An unexpected formation of a Ru(III) benzylidene complex during activation of a LatMet-type ring-opening polymerisation catalyst

Upon activation with C2Cl6 known latent Ru metathesis catalyst LatMet (13) exhibited activity in RCM and in ROMP of DCPD. A by-product of such activation, an aryloxybenzylidene ruthenium(III) complex 17 have been independently synthesised by reacting 13 with C2Cl6. This unique complex was characterised by spectroscopic and electrochemical methods, and by X-ray crystallography. To the best to our knowledge, this is the first isolated and structurally determined Ru(III) alkylidene complex reported.