New Anion Binders Based on Aromatic Linear and Cyclic Aromatic Oligoamides

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Bing Gong of the State University of New York at Buffalo will be studying designer molecules with cyclic scaffolds known as macrocycles and how they interact with anions. This research aims to further understanding of how macrocycle design can be finely tuned to build in anion specificity and to establish new ways to bind particular anions, especially for those that are important for energy and the environment. The team will also be looking at how these macrocycles can move anions through different barriers such as cell membranes or non-polar organic solutions, which could be useful in many different fields. This project will integrate molecular design with experimental studies and provide research training opportunities for undergraduate and graduate students, including students from underrepresented groups. The research results will be publicized broadly in the scientific community and incorporated into undergraduate and graduate teaching. The macrocycles being targeted herein have a constrained aromatic oligoamide backbone that enforces the convergent placement of multiple amide NH and phenyl CH groups. These NH and CH groups define an electropositive binding cavity that is highly pre-organized for binding anions. Because of their hydrogen-bonding capabilities and differences in preference for anions, the macrocycles are expected to exhibit versatile binding capabilities for anions with varying properties. The macrocycles will assist in transporting anions across cell membranes or bulk non-polar organic solvents. The efficiency and selectivity of anion transport will be assessed using established fluorescence assays including those based on vesicles (liposomes) or those using U-shaped tubes. This research team will (1) optimize and scale up the synthesis of the anion-binding macrocycles, (2) conduct systematic anion binding studies to quantify the binding affinities of the macrocycles with different anions in various solvents, and (3) examine anion transport across lipid bilayers or non-polar organic solvents to determine the efficiencies and selectivity of transporting homologous series anions, such as halides and oxoanions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.