Broad Overview
Electronic and nuclear magnetic moments (spins) are present in nearly all matter. Our group searches for relationships between the chemical structure/composition of molecules/materials and their physical and electronic structures. To find these relationships, we (1) prepare novel materials/molecules, which we do using Schlenk lines or one of our two glove boxes, and (2) thoroughly characterize prepared substances, applying an extensive array of spectroscopic and physical techniques. Our long term goal is to leverage this fundamental science to find radically new solutions to pressing technological challenges, such as noninvasive study of physiology and disease, as well as new quantum units for applications in quantum sensing and information processing. Below are some brief summaries of the areas of work in our lab, and be sure to check out our publications for more detailed information about these projects.
The Molecular Edge of the Spin Bath
Magnetic relaxation is the process by which magnetic moments flip under applied magnetic fields. This fundamental property is critical to use in a variety of applications, and understanding what features govern the rates of relaxation is a critical challenge in controlling metal-ion magnetism. We are working to understand how magnetic species that immediately neighbor a metal ion (the “edge” of the spin bath) influence the ion’s magnetic relaxation properties. Inorganic chemistry has many rules for how functional groups, solvent cages, etc, modify reactivity. We are pushing this knowledge in a new direction by focusing on the magnetic consequences of these chemical features.
Spin-Based Thermometry
Current magnetic resonance imaging (MRI) technology only images tissue. However, measuring local temperature within the body noninvasively would be a powerful diagnostic tool for cancer treatments and a deeper understanding of physiological temperature management that remains current invisible. We are studying how to use magnetic metal nuclei (e.g. 59Co and 51V) and nuclear-spin-based thermometers. In this project, we create metal complexes with these nuclei in them to discover new molecular design strategies for thermal sensitivity. In this work, we discovered the highest temperature sensitivity across all published nuclear magnetic resonance studies to date with a trinuclear cobalt complex that exhibits a 150 ppm shift per degree Celsius.
Metal-Complex EPR Imaging Probes
Electron paramagnetic resonance imaging (EPRI), the electron version of conventional proton 1H MRI, is a cutting edge biomedical imaging technique that can give detailed information on local chemical environment. This information, in many cases, is unattainable via conventional MRI. Yet, in the magnetic field of a modern MRI scanner, EPR spectroscopy requires high-power, high-frequency microwaves that can harm living tissue. We are developing metal-based molecular imaging probes that operate using low-frequency microwaves that are safe. In doing so, we explore how features of molecular geometry, ligand identity, and electronic structure impact low-frequency EPR spectral properties for metal complexes. Moreover, the work is mapping out a blind spot in magnetic resonance, which is focused on ever-higher fields and ever-higher frequencies.