Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra-Anionic Benzene.
Angew Chem Int Ed Engl
; 63(25): e202405229, 2024 Jun 17.
Article
em En
| MEDLINE
| ID: mdl-38613386
ABSTRACT
Inverse sandwich complexes of Yb and Sm stabilized by a bulky ß-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.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2024
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Article