Redox behavior of gas phase Pu(IV)-monodentate ligand complexes: an investigation by electrospray ionization mass spectrometry

This study reports the gas phase complexation behavior of Pu(IV) with N,N-dialkylamide ligands and tributylphosphate by electrospray ionization mass spectrometry. In-source collision induced dissociation (CID) and ion trap collision induced dissociation were used to investigate the kinetic stability of Pu species in the gas phase. With both class of ligands, N,N-dialkylamide and trialkylphosphate, oxidation of Pu from the tetravalent state to the hexavalent state was observed at both high skimmer voltages and during ion trap CID. The results suggest that oxidation is due to the presence of a nitrate group in the coordination sphere of the metal and is independent of the ligand.