Ruthenium complexes containing butatrienylidene and related ligands: synthesis, characterisation and chemistry

Abstract

The reaction of buta-1,3-diyne with [Ru(thf)(PPh₃)₂(η-C₅H₅)]⁺ (thf = tetrahydrofuran) to give [Ru(CCCCH₂)(PPh₃)₂(η-C₅H₅)]⁺ has been studied. This complex adds nucleophiles at C_γ, as expected from theory and consideration of the protection afforded to C_α by the bulky PPh₃ ligands. The products were alkenylethynyl complexes (from aprotic nucleophiles) or methylallenylidene complexes (from protic nucleophiles, with H migration to C_δ). With water, the complex [Ru{CCC(O)Me}(PPh₃)₂(η-C₅H₅)] is formed. The single-crystal structures of [Ru{CCCMe(X)}(PPh₃)₂(η-C₅H₅)][PF₆] (X = NPh₂ or C₄H₃NMe-2) and [Ru(CCCHCHCl-trans)(PPh₃)₂(η-C₅H₅)] have been determined.