Frustrated Lewis pairs (FLP) have distinct ability to activate small molecules, in particular hydrogen. Even though, heterolytic activation of hydrogen has been observed on a number of Lewis acid-base pair, the mechanism of hydrogen dissociation on FLP remains still unclear. It is believed that the driving force for the reaction is dependent on the cumulative acidity and basicity of the Lewis pair. Most of the reported FLP are generally based on B(C6F5)3 accompanied by tertiary amine, substituted pyridine (e.g. lutidine) or phosphine. The resulting adducts after hydrogen dissociation may be served as hydrogenation catalysts for imines, aziridines, borane-bound nitriles, silylenolethers, dimine and various N-based heterocycles. This discovery may provide new routes to catalytic reduction without using metals. Nevertheless, to the best of our knowledge, the concept of FLP has not been applied in metal-free heterogeneous catalysis as a set of Lewis acid/base pair bearing a suitable anchoring site has still to be experimentally established. Generally, heterogeneous catalysts offer easy separation of the catalyst from the product, catalysts recycling and working under continuously flow conditions in gas phase.In this communication we report the first supported FLP on oxide by surface organometallic chemistry. Preliminary studies have demonstrated successfully heterolytic cleavage of hydrogen to form supported zwitterionic ammonium/hydridoborate adducts. The resulting species have been characterized by solid state NMR (1H MAS, 11B MAS, 13C CP MAS, 19F MAS), FTIR and elemental analysis. Following this approach, supported FLP demonstrated activity in hydrogenation and the supported zwitterionic species were used as initiator for polymerization.

Preparation and characterization of the first supported Frustrated Lewis pairs: Application in hydrogenation and polymerization

248th National Meeting (2014)

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