Frustrated Lewis pairs in ionic liquids – towards operando experiments

Frustrated Lewis pairs (FLPs) are a combination of a Lewis acid and a Lewis base (e.g. borane/phosphine), prevented from forming an adduct by steric hindrance. In a solvent, the acid and the base remain partly associated in a weakly bound encounter complex, in which the HOMO orbital of the base and the LUMO orbital of an acid remain free. This allows for unique, transition metal-like reactivity of FLPs, including metal-free activation of H2. Our past work served as the first direct experimental evidence for the existence of encounter complex in benzene, and more recently – for enhanced encounter complex formation in ionic liquids (ILs). Here, we propose the study of FLP-IL solutions that are supported on a porous solid (MCM-41), to explore differences between bulk solutions and solutions in pores, and building towards the study of metal free, in operando hydrogenations.