Beyond Oxidation States: Distinguishing Chemical States of Gallium in Compounds with Multiple Gallium Centers.

The electronic structures of a series of gallium complexes are examined using X-ray absorption spectroscopy (XAS) in combination with ab initio calculations. The chemical states of Ga are strongly affected by the ligands and the bonding environment. For complexes containing multiple gallium sites, we demonstrate that XAS can identify the chemical state of each unique gallium center. A reliable understanding of the chemical nature of the core element in a coordination complex with strong core-ligand interaction can be obtained only when both experimental and theoretical approaches are combined.