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, their physical and electronic structures, and their resultant magnetic properties. To find these relationships, we (1) prepare novel materials/molecules, which we do using Schlenk lines or inert atmosphere 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 the noninvasive study of physiology and disease, developing new quantum units for applications in quantum sensing and information processing, or finding new ways that spin-based effects manifest in chemical reactions. Below are some brief summaries of the areas of work in our lab, but check out our publications for more detailed information about these projects.
Magnetic Noise at the Molecular Level
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. One key factor that governs relaxation is magnetic noise - think movement of magnetic protons in water, or vibrations of proton-bearing organic groups - but exactly what signals are "embedded” in that noise is still a mystery. Understanding that noise will give us new insights into what spins can sense, and that insight, in the long run, will enable new types of magnetic resonance sensors for chemistry or other ‘noisy’ phenomena. We are working to understand how magnetic noise relates to molecular structure. Inorganic chemistry is rich in its insights of 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, specifically related to magnetic noise.
Metal-Nuclei-Based Molecular Imaging
Magnetic resonance Imaging (MRI) is one of the most powerful noninvasive techniques for studying physiology and disease. Though it creates precisely detailed anatomical images, developing molecular probes to overlay chemical information is still a formidable challenge. We are studying the sensitivity of magnetic nuclei based on metal ions (think 59Co and 51V) toward environmental physical and chemical effects, like temperature, acidity, and redox status. In this project, we create metal complexes with these nuclei in them and study them via exotic nuclear magnetic resonance experiments. Excitingly, this line work enabled us to discover 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.