me6)Cl(CCPh)(RNC)](R = C8H9 or C6H2Me3-2,4,6) and its reaction with tetracyanoethylene. Crystal structures of [Ru(η6-C6Me6)Cl{C[C(CN)2]CPhC(CN)2}(C8H9NC)] and cis-[RuCl2(C8H9NC)2]

Abstract

Reaction of [Ru(η⁶-C₆Me₆)Cl₂(RNC)] with phenylacetylene in the presence of potassium hydroxide in methanol gave the corresponding acetylide complex [Ru(η⁶-C₆Me₆)Cl(CCPh)(RNC)](R = C₈H₉1a or 2,4,6-Me₃C₆H₂1b). Compound 1a reacted with triphenylphosphine at reflux in toluene to give [Ru(η⁶-C₆Me₆)Cl(CCPh)(PPh₃)]2 and [RuCl(CCPh)(C₈H₉NC)(PPh₃)]3. When 1a was treated with tetracyanoethylene (tcne) at room temperature [Ru(η⁶-C₆Me₆)Cl{C[C(CN)₂]CPhC(CN)₂}(C₈H₉NC)]4 was obtained. The structure was confirmed by an X-ray analysis: space group Pbca, a= 20.128(4), b= 17.821(6), c= 17.407(9)Å, and Z= 8. The molecule contains a ligand resulting from α,β addition of C(CN)₂ fragments to the acetylide group. Reaction of 2 with tcne gave [Ru(η⁶-C₆Me₆)Cl{C(CN)₂CPhCC(CN)₂}]5 which has lost the terminal isocyanide in 4. Preparation and X-ray analysis of square-planar cis-[RuCl₂(C₈H₉NC)₂] were also carried out: space group P, a= 10.573(3), b= 10.865(3), c= 8.244(2)Å, α= 99.66(2), β= 93.37(2), γ= 85.85(3)° and Z= 2. The structure consists of a pair of molcules of cis configuration with a centrosymmetry, but there is no interaction between the ruthenium atoms.