Gas-Phase Actinide Ion Chemistry: FT-ICR/MS Study of the Reactions of Thorium and Uranium Metal and Oxide Ions with Arenes

Gas-phase reactions of M +, M 2+, MO + (M = Th and U), and UO 2 + with several arenes (benzene, naphthalene, toluene, mesitylene, hexamethylbenzene, and 1,3,5-tri- tert -butylbenzene) have been studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). For M + ions C−H and/or C−C bond activation was observed in the primary reactions for all of the arenes studied. MO + and UO 2 + ions yielded the adduct species, with the exceptions of the reactions of MO + with hexamethylbenzene and 1,3,5-tri- tert -butylbenzene, for which bond activation products also formed. In the M 2+ reactions charge-transfer products dominated, but formation of doubly charged bond activation products was also observed with all the arenes. Product distributions and reaction rate constants are reported and related to the electronic configurations of the reacting ions, the polarizabilities of the arenes, and the energetics of the different reactions.