Supramolecular Self-Assembly and Capture as a New Route to 3D Cyclophanes

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

Self-assembly -- a process analogous to a puzzle programmed to put itself together -- is a powerful tool for synthetic chemists to assemble large, complex organic molecules. This research program uses a self-assembly approach to develop highly efficient routes to complex, three-dimensional (3D) organic molecules known as "cyclophanes". These new chemical entities feature unusual properties in their interaction with light, the binding of "guest" molecules within their cage-like structures, and their ability to serve as precursors for polymeric materials (plastics). One broader impact of this research is the possible development of new building blocks for the parylene industrial polymerization process that provides polymer coatings for sensitive devices and electronics. Graduate student professional development activities continue to encourage the transfer of basic science discoveries to application. New professional development opportunities include implementing individual development plans, providing opportunities for internships, developing experience in mentorship, and supporting the Women in Graduate Sciences group at the University of Oregon. The involvement of undergraduate researchers in the program continues to be a priority as well. This project specifically seeks to advance a preliminary discovery showing that simple treatment of thiol ligands and a pnictogen source with iodine provides equilibrating thermodynamic mixtures of discrete disulfides that can be "kinetically trapped" via sulfur-extrusion chemistry to yield complex (thia)cyclophanes. This efficient two-step process of self-assembly and kinetic capture provides cyclophanes in scalable, high-yielding reactions. This research seeks to advance these methods and to convert the self-assembled thiacyclophanes, which are known precursors to hydrocarbon cyclophanes, into new cyclophane compounds through three primary aims. The researchers expand methods to synthesize new 2D and 3D self-assembled discrete disulfides using soft metal ions as directing elements. They also apply sulfur-extrusion chemistry to "kinetically trap" new thioether and hydrocarbon cyclophanes. Finally, the Johnson group scales-up the syntheses of new (hetero)cyclophanes and studies their initial properties. Cyclophanes are screened for their host-guest chemistry, optoelectronic properties, and use as monomers for new polymeric materials.