The coordination of amidoxime ligands with uranyl in the gas phase: a mass spectrometry and DFT study

Abstract

Sequestering uranium from the ocean is a promising solution to fulfill the demand for nuclear energy. Motivated by this purpose, a series of amidoxime ligands and their analogs have been developed with high absorption capacity and selectivity. An in-depth understanding of the structural information of the uranyl-ligand complexes is essential to improve the performance of the ligands. Herein, we have studied the coordination of three amidoxime ligands (6-methoxyl-naphtha-2-amidoxime, NAO; glutarimidedioxime, GIO; and gluardiamidoxime, GDO) with uranyl in the gas phase by mass spectrometry. The identifications of the electrospray ionization (ESI) generated species, the fragmentation pathways upon dissociation, the relative binding affinities of the ligands, and the hydration reactions have been conducted and compared to reveal their structural information in the gas phase. The binding modes for all the complexes were suggested based on the experimental results and were further studied by density functional theory (DFT) calculations.

Complexation of Manganese with Glutarimidedioxime: Implication for Extraction Uranium from Seawater

“…With the same collision energy, the 1:2 Mn/A complex fragment into 1: 1 Mn/A complex at m/z of 197, as well as the other of the fragment ions due to the fragmentation of the ligand itself such as dehydration reactions so that the binding between the ligands and manganese ion were retained as large as possible. Although the quantitative speciation of the solution by MS is difficulty, these results indicate the consistency between the aqueous phase and the gas phase2425.…”

The enhanced uranyl–amidoxime binding by the electron-donating substituents

“…1) using Pd catalyst 14 and investigated their complexion (AO2-AO4) with uranyl by density functional theory (DFT) calculations 15 and mass spectrometric experiments. 16 The synthetic strategy allows us to investigate the aforementioned substitutive effect by providing a series of AO derivatives. In this study, selected AO ligands bearing different substituent groups were studied.…”

“…The 1 : 2 complexes, i.e., [UO 2 (AO) 2 (NO 3 )] + demonstrates stronger MS signals than the 1 : 1 or 1 : 3 complexes across the AO ligand series because the equatorial plane of uranyl in 1 : 2 complexes was saturated with the most stable h 2 binding mode of AO; 18 however, it was unsaturated in 1 : 1 complexes or partially ligated by AO with the less stable h 1 binding mode. 16 Note that uranyl-AO5 complexes show a much poorer MS intensity; hence, they were not further experimentally investigated.…”

“…the loss of nitric acid or the loss of AO ligand, the rst pathway was predominant. 16 Consequently, the D.E. of these complexes mainly reected the binding between uranyl and nitrate.…”

Collision‐induced dissociation of [UVIO2(ClO4)]+ revisited: Production of [UVIO2(Cl)]+ and subsequent hydrolysis to create [UVIO2(OH)]+

“…outside the influence of solvent or other condensed phase effects) in a species‐specific fashion . Since then, ESI has been used to create gas‐phase uranyl species for a range of tandem mass spectrometry (MS/MS), anion photoelectron spectroscopy, and ion mobility studies . ESI and MS/MS have also been used to study and compare the intrinsic dissociation and ion‐molecule reactions of transuranic species …”