NSF Award
1903593
Scientists can impart desirable properties, such as flexibility or the ability to conduct electricity, into materials through strategic design of the chemical components that make up the materials. One of the most important considerations in this endeavor is how the chemical components within a material interact with each other. The Bowling and Speetzen research groups at the University of Wisconsin-Stevens Point (UWSP) collaborate with the Bosch group at the Missouri State University to study new organic compounds designed that increase understanding of important chemical interactions in materials. Their research also explores new strategies for achieving desirable properties. Calculations from the Speetzen research group not only help with interpretation of experimental results but also inform the design of new chemical structures. The strategies developed in these studies provide a foundation for creating materials that have enhanced electron transport capabilities, potentially leading to improved next-generation devices, such as thin-film transistors or light-emitting diodes. The undergraduate students responsible for this research gain expertise synthesizing, purifying, and characterizing novel chemical structures. They also gain insight into how fundamental chemical forces can be used to develop commercially useful materials. This combination of hands-on skills and chemical perspective prepares them well for careers in chemical industry or further studies in graduate school. <br/><br/>The molecules targeted in this collaborative study are classified as arylene ethynylenes (AEs) as they have alternating alkynes and aromatic rings throughout. AEs are attractive not only for their conjugation and rigidity, but also because the relatively free rotation around the single bonds linking alkynes and aromatic rings provides access to an array of unique intramolecular attractions or supramolecular structures. Molecules designed in the Bowling group laboratories utilize the tendency of rigid AE structures to stack in predictable arrangements in order to study charge transfer (CT) between electron-rich and electron-poor aromatic rings. Similar CT behavior is studied by installing electron-rich and electron-poor units within a single AE compound. Rotation of the AE backbone offers access to both CT-favorable and CT-unfavorable conformations, which provides insight into using CT as an organizational driving force and an opportunity for development of molecular switches. This project also seeks to realize the potential for AEs to function in supramolecular structures through the transition metal coordination of a hexagonal AE ligand and by using pnictogen bonding to assemble supramolecular pyramids or bipyramids that have the potential to serve as cages for specific guest molecules.<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.
