A Ligand Field Series for the 4f-Block from Experimental and DFT Computed Ce(IV/III) Electrochemical Potentials

• Published in: Inorganic chemistry Vol. 54; no. 6; pp. 2830 - 2837
• Main Authors: Bogart, Justin A, Lewis, Andrew J, Boreen, Michael A, Lee, Heui Beom, Medling, Scott A, Carroll, Patrick J, Booth, Corwin H, Schelter, Eric J
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 16.03.2015
• Subjects: Cerium compounds; Computation; Correlation; Electrode potentials; Field strength; Ligands; Mathematical models; Thermodynamics
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic503000z

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.