SYNTHETIC REPLICATORS AND EXTRABIOTIC CHEMISTRY

Synthetic replicators can be generated by covalent attachment of two complementary structures to form a self-complementary molecule. The complementarity refers to sizes, shapes, and the weak, intermolecular forces that characterize molecular recognition phenomena. New self-complementary structures were obtained by coupling imides to synthetic receptors for imides, and their properties as replicators were explored. The new structures use hydrogen bonding of thymine derivatives to diaminotriazines as the recognition vehicle, and autocatalytic behavior is experimentally demonstrated during the covalent coupling step. Self-complementarity and molecular aggregation are discussed in terms of orientation of recognition surfaces with respect to one another. The development of other replicating systems based on alternative binding forces is discussed. The term extrabiotic is proposed for synthetic systems which exhibit lifelike behavior.