Footprint Catalysis. IV. Structural Effects of Templates on Catalytic Behavior of Imprinted Footprint Cavities

Abstract

Abstract Footprint catalysts are silica(alumina)gel catalysts with tailored specificities. Their catalytic sites are “molecular footprint-like” cavities formed by a molecular imprinting procedure with templates, which are referred to as transition-state or reactive-intermediate analogs of the catalyzed reactions. To clarify the relationship between the structural feature of template molecules and catalytic behavior, seven footprint catalysts were prepared by imprinting with templates of several types closely related to the substrates, benzoic anhydride and acetic anhydride; their catalytic activity and thermodynamic parameters for 2,4-dinitrophenolysis were then estimated. Among these catalysts, a catalyst imprinted with N,N′-dibenzoylbenzenephosphonediamide, a tetrahedral intermediate analog for benzoic anhydride substrate, showed a 10-fold higher catalytic activity than did the other imprinted catalysts.