Metal versus Ligand Reduction in Ln3+ Complexes of a Mesitylene-Anchored Tris(Aryloxide) Ligand

Chad T. Palumbo, Dominik P. Halter, Vamsee K. Voora, Guo P. Chen, Alan K. Chan, Megan E. Fieser, Joseph W. Ziller, Wolfgang Hieringer, Filipp Furche, Karsten Meyer, William J. Evans

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18 Scopus citations

Abstract

The synthesis of 4fn Ln3+ complexes of the tris(aryloxide) mesitylene ligand, ((Ad,MeArO)3mes)3-, with Ln = La, Ce, Pr, Sm, and Yb, and their reduction with potassium have revealed that this ligand system can be redox active with some metals. Protonolysis of [Ln(N(SiMe3)2)3] (Ln = La, Ce, Pr, Sm, Yb) with the tris(phenol) (Ad,MeArOH)3mes yielded the Ln3+ complexes [((Ad,MeArO)3mes)Ln] (Ln = La, Ce, Pr, Sm, Yb), 1-Ln. Single electron reduction of each 4fn complex, 1-Ln, using potassium yielded the reduced products, [K(2.2.2-cryptand)][((Ad,MeArO)3mes)Ln] (Ln = La, Ce, Pr, Sm, Yb), 2-Ln. The Sm and Yb complexes have properties consistent with the presence of Ln2+ ions with traditional 4fn+1 electron configurations. However, the La, Ce, and Pr complexes appear to formally contain Ln3+ ions and ((Ad,MeArO)3mes)4- ligands. Structural comparisons of the [((Ad,MeArO)3mes)Ln] and [((Ad,MeOAr)3mes)Ln]1- complexes along with UV-vis absorption and EPR spectroscopy as well as density functional theory calculations support these ground state assignments.

Original languageEnglish (US)
Pages (from-to)2823-2833
Number of pages11
JournalInorganic chemistry
Volume57
Issue number5
DOIs
StatePublished - Mar 5 2018

Bibliographical note

Funding Information:
We thank the U.S. National Science Foundation for support of the theoretical studies (CHE-1464828 to F.F.) and the experimental studies (CHE-1565776 to W.J.E.). We also thank Professor Arnold Rheingold, Dr. Milan Gembicky, Dr. Jason R. Jones, and Dr. Jordan F. Corbey for assistance with X-ray crystallography and Professor A. S. Borovik for spectroscopic assistance. We also thank the NSF for providing graduate fellowship support for C.T.P. (DGE-1321846). D.P.H. acknowledges the Graduate School Molecular Science (GSMS) of FAU Erlangen-Nürnberg for generous support. The Bundesministerium für Bildung und Forschung (BMBF, support codes 02NUK012C and 02NUK020C), the FAU Erlangen-Nürnberg, the Deutsche Forschungsgemeinschaft (DFG) and the Cluster of Excellence EXC 315 “Engineering of Advanced Materials” (www.eam.uni-erlangen.de), and COST Action CM1006 are acknowledged for funding.

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