BIOMIMETIC CHEMISTRY

Several cases are described in which the chelate effect contributes to binding and catalysis. In the first examples, dimers made up of linked cyclodextrins show very strong selective substrate binding, and with catalytic groups in the linkers they are effective catalysts of reactions of bound substrates. In later examples, chelate binding of transition states by a base and an acid produce effective catalysts whose geometric preferences reflect the detailed mechanisms of the catalyzed processes. In the final examples, chelate binding to biological receptors of some molecules with two polar end groups produces a class of particularly effective cytodifferentiating agents, of potential use in cancer chemotherapy.