A Bidentate NHC−Alkenyl Ruthenium(II) Complex via Vinyl C−H Bond Activation

A bidentate NHC−alkenyl ruthenium(II) complex has been obtained on deprotonation of imidazolium salts with a N−CH2CH2X branch (X = OMe, Cl) followed by reaction with [RuCl2(p-cymene)]2. Low-temperature NMR studies and intermediate trapping with BH3 indicate the formation of a CH2CH−NHC carbene followed by the intramolecular activation of a vinyl sp2 C−H bond on coordination to a ruthenium(II) center.