Bond dissociation energies of carbonyl gold complexes: a new descriptor of ligand effects in gold() complexes?

Ligand electronic effects in gold( i ) chemistry have been evaluated by means of the experimental determination of M-CO bond dissociation energies for 16 [L-Au-CO] + complexes, bearing L ligands widely used in gold catalysis. Energy-resolved analyses have been made using tandem mass spectrometry with collision-induced dissociation. Coupled with DFT calculations, this approach enables the quantification of ligand effects based on the LAu-CO bond strength. A further energy decomposition analysis gives access to detailed insights into this bond's characteristics. Whereas small differences are observed between phosphine- and phosphite-containing gold complexes, carbene ligands are shown to stabilize the gold-carbonyl bond much more efficiently. A new experimental method using mass spectrometry was developed to evaluate ligand electronic effects on gold( i ) complexes.