Collision-induced dissociation of [UO (NO ) ] and [UO (NO ) (O )] and reactions of product ions with H O and O

Amanda R. Bubas, Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania, USA.
Evan Perez, Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania, USA.
Luke J. Metzler, Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania, USA.
Scott D. Rissler, Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania, USA.
Michael J. Van Stipdonk, Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania, USA.

Abstract

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