Cyclopentadienyl-ruthenium and-Osmium Chemistry. IX. Some Substituted η¹-Vinylidene and η¹-Acetylide Complexes

Abstract

Reactions between RUCI(PPh₃)₂(η-C₅H₅), RuCI(L₂)(η-C₅H₅)(L₂ = dppm or dppe) or OsBr(PPh3)₂-(η-C₅H₅) and the alk-1-ynes HC₂R (R = Me, Pr, CO₂Me, Ph, C₆H₄F-p or C₆F₅), in the presence of NH₄PF₆, NH₄BF₄ or NaBPh₄, have given the corresponding cationic η¹-vinylidene complexes [Ru(C=CHR)(PPh₃)₂(η-C₅H₅)]⁺,[Ru(C=CHPh)(L₂)(η-C₅H₅)]⁺ or [Os(C=CHP~)(PPh₃)₂(η-C₅H₅)]⁺. These cations are readily deprotonated to give the corresponding η¹-ethynyl derivatives Ru(C₂R)-(PPh₃)₂(η-C₅H₅), Ru(C₂Ph)(L₂)(η-C₅H₅) or OS(C₂P_h)(PPh₃)2(η-C₅H₅). Addition of HPF₆ or [R'₃O]PF₆ (R' = Me or Et) to the latter affords the vinylidene complexes containing C=CHR and C=CRR' ligands (R = Me, Pr, CO₂Me, Ph, C₆H₄F-p or C₆F₅; R' = Me or Et), respectively. The vinylidene complexes are characterized by ν(CC) bands at c. 1650 cm^-1 and the metal-bonded carbon (¹³C) resonance at c. 360 ppm.