Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene

Sandeep Kumar Thakur; Nil Roig; Roger Monreal‐Corona; Jens Langer; Mercedes Alonso; Sjoerd Harder

doi:10.1002/anie.202405229

Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene

Sandeep Kumar Thakur, Nil Roig, Roger Monreal‐Corona, Jens Langer, Mercedes Alonso, Sjoerd Harder

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

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.

Original language	English
Article number	e202405229
Journal	Angewandte Chemie International Edition
Volume	63
Issue number	25
DOIs	https://doi.org/10.1002/anie.202405229
Publication status	Published - 17 Jun 2024

Bibliographical note

Funding Information:
We acknowledge Dr. Daniel Santalucia (Max\u2010Planck\u2010Institut f\u00FCr Kohlenforschung, M\u00FClheim, Germany) for measurement of the magnetic susceptibilities of \u2010Sm. M.A. thanks the Vrije Universiteit Brussel (VUB) for financial support through a Strategic Research Program awarded to the ALGC research group. N.R. acknowledges funding from the EUTOPIA alliance through a co\u2010tutelle studentship. R.M.\u2010C. thanks the Government of Spain for the pre\u2010doctoral fellowship FPU20/00707 and the mobility EST23/00507. The computational investigation was partially supported by the supercomputing infrastructure of the NLHPC (ECM\u201002) and the VSC (Flemish Supercomputer Center), funded by the Research Foundation\u2013Flanders (FWO) and the Flemish Government. Open Access funding enabled and organized by Projekt DEAL. 3

Publisher Copyright:
© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

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title = "Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene",

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.",

author = "Thakur, {Sandeep Kumar} and Nil Roig and Roger Monreal‐Corona and Jens Langer and Mercedes Alonso and Sjoerd Harder",

note = "Funding Information: We acknowledge Dr. Daniel Santalucia (Max\u2010Planck\u2010Institut f\u00FCr Kohlenforschung, M\u00FClheim, Germany) for measurement of the magnetic susceptibilities of \u2010Sm. M.A. thanks the Vrije Universiteit Brussel (VUB) for financial support through a Strategic Research Program awarded to the ALGC research group. N.R. acknowledges funding from the EUTOPIA alliance through a co\u2010tutelle studentship. R.M.\u2010C. thanks the Government of Spain for the pre\u2010doctoral fellowship FPU20/00707 and the mobility EST23/00507. The computational investigation was partially supported by the supercomputing infrastructure of the NLHPC (ECM\u201002) and the VSC (Flemish Supercomputer Center), funded by the Research Foundation\u2013Flanders (FWO) and the Flemish Government. Open Access funding enabled and organized by Projekt DEAL. 3 Publisher Copyright: {\textcopyright} 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.",

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Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene. / Thakur, Sandeep Kumar; Roig, Nil; Monreal‐Corona, Roger; Langer, Jens; Alonso, Mercedes; Harder, Sjoerd.

In: Angewandte Chemie International Edition, Vol. 63, No. 25, e202405229, 17.06.2024.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene

AU - Thakur, Sandeep Kumar

AU - Roig, Nil

AU - Monreal‐Corona, Roger

AU - Langer, Jens

AU - Alonso, Mercedes

AU - Harder, Sjoerd

N1 - Funding Information: We acknowledge Dr. Daniel Santalucia (Max\u2010Planck\u2010Institut f\u00FCr Kohlenforschung, M\u00FClheim, Germany) for measurement of the magnetic susceptibilities of \u2010Sm. M.A. thanks the Vrije Universiteit Brussel (VUB) for financial support through a Strategic Research Program awarded to the ALGC research group. N.R. acknowledges funding from the EUTOPIA alliance through a co\u2010tutelle studentship. R.M.\u2010C. thanks the Government of Spain for the pre\u2010doctoral fellowship FPU20/00707 and the mobility EST23/00507. The computational investigation was partially supported by the supercomputing infrastructure of the NLHPC (ECM\u201002) and the VSC (Flemish Supercomputer Center), funded by the Research Foundation\u2013Flanders (FWO) and the Flemish Government. Open Access funding enabled and organized by Projekt DEAL. 3 Publisher Copyright: © 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

PY - 2024/6/17

Y1 - 2024/6/17

N2 - 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.

AB - 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.

UR - https://doi.org/10.1002/anie.202405229

U2 - 10.1002/anie.202405229

DO - 10.1002/anie.202405229

M3 - Article

VL - 63

JO - Angewandte Chemie International Edition

JF - Angewandte Chemie International Edition

SN - 1433-7851

IS - 25

M1 - e202405229

ER -

Similarities and Differences in Benzene Reduction with Ca, Sr, Yb and Sm: Strong Evidence for Tetra‐Anionic Benzene

Abstract

Bibliographical note

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