1. Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene.
- Author
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Thakur, Sandeep Kumar, Roig, Nil, Monreal‐Corona, Roger, Langer, Jens, Alonso, Mercedes, and Harder, Sjoerd
- Subjects
RARE earth metals ,BENZENE ,SANDWICH construction (Materials) ,MAGNETIC susceptibility ,NUCLEAR magnetic resonance spectroscopy ,OXIDATION states - Abstract
Inverse sandwich complexes of Yb and Sm stabilized by a bulky β‐diketiminate (BDI) ligand have been prepared: (BDI)Ln(η6,η6‐C6H6)Ln(BDI); Ln=lanthanide. Coordinated benzene ligands can be neutral, di‐anionic or, often controversially discussed, even tetra‐anionic. The formal charge on benzene is correlated to assignment of the metal oxidation state which generally poses a problem. Herein, we take advantage of the structural similarities found when comparing CaII with YbII, and SrII with SmII complexes. In this work, we found an excellent overlap of the Ca/Yb inverse sandwich structures but a striking difference for the Sr/Sm pair. The much shorter Sm−N and Sm‐C6H6 distances are strong evidence for a SmIII‐benzene−4‐SmIII assignment. This was further supported by NMR spectroscopy, magnetic susceptibility, reactivity and comprehensive computational investigation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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