Anomalous dispersion refinement as a tool to resolve oxidation states in cobalt complexes

Cobalt complexes are promising alternatives to precious metal catalysts in energy conversion and small-molecule activation. A key challenge is to determine their formal oxidation states in crystalline materials, as these states control reactivity and catalytic behaviour. Conventional crystallography is generally insensitive to the small variations in electron density that distinguish oxidation states, while X-ray absorption spectroscopy (XAS) provides only averaged information across the sample. In this project, six cobalt complexes representing different oxidation states will be studied at the synchrotron by combining single-crystal diffraction and XAS. Direct comparison of structural and spectroscopic data will test a new crystallographic approach for extracting oxidation state information from diffraction measurements, providing new insight into cobalt chemistry and advancing crystallographic methodology.