This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports Professor Mary Elizabeth Williams at the Pennsylvania State University to use metal coordination to self-assemble artificial peptide duplexes that operate as functional redox systems for studying multiple electron transfers. Structures with directly connected redox sites would allow multi-electron transfers between weakly coupled metal complexes predominantly by electron hopping, a regime that is largely unexplored in molecular assemblies. Functional architectures with di- and trimetallic model compounds will be built and studied as to how electrons move through them. Goals are to: 1) use metal coordination to self-assemble homometallic macromolecules; 2) extend this approach to make modular and heterofunctional structures; and, 3) measure electron transfers in di- and trimetallic functional redox systems. Initial work will be done with homometallic systems and move forward with simple heterofunctional structures. Facile modifications using available monomers and rational design (i.e. hairpin and self-aligning strands) will be used in constructing these assemblies. NMR and solution x-ray scattering will be applied to obtain structural analyses of the solution-phase homometallic and heterometallic species. Electrochemical methods and time resolved fluorescence spectroscopy will be used to test and understand the mechanisms and rates of electron transport in the multi-electron transfers of these self-assembled structures.
Student and postdoctoral researchers will be broadly trained in molecular design and synthesis, use of a wide range of experimental methodologies, and electron and energy transfer theory. The complexity of this project requires that researchers working on these problems make connections to groups and experts within the department and across campus, and with researchers at Argonne National Labs. Students will be recruited through the Research Experience for Undergraduates and the Penn State Summer Research Opportunities Programs. Senior graduate students and postdoctoral researchers will serve as mentors and oversee the projects of younger group members, thereby gaining teaching and supervisory experience as part of their professional training.
