In this project in the Organic Dynamics Program, Professor Francois N. Diederich will investigate "Cyclophanes to Study Principles of Molecular Recognition in Aqueous Solutions" in the Chemistry Department at the University of California, Los Angeles (UCLA). Molecular recognition is the study of designed polymolecular entities and assemblies formed between two or more chemical species and held together by intermolecular forces, the noncovalent bond. This fascinating and dynamic research area is recognized worldwide as an important intellectual and technological frontier in chemistry. These studies will lead to guidelines for the design of new hosts and to new insight into the workings of biological molecules. This information is especially valuable for those scientists interested in designing new receptors to selectively remove toxic molecules from waste waters or bodily fluids in humans. This study involves a comprehensive synthetic, physical organic, and computational approach to explain apolar complexation in aqueous solutions. The role of water will be defined in comparative investigations in aqueous and organic solutions. For these studies, a unique series of cyclophane receptors with apolar binding cavities is already available, and others will be prepared to reach specific objectives. Titration microcalorimetry is being used for accurate determination of the complete set of thermodynamic quantities for apolar complexation processes in aqueous and organic solutions. Hydrogen-deuterium isotope, salt, and buffer effects on apolar association are also being studied.