Collision‐induced dissociation of [UO 2 (NO 3 ) 3 ] − and [UO 2 (NO 3 ) 2 (O 2 )] − and reactions of product ions with H 2 O and O 2

Electrospray ionization (ESI) can produce a wide range of gas‐phase uranyl (UO 2 2+ ) complexes for tandem mass spectrometry studies of intrinsic structure and reactivity. We describe here the formation and collision‐induced dissociation (CID) of [UO 2 (NO 3 ) 3 ] − and [UO 2 (NO 3 ) 2 (O 2 )] − . Multiple‐stage CID experiments reveal that the complexes dissociate in reactions that involve elimination of O 2 , NO 2 , or NO 3 , and subsequent reactions of interesting uranyl‐oxo product ions with (neutral) H 2 O and/or O 2 were investigated. Density functional theory (DFT) calculations reproduce experimental results and show that dissociation of nitrate ligands, with ejection of neutral NO 2 , is favored for both [UO 2 (NO 3 ) 3 ] − and [UO 2 (NO 3 ) 2 (O 2 )] − . DFT calculations also suggest that H 2 O adducts to products such as [UO 2 (O)(NO 3 )] − spontaneously rearrange to create dihydroxides and that addition of O 2 is favored over addition of H 2 O to formally U(V) species.