CAREER: Dynamic Hemilability Controlled by Cation-Responsive Pincer-crown Ether Catalysts

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

In this project funded by the Chemical Catalysis Program of the Chemistry Division, Professor Alexander Miller of the Department of Chemistry at the University of North Carolina at Chapel Hill is developing cation-responsive catalysts for the sustainable synthesis of chemical building blocks. Catalysts are vital in many industrial and laboratory chemical processes. Many catalysts involve a metal atom that contains a reactive center that can facilitate chemical reactions. However, this reactive center, itself, can be prone to reactions that can deactivate it. This project involves the development of ligands (groups that are attached to a metal) that contain one portion that is firmly bonded to the metal and another that can be relatively easily removed from the metal to open a reactive site. These ligands are called hemilabile ligands. The hemilabile ligands targeted contain a group that can bind to an external positive ion that remove that group from the metal. This permits a balance of activity and stability that advances catalysis relevant to the pharmaceutical and commodity chemical industries. The educational approach focuses on communication in chemistry. Graduate students are participating in a science communication initiative in collaboration with a local science center, the Morehead Planetarium, creating hands-on activities that illustrate the role of catalysis in everyday life. The Safety Net is also being established as an online network of safety resources to encourage communication between academic and industrial scientists. The research approach utilizes new "pincer-crown ether" ligands that contain a macrocylic cation receptor site to modulate reactivity. Mechanistic studies are establishing the parameters that allow cations to tune individual organometallic reactions steps, supporting the development of catalysts that exhibit distinct activity and selectivity in the presence of various cations. The combined education and research program is training graduate students in catalysis research, safe laboratory practices, and science communication with the public.