Magnesium-halobenzene bonding: mapping the halogen sigma-hole with a Lewis-acidic complex

Friedrich A, Pahl J, Eyselein J, Langer J, van Eikema Hommes N, Görling A, Harder S (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Chemical Science Royal Society of Chemistry

Book Volume: 12

Pages Range: 2410-2418

Journal Issue: 7

DOI: 10.1039/d0sc06321e

Abstract

Complexes of the Lewis base-free cations (MeBDI)Mg+and (tBuBDI)Mg+with Ph-X ligands (X = F, Cl, Br, I) have been studied (MeBDI = HC[C(Me)N-DIPP]2andtBuBDI = HC[C(tBu)N-DIPP]2; DIPP = 2,6-diisopropylphenyl). For the smaller β-diketiminate ligand (MeBDI) only complexes with PhF could be isolated. Heavier Ph-X ligands could not compete with bonding of Mg to the weakly coordinating anion B(C6F5)4−. For the cations with the bulkiertBuBDI ligand, the full series of halobenzene complexes was structurally characterized. Crystal structures show that the Mg⋯X-Ph angle strongly decreases with the size of X: F 139.1°, Cl 101.4°, Br 97.7°, I 95.1°. This trend, which is supported by DFT calculations, can be explained with the σ-hole which increases from F to I. Charge calculation and Atoms-In-Molecules analyses show that Mg⋯F-Ph bonding originates from electrostatic attraction between Mg2+and the very polar Cδ+-Fδ−bond. For the heavier halobenzenes, polarization of the halogen atom becomes increasingly important (Cl < Br < I). Complexation with Mg leads in all cases to significant Ph-X bond activation and elongation. This unusual coordination of halogenated species to early main group metals is therefore relevant to C-X bond breaking.

Authors with CRIS profile

Alexander Friedrich Lehrstuhl für Anorganische und Metallorganische Chemie Jürgen Pahl Lehrstuhl für Anorganische und Metallorganische Chemie Jonathan Mai Lehrstuhl für Anorganische und Metallorganische Chemie Jens Langer Lehrstuhl für Anorganische und Metallorganische Chemie Nicolaas van Eikema Hommes Lehrstuhl für Theoretische Chemie Andreas Görling Lehrstuhl für Theoretische Chemie Sjoerd Harder Lehrstuhl für Anorganische und Metallorganische Chemie

How to cite

APA:

Friedrich, A., Pahl, J., Eyselein, J., Langer, J., van Eikema Hommes, N., Görling, A., & Harder, S. (2021). Magnesium-halobenzene bonding: mapping the halogen sigma-hole with a Lewis-acidic complex. Chemical Science, 12(7), 2410-2418. https://doi.org/10.1039/d0sc06321e

MLA:

Friedrich, Alexander, et al. "Magnesium-halobenzene bonding: mapping the halogen sigma-hole with a Lewis-acidic complex." Chemical Science 12.7 (2021): 2410-2418.

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