Surface Chemistry Underpinning Enantioselective Heterogeneous Catalysis: Supramolecular Self-Assembly of Chiral Modifiers and Pro-Chiral Reagents on Ni{111}

Abstract

One of the most heavily studied examples of enantioselective heterogeneous catalysis is the hydrogenation of β-ketoesters over chirally modified Ni catalysts. We use scanning tunneling microscopy to investigate the interaction of the simplest β-ketoester, methylacetoacetate, with Ni{111} surfaces premodified with (S)-glutamic acid. The behavior of methylacetoacetate is strongly dependent on the initial modifier coverage. At an intermediate (S)-glutamic acid coverage, two distinct domains are identified which correspond to ordered arrangements of glutamate and methylacetoacetate in different stoichiometric ratios. The implications of our findings for enantioselective catalysis are discussed.