Synthetic Tuning of Ligand Field for Precise Control of Molecular Zero-Field Splitting

The field of quantum information science (QIS) is rapidly developing, and one major thrust is in the design of appropriate hardware to act as quantum bits, quantum sensors, quantum gates, and more. Molecules have been largely ignored in this discussion; yet, they hold much promise in their size and tunability. Understanding synthetic ways to control the spin and coherence properties would allow chemists to prepare designer molecules for use in either fundamental or applied QIS studies. In this proposal, we have selected titanium and vanadium as early transition metals to house molecular spin due to their relatively weak spin–orbit coupling (SOC) interactions. Such weak SOC confers greater flexibility in design of molecular systems, as it decreases the sensitivity of properties like g tensor and zero field splitting (ZFS) to the coordination environment. Our studies will target trigonal coordination complexes with electronic structures that mimic solid-state systems like nitrogen vacancy centers of diamond, and this will allow us to tune the ZFS and optical excited states. This will be accomplished by using ligand field theory to design molecular systems, by characterization of their magnetic and excited state properties, and by computationally defining principles and heuristics that control the structure–property relationships