Dynamic Covalent Self-assembly and Self-sorting of 2D and 3D Nanohoops and Cages

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Johnson of the University of Oregon will expand on a molecular self-assembly strategy to make stable, complex molecular cages and large cyclic structures from simple building blocks. This project aims to establish design rules on how the shapes and sizes of the building blocks as well as subtle effects in the self-assembly process will influence the structures and properties of the resulting products. This research may provide efficient routes to new dynamic structures for stimuli-responsive materials. Professional development activities for students will include experience in mentorship and participation in Lens of the Market workshops to learn the basics of intellectual property protection and research translation. The Johnson lab has developed a design strategy to use Group 15 ions (or Cu+) as directing elements in self-assembly reactions of oligothiols to direct formation of discrete disulfide assemblies under mild oxidizing conditions. These products are formed under thermodynamic control to yield a variety of macrocycles, dimeric cages, unsymmetrical cages, and tetrahedral assemblies. The project will involve three specific aims: Aim 1 will explore the fundamental physical organic chemistry of dynamic disulfide formation in order to develop subtle control of thiol oxidation and self-assembly pathways; Aim 2 will seek to harness subtle effects in ligand sterics, shape, and reactivity to control self-assembly and influence product distribution. Aim 3 will extend the approach to controlling disulfide assembly in water. 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.