title: Experimental and theoretical studies on the fragmentation of gas-phase uranyl-, neptunyl-, and plutonyl-diglycolamide complexes.
abstract: Fragmentation of actinyl(VI) complexes U(VI)O2(L)2(2+), Np(VI)O2(L)2(2+), and Pu(VI)O2(L)2(2+) (L = tetramethyl-3-oxa-glutaramide, TMOGA) produced by electrospray ionization was examined in the gas phase by collision induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Cleavage of the C-O(ether) bond was observed for all three complexes, with dominant products being U(VI)O2(L)(L-86)(+) with charge reduction, and Np(VI)O2(L)(L-101)(2+) and Pu(VI)O2(L)(L-101)(2+) with charge conservation. The neptunyl and plutonyl complexes also exhibited substantial L(+) loss to give pentavalent complexes Np(V)O2(L)(+) and Pu(V)O2(L)(+), whereas the uranyl complex did not, consistent with the comparative An 5f-orbital energies and the An(VI)O2(2+)/An(V)O2(+) (An = U, Np, Pu) reduction potentials. CID of Np(V)O2(L)2(+) and Pu(V)O2(L)2(+) was dominated by neutral ligand loss to form Np(V)O2(L)(+) and Pu(V)O2(L)(+), which hydrated by addition of residual water in the ion trap; U(V)O2(L)2(+) was not observed. Theoretical calculations of the structures and bonding of the An(VI)O2(L)2(2+) complexes using density functional theory reveal that the metal centers are coordinated by six oxygen atoms from two TMOGA ligands.
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Gong
authors.forename: Han-Shi
authors.initials: HS
authors.lastname: Hu
authors.forename: Linfeng
authors.initials: L
authors.lastname: Rao
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: John K
authors.initials: JK
authors.lastname: Gibson