An 'Old Hydride' in a new synthesis: a convenient approach to Grubbs-type carbene complexes (PPh3)(2)Cl2Ru=CH-CH=CR2 and their hexacoordinate acetonitrile adducts

摘要

A convenient synthetic route to Grubbs-type complexes (PPh3)(2)Cl2Ru-CH-CH=CR2, by reacting Wilkinson's hydride (PPh3)(3)Ru(H)Cl with propargyl or allenyl chlorides, and the isolation of an adduct complex (CH3CN)(PPh3)(2)- Cl2Ru=CH-CH=CMe2 (3) by treatment of (PPh3)(3)Ru(H)Cl with 3-chloro-3-methyl-1-butyne in the presence of CH3CN are reported, NMR studies in CD2Cl2 show hexacoordinate (CH3CN)(PPh3)(2)Cl2Ru CH-CH=CMe2 (3) to be in equilibrium with CH3CN and pentacoordinate (PPh3)(2)Cl2Ru=CH-CH=CMe2 (2), the solid state structure of which is presented. X-ray characterization of [(CH3CN)(3)(PPh3)(2)Ru=CH-CH=CMe2](OTf)(2) (6), the first mononuclear, dicationic complex derived from a Grubbs-type carbene, obtained by treatment of (CH3CN)(PPh3)(2)Cl2Ru=CH-CH=CMe2 (3) with trimethylsilyl triflate in the presence of an excess of CH3CN has been performed. This result indicates the possibility of stabilizing such species by labile donor ligands. (C) 2002 Published by Elsevier Science B.V. [References: 46]