Cooperative Interactions in a Ternary Mixture

An essential aspect of any recognition event is cooperative interaction. 1H NMR titrations have been used to detect the presence of cooperative interactions in a hydrogen-bonded termolecular complex (right). The three molecular components have little conformational freedom, and so the observed cooperativity is attributed to enthalpic effects. The hydrogen-bonding interactions polarise the amide groups and enhance the magnitudes of the individual hydrogen bonds in the ternary complex compared with those in the analogous bimolecular complexes.