Gold in Chalcogenide Square Planar Complexes is Electron Richer than is Commonly Considered: Other Cases of Inverted Ligand Field

Electron distribution and bonding in extended structures based on square planar gold complexes, traditionally classified as gold (III), have been addressed through solid-state DFT calculations. The band structure analysis, taken as a diagnostic tool, highlighted that, when the metal is associated with chalcogen atoms, the gold centers are more electron rich than the classic accepted description. This is in agreement with the Inverted Ligand Field (ILF) theory that predicts a metal center d10 configuration with two electrons vacancy on the orbital combinations of the ligands for sulfur, selenium and tellurium cases. A covalent bond is featured in oxygen compounds, a borderline situation between the ILF and the classical Ligand Field description. In conclusion, the gold atom in chalcogenide square planar complexes should be considered electron richer than commonly thought applying the traditional rules for calculating the oxidation state.