M-C Bond Homolysis in Coinage- Metal [ M( CF3) 4] @ Derivatives

A comparative study of the homoleptic [ M( CF3) 4] @ complexes of all three coinage metals ( M= Cu, Ag, Au) reveals that homolytic M @ C bond cleavage is favoured in every case upon excitation in the gas phase ( CID-MS2). Homolysis also occurs in solution by photochemical excitation. Transfer of the photogenerated CF3 C radicals to both aryl and alkyl carbon atoms was also confirmed. The observed behaviour was rationalized by considering the electronic structure of the involved species, which all show ligand-field inversion. Moreover, the homolytic pathway constitutes experimental evidence for the marked covalent character of the M @ C bond. The relative stability of these M @ C bonds was evaluated by energyresolved mass spectrometry ( ERMS) and follows the order Cu< Ag! Au. The qualitatively similar and rather uniform behaviour experimentally observed for all three coinage metals gives no ground to suggest variation in the metal oxidation state along the group.