Uranyl-Bound Tetra-Dentate Non-Innocent Ligands: Prediction of Structure and Redox Behaviour Using Density Functional Theory.
Chemphyschem
; 20(14): 1869-1878, 2019 Jul 16.
Article
en En
| MEDLINE
| ID: mdl-31063234
ABSTRACT
Computational methods have been applied to understand the reduction potentials of [UO2 -salmnt-L] complexes (L=pyridine, DMSO, DMF and TPPO), and their redox behavior is compared with previous experiments in dichloromethane solution. Since the experimental results were inconclusive regarding the influence of the uranyl-bound tetra-dentate 'salmnt' ligand, here we will show that salmnt acts as a redox-active ligand and exhibits non-innocent behavior to interfere with the otherwise expected one-electron metal (U) reduction. We have employed two approaches to determine the uranyl (VI/V) reduction potentials, using a direct study of one-electron reduction processes and an estimation of the overall reduction using isodesmic reactions. Hybrid density functional theory (DFT) methods were combined with the Conductor-like Polarizable Continuum Model (CPCM) to account for solvation effects. The computationally predicted one-electron reduction potentials for the range of [UO2 -salmnt-L] complexes are in excellent agreement with shoulder peaks (â¼1.4â
eV) observed in the cyclic voltammetry experiments and clearly correlate with ligand reduction. Highly conjugated pi-bonds stabilize the ligand based delocalized orbital relative to the localized U f-orbitals, and as a consequence, the ligand traps the incoming electron. A second reduction step results in metal U(VI) to U(V) reduction, in good agreement with the experimentally assigned uranyl (VI/V) reduction potentials.
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MEDLINE
Tipo de estudio:
Prognostic_studies
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Risk_factors_studies
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En
Revista:
Chemphyschem
Asunto de la revista:
BIOFISICA
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QUIMICA
Año:
2019
Tipo del documento:
Article
País de afiliación:
Reino Unido