Negatively charged organic uranyl species (HOUO2OH), prepared with uranyl acetate using electrospray ionization multiple-stage tandem mass spectrometry, was reacted with oxygen to yield a novel UO5 anion species in the gas phase. The molecular structure of UO5 was confirmed by using collision-induced dissociation (CID) mass spectrometry experiments. The effects of experimental parameters on the yield of UO5 anion were experimentally evaluated. Upon gas phase collisions, UO5 anions released oxygen when a certain amount of energy was deposited on the UO5 anions. The data have shown that the electron cloud radius (r) of the polyatom anion (e.g. HOUO2OH) was tunable within the range rinert≤rreactive≤rdecomposition by changing the collision energy of CID. This mechanism can be further used to catalyze a certain type of chemical reactions.

Key words: ESI tandem mass spectrometry, UO5, reaction time, collision energy, gas-phase reaction, uranyl acetate