Autocatalytic Activation of a Ruthenium-PNN-Pincer Hydrogenation Catalyst.

In this article, we describe a detailed experimental and computational study of the activation mechanism for a highly active pincer ruthenium(0) precatalyst for the hydrogenation of polar organic compounds. The precatalyst activates by reaction with 2 equiv of hydrogen, resulting in a net oxidative addition to ruthenium and hydrogenation of an imine functional group on the supporting ligand. The kinetics of precatalyst hydrogenation were measured by UV-visible spectroscopy under catalytically relevant conditions (10-39 bar hydrogen, 298 K).