EAPSI: Harnessing the Power of a Molecular Machine: A Bifunctional Supramolecular Switch Allowing for Multiple Catalytic Processes

Brewster James T, Austin TX

Investigators

Abstract

Nature utilizes highly efficient and specifically designed enzymes to facilitate the transformations necessary for life. The catalytic proficiency of these systems allows for complex modifications with specificity and efficiency not always accessible through synthetic methods. Thus, the design of supramolecular systems with the ability to mimic the key catalytic function of enzymes has been a chemist?s long-standing dream. This award supports development of a bifunctional, supramolecular switch allowing for multiple catalytic processes. This project is expected to result in a novel catalytic system allowing for the selective functionalization of substrates achieved through macrocyclic-based recognition with concomitant control of binding orientation. These studies will be conducted in collaboration with Professor Hegui Gong and Dr. Zhan Zhang of Shanghai University, both of whom are recognized as prominent researchers within the fields of organic synthetic methodology and supramolecular chemistry, respectively. In recent years increasingly diverse arrays of supramolecular catalysts have been developed. These systems utilize cooperative (geometric), steric, or electronic effects, as well as aggregation, host-guest, and other non-covalent interactions to bind and orient substrates for selective functionalization. Currently appealing in supramolecular catalysis is the use of so-called molecular switches, whose functionality can be altered by external stimuli. The goal of this research program is to prepare a bifunctional supramolecular switch with two separate catalytic functionalities that can be (de)activated by varying the applied stimuli (light or addition of a competing cation). Supramolecular catalysis shows promise of allowing for multiple switchable catalytic states, thus enabling precise control over sequences of transformations in an environmentally friendly manner (low catalyst loading, easily recoverable catalyst, minimal waste and energy requirements, and single-pot tandem reaction sequences). The pursuit of this project is thus expected to advance knowledge in supramolecular chemistry and molecular switches while providing a new approach to achieving catalysis. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.