NSF Award
2403941
With support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professor Amar Flood of Indiana University will engage in studies directed at understanding the rules of ion-driven self-assembly. This project centers on negatively charged molecules, anions, and their capture inside the pores of donut-shaped macrocycles, called cyanostars. This work will investigate how to recognize specific anions and to change the reactivity of the anions, as well as the design of complementary cations to control how both positive and negative ions assemble into larger and more functional molecular architectures. The significance of anion-directed assembly is inspired by Nature’s use of bottom-up self-assembly and has the potential to impact the future of nanomanufacturing. The planned activity will benefit society by training graduate, undergraduate and postdoctoral coworkers in research, communication, and collaboration both nationally and internationally. Inclusive practices will be developed that foster a culture embracing diversity and equity in science. Activities are designed to broaden understanding of anion-based chemistry and supramolecular chemistry for undergraduate students with laboratory experiments. Outputs from the research have the potential to benefit researchers in other areas of chemistry, as well as industrial chemists looking to manipulate anions.<br/><br/>In this project on anion recognition, reactivity and assembly, the Flood research group will synthesize a series of organic anions and organic cations to understand how their binding dictates reactivity and hierarchical assembly with cyanostar macrocycles. The project has three Aims that use molecular synthesis and self-assembly, titration data and crystal structures as general methods to address the project goals. Aim 1 seeks to examine how additional positive and negative charges will change the binding of boron-based anions to cyanostars, and how the binding of borohydride reductants will alter their reactivity. Aim 2 aims to establish how the structures of organic cations can be used to control formation of salt bridges in the hierarchical assembly of ionic supramolecular architectures, and to confer stability, chirality, and dynamic behaviors. Aim 3 seeks to expand the role of organic ammonium cations in anion-driven assembly towards 1D polymers, 2D networks, and non-equilibrium systems under the control of light and chemical fuel.<br/><br/>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.
