Computational studies on the mechanisms of hydrogen activation and catalytic hydrogenation by cooperative lewis pairs

Abstract

Hydrogenation is one of the most fundamental transformations in chemistry, and its applications range from the chemical industry to laboratory scale organic synthesis [1]. The formal de nition of hydrogenation includes the addition of hydrogens across an unsaturated chemical bond, usually in the presence of a catalyst. There are two strategies to e ect hydrogenation; direct hydrogenation (DH) and transfer hydrogenation (TH). The latter requires a non-H2 hydrogen source, often organic molecules, acting as the hydrogen donors. Some of the popular academic examples of TH include Birch reduction of arenes with sodium in ammonia [2], Meerwein-Ponndorf- Verley (MPV) reduction with sacri cial alcohols as hydrogen donors [3], hydride transfer from Hantszch ester [4], etc. Nevertheless, with respect to the reducing agents, all these reactions are stoichiometric and hence leads to the formation of an equivalent amount of waste. This renders such hydrogenations relatively ine ective for industrial applications. DHs, which utilize H2 gas as the source of hydrogen, are comparatively more economical and atom-e cient. Since all investigated catalytic reactions in this thesis belong to DH, we will restrict our discussion to this particular class of hydrogenation.