Brominated [20]silafulleranes: pushing the limits of steric loading

Marcel Bamberg; Thomas Gasevic; Michael Bolte; Alexander Virovets; Hans-Wolfram Lerner; Stefan Grimme; Markus Bursch; Matthias Wagner

doi:10.1039/d3cc02142d

Brominated [20]silafulleranes: pushing the limits of steric loading

Chem Commun (Camb). 2023 Jun 13;59(48):7459-7462. doi: 10.1039/d3cc02142d.

Authors

Marcel Bamberg¹, Thomas Gasevic², Michael Bolte¹, Alexander Virovets¹, Hans-Wolfram Lerner¹, Stefan Grimme², Markus Bursch³, Matthias Wagner¹

Affiliations

¹ Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany. matthias.wagner@chemie.uni-frankfurt.de.
² Mulliken Center for Theoretical Chemistry, Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstraße 4, 53115 Bonn, Germany.
³ Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.

PMID: 37254708
DOI: 10.1039/d3cc02142d

Abstract

Starting from the perhydrogenated silafullerane [nBu₄N][Cl@Si₂₀(SiH₃)₁₂H₈], treatment with BBr₃ leads to partially and exhaustively brominated clusters, [nBu₄N][Cl@Si₂₀(SiBr₂H)₁₂Br₈] (120 eq. BBr₃, room temperature, 30 min) and [nBu₄N][Cl@Si₂₀(SiBr₃)₁₂Br₈] (300 eq. BBr₃, 130 °C, 3 d). Perbromination is accompanied by a massively increased steric strain on the cluster surface, which explains why our approach achieves regioselective derivatization of the Si₃₂ framework when mild conditions are maintained. Partial Br/H exchange on [nBu₄N][Cl@Si₂₀(SiBr₂H)₁₂Br₈] (30 eq. iBu₂AlH, room temperature, 16 h) affords [nBu₄N][Cl@Si₂₀(SiH₃)₁₂Br₈].