M−C bond homolysis in coinage‐metal [M(CF3)4]− derivatives

Abstract

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. 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 energy‐resolved 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.