Advancements in X-Ray Spectroscopy of Biologically Relevant Transition Metal Catalysts using X-Ray Free Electron Lasers

First row transition metals are at the center of many biological catalysts due to their abundance in nature and ability to accept and donate electrons with relative ease. Determining the electronic and structural changes as a catalytic process proceeds is difficult due to challenges associated with in situ and operando studies. X-Ray spectroscopic methods are powerful tools to elucidate oxidation states, spin states, and nature of the chemical environment with element specificity. X-Ray free electron lasers (XFELs) have brilliant pulses with durations in the femtosecond and shorter time domain, which allows for mechanistic studies under functional conditions with minimal sample damage. Studies of heme proteins and the oxygen evolving complex of photosystem-II are used to elucidate the current capabilities and limitations of X-Ray spectroscopy using XFELs.