The Spectroscopic, Electrochemical and Structural Characterization of a Family of Ru Complexes Containing the C2-Symmetric Didentate Chiral 1,3-Oxazoline Ligand and Their Catalytic Activity

The structural, spectroscopic, and electrochemical characterization and a preliminary catalytic investigation of a family of Ru^II complexes with general formula [Ru(Y)(terpy)(phbox-R)]ⁿ⁺ [where terpy is 2,2:6,2-terpyridine, phbox-R is a C₂-symmetric bidentate oxazoline ligand (R = Et or iPr), and Y is a monodentate ligand], are discussed. The X-ray structure of [RuCl(terpy)(phbox-iPr)]²⁺ has been solved and confirms, as we described recently, the predicted generation of the less hindered atropisomer, which is determined by the conformation of the stereogenic centers in the bidentate ligand. The catalytic properties of the aquo complexes have been tested in epoxidation reactions, and moderate selectivity for the epoxides is obtained for styrene and trans-stilbene when using PhI(OAc)₂ as co-oxidant.