Acid–Base Bifunctional Catalytic Surfaces for Nucleophilic Addition Reactions

This article illustrates the modification of oxide surfaces with organic amine functional groups to create acid-base bifunctional catalysts, summarizing our previous reports and also presenting new data. Immobilization of organic amines as bases on inorganic solid-acid surfaces afforded highly active acid-base bifunctional catalysts, which enabled various organic transformations including C--C coupling reactions, though these reactions did not proceed with either the homogeneous amine precursors or the acidic supports alone. Spectroscopic characterization, such as by solid-state MAS NMR and FTIR, revealed not only the interactions between acidic and basic sites but also bifunctional catalytic reaction mechanisms.