Chemical Triggers for Spin-State Switching: Discovery and Control of Switching Mechanisms

Colorado State University, Fort Collins CO

Investigators

Abstract

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Matthew Shores of the Department of Chemistry at Colorado State University (CSU) is exploring new classes of transition metal complexes that can serve as molecular switches. The goal of the research is to understand how host-guest interactions alter the structure of coordination complexes and change their magnetic properties. These results will inform design principles for the development of chemical sensors, switchable molecular magnets, and magnetic resonance contrast agents. The project combines several synthetic, measurement and computational techniques to provide diverse training for the research students involved. Interactions with the CSU Chemistry Research Experiences for Undergraduates program and collaborations with researchers at CSU-Pueblo aim to broaden participation from underrepresented groups. The group's expertise in magnetic measurements and data interpretation will promote discovery via several ongoing and new magnetic collaborations with inorganic and materials chemistry research groups around the country. Complexes that can exist in and reliably switch between two well-defined magnetic states offer the possibility for functional materials development at the nano- and molecular length scales. The proposed research aims to enhance magnetic property switching in transition metal complexes by controlling local geometry and ligand field effects via outer sphere, non-covalent interactions with guest molecules. Specific research goals for this project are: (1) computational understanding of thermodynamics and distortion pathways in magnetic-state switching, toward predictive models; (2) exploration of new chemical triggers and new ions for guest-dependent spin-state switching complexes; and (3) external control of axial magnetic anisotropy in Co(II) single-molecule magnet complexes. The ultimate aim is to gain new understanding in the design of novel mechanisms for magnetic property switching, and contribute new sensing architectures relevant to chemical sensing and molecular imaging applications. 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.