Ruthenium mediated C-H activation of 2-(arylazo)phenols: characterization of an intermediate and the final organoruthenium complex

Reaction of 2-(arylazo)phenols with Ru(PPh(3))(2)(CO)(2)Cl(2)] affords a family of organometallic complexes of ruthenium(II) of type Ru(PPh(3))(2)(CO)(CNO-R)], where the 2-(arylazo)phenolate ligand (CNO-R; R = OCH(3), CH(3), H, Cl, and NO(2)) is coordinated to the metal center as tridentate C,N,O-donor. Another group of intermediate complexes of type Ru(PPh(3))(2)(CO)(NO-R)(H)] has also been isolated, where the 2-(arylazo)phenolate ligand (NO-R) is coordinated to the metal center as bidentate N,O-donor. Structures of the Ru(PPh(3))(2)(CO)(NO-OCH(3))(H)] and Ru(PPh(3))(2)(CO)(CNO-OCH(3))] complexes have been determined by X-ray crystallography. All the complexes are diamagnetic and show characteristic (1)H NMR signals and intense MLCT transitions in the visible region. Both the Ru(PPh(3))(2)(CO)(NO-R)(H)] and Ru(PPh(3))(2)(CO)(CNO-R)] complexes show two oxidative responses on the positive side of SCE.