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Updated: May 8, 2026

Catalytic Scavenging of Plant Reactive Oxygen Species In Vivo by Anionic Cerium Oxide Nanoparticles
Published on: August 26, 2018
Homoleptic cerium(III) and cerium(IV) nitroxide complexes: significant stabilization of the 4+ oxidation state
Justin A Bogart1, Andrew J Lewis, Scott A Medling
1P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
Abstract:
Electrochemical experiments performed on the complex Ce(IV)[2-((t)BuNO)py]4, where [2-((t)BuNO)py](-) = N-tert-butyl-N-2-pyridylnitroxide, indicate a 2.51 V stabilization of the 4+ oxidation state of Ce compared to [(n)Bu4N]2[Ce(NO3)6] in acetonitrile and a 2.95 V stabilization compared to the standard potential for the ion under aqueous conditions. Density functional theory calculations suggest that this preference for the higher oxidation state is a result of the tetrakis(nitroxide) ligand framework at the Ce cation, which allows for effective electron donation into, and partial covalent overlap with, vacant 4f orbitals with δ symmetry. The results speak to the behavior of CeO2 and related solid solutions in oxygen uptake and transport applications, in particular an inherent local character of bonding that stabilizes the 4+ oxidation state. The results indicate a cerium(IV) complex that has been stabilized to an unprecedented degree through tuning of its ligand-field environment.
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