Conversion of a UO₂²⁺ Precursor to UH⁺ and U⁺ Using Tandem Mass Spectrometry to Remove Both "yl" Oxo Ligands

Multiple-stage collision-induced dissociation (CID) of a uranyl propiolate cation, [UO₂(O₂C-C≡CH)]⁺, can be used to prepare the U-methylidyne species [O═U≡CH]⁺ [J. Am. Soc. Mass Spectrom. 2019, 30, 796-805]. Here, we report that CID of [O═U≡CH]⁺ causes elimination of CO to create [UH]⁺, followed by a loss of H^• to generate U⁺. A feasible, multiple-step pathway for the generation of [UH]⁺ was identified using DFT calculations. These results provide the first demonstration that multiple-stage CID can be used to prepare both U⁺ and UH⁺ directly from a UO₂²⁺ precursor for the subsequent investigation of ion-molecule reactivity.