Fragmentation of gas-phase actinide coordination complexes presents opportunities to access new types of transformations and bonding that may be elusive or inaccessible in condensed phase due to interactions with neighboring atoms or molecules. Gas-phase complexes with ligands tailored to exhibit particular types of transformations or fragmentations are produced by electrospray ionization of solutions containing the metal ion and one or more ligands. A particular focus is on actinyl anion complexes, AnO2(L)3-, where An = U, Np or Pu, and L is an anion ligand, one example being acetate, L- = CH3CO2-. Fragmentation of the complex in a quadrupole ion trap is achieved by collision induced dissociation, in which the ion undergoes multiple energetic collisions with helium atoms; products are identified by mass-selective ejection from the trap. For strongly bound ligands with sufficiently facile fragmentation pathways, formation of new complexes via elimination of a neutral molecule, for example CO2 from acetate, can dominate over straightforward ligand loss. This gas-phase synthetic approach has resulted in the production of novel organoactinyl complexes, and the previously elusive transformation of a uranyl oxo bond to a nitrido bond. Computational studies provide information on the mechanisms of the transformations, and the structures and bonding of the species involved in the observed processes. Insights into gas-phase transformations provided by experiment and theory can contribute to the development of new condensed phase synthetic schemes.

Accessing new actinide chemistry by fragmentation of gas-phase coordination complexes

247th National Meeting (2014)

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