The bis(trifluoroacetate) analogue of the first-generation Grubbs catalyst: Synthesis, X-ray structure, and metathesis activity of [Ru(CF3CO2)(η2-CF3CO2)(CHPh)(PCy3)2]

A simple synthesis of [Ru(CF3CO2)(η2-CF3CO2)(CHPh)(PCy3)2] from dimeric [Ru2(CF3CO2)2(μ-CF3CO2)2(CHPh)2(PCy3)2(μ-H2O)] is described. The new complex crystallizes in monoclinic system (P2(1)/c space group) with distorted octahedral coordination. The very low metathesis activity of this new ruthenium benzylidene complex demonstrates that substitution of chlorides with trifluoroacetates in [RuCl2(CHPh)(PCy3)2] results in loss of the catalytic activity.

The bis(trifluoroacatete) counterpart of the first-generation Grubbs catalyst, i.e. [Ru(CF3CO2)2(CHPh)(PCy3)2], was synthesized in high yield by addition of PCy3 to [Ru2(CF3CO2)2(μ-CF3CO2)2(CHPh)2(PCy3)2(μ-H2O)]. The new complex is octahedral, with one monodentate and one bidentate carboxylic ligand. The very low metathesis activity of this complex clearly demonstrates that replacement of chlorides with trifluoroacetates in Grubbs catalyst results in a drastic decrease of the catalytic activity.Figure optionsDownload as PowerPoint slide