Ruthenium(II) DMSO complexes with CC cyclometalated phenylimidazol NHC ligands

We present the synthesis of cyclometalated ruthenium N-heterocyclic carbene (NHC) complexes of the general formula [Ru(C<^>C*)(DMSO)(3)Cl] and their use as starting material for the synthesis of a heteroleptic 2,2'-bipyridine (bpy) complex [Ru(bpy)(C<^>C*)(DMSO)Cl]. Starting from the corresponding eta(6)-(p-cymene) complexes [Ru(p-cymene)(C<^>C*)Cl], the pi-coordinated aryl ligand is substituted by three S-bound dimethyl sulfoxide ligands. In the course of this substitution, the complexes undergo a change in geometry from facial to meridional, which is unambiguously proven by solid state structure determination and DFT calculations. The labile DMSO ligands can be substituted by bidentate ligands as shown for the widely used 2,2'-bipyridine. The resulting air- and moisture-stable heteroleptic complex features two bidentate (C<^>C* + bpy) and two monodentate (Cl- + DMSO) ligands. (C) 2016 Elsevier B.V. All rights reserved.