Inorganic Chemistry 2015-03-16

A ligand field series for the 4f-block from experimental and DFT computed Ce(IV/III) electrochemical potentials.

Justin A Bogart, Andrew J Lewis, Michael A Boreen, Heui Beom Lee, Scott A Medling, Patrick J Carroll, Corwin H Booth, Eric J Schelter

Index: Inorg. Chem. 54(6) , 2830-7, (2015)

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Abstract

Understanding of the sensitivity of the reduction potential of cerium(IV) cations to ligand field strength has yet to benefit from systematic variation of the ligand environment. Detailed analyses for a series of seven cerium(IV) tetrakis(pyridyl-nitroxide) compounds and their cerium(III) analogues in varying ligand field strengths are presented. Electrochemical, spectroscopic, and computational results reveal a close correlation of electronic properties with ligand substituents. Together with electrochemical data for reported eight-coordinate compounds, DFT calculations reveal a broad range of the cerium(IV/III) redox potentials correlated to ligand field strengths, establishing a semiempirical, predictive model for the modulation of cerium redox thermodynamics and ligand field strengths. Applications over a variety of scientific disciplines make use of the fundamental redox thermodynamics of cerium. Such applications will benefit from a combined experimental and theoretical approach for assessing redox cycling of cerium compounds.