CAREER: Exocyclic Imine Ligands for Electron Transfer

This award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2). With support from the Chemical Synthesis program of the Division of Chemistry, Kensha Marie Clark of the Chemistry Department at the University of Memphis will engage in the synthesis of bimetallic and multi-metallic complexes bridged by redox-active, exocyclic imine ligands. In addition, the electronic and magnetic properties of these compounds will be studied. Electrons should readily flow through these species. Consequently, they will be deployed for construction of molecular wires and magnetically ordered materials, which have a range of applications in energy transfer, electronic devices, and logic gates for advanced computing. An educational plan targets the retention of University of Memphis chemistry and other science majors by providing support for undergraduate students during matriculation in the general chemistry sequence and during their transition into organic chemistry. These activities include a series of bootcamps that are designed to provide the students with a first research experience. This project aims to develop new electronic materials by exploiting the electronic properties imparted by bridging ligands that are derived from π-conjugated exocyclic α-diimines. The project capitalizes on redox non-innocence in transition metal complexes for the purpose of: (1) predicting electronic and magnetic behavior, (2) exploring ligand facilitated intermetallic interactions, and (3) designing of new functional molecules. The advantage of these systems stems from the energetic closeness of the frontier orbitals of conjugated α-diimines and d-orbitals of transition metals, a prerequisite for the incoherent hopping mechanism of electron transfer between the transition metal donor and the bridge. The ligands, which contain pyracene and pyrene moieties, have predictable electronic behavior that is to be utilized to enforce electron-hopping between metal centers and to control magnetic ordering in molecular complexes. Molecular wires engineered with built-in directionality and rationally designed magnetic molecules are being targeted for synthesis. 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.