Metal Pincer Catalysts in Aqueous Media: Approaches With Water as Solvent, Reagent, and Molecular Hydrogen Storage

In this chapter, the role of water in metal pincer-catalyzed reactions is summarized. Briefly three categories can be described: (1) Water can act as polar and protic solvent for biphasic catalysis, with water-soluble pincer complexes in the catalyst phase. (2) The use of water in aqueous phase alcohol and aldehyde-reforming processes for low-temperature hydrogen generation. (3) The use of water in aqueous phase oxidation reactions where water acts as oxygen source, for example, for the oxidation of alcohols to carboxylic acids or the oxidation of amines to amides. Thus, water plays a role for potentially recyclable catalyst systems toward more sustainable organic synthesis or low-temperature energy storage and conversion systems.