Cyclometallated ruthenium(ii) complexes with ditopic thienyl NHC-ligands: syntheses and alkyne annulationst

A series of six RuX(2-th enyl-NHC)(p-cymene)] complexes (9a-c and 10-14; X = halido) have been prepared via NHC directed C-H activation. All complexes have been fully characterized, and the molecular structures of four complexes are reported. The rotational barrier of the N-benzyl substituent in the bromido complex 9b has been measured by variable temperature I-H NMR spectroscopy. Preliminary reactivity studies of complex 12 with alkynes provided four new annulated aza-heterocyclic th ophenes.