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Brominated [20]silafulleranes: pushing the limits of steric loading
Marcel Bamberg1, Thomas Gasevic2, Michael Bolte1
1Institut 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.
Chemical Communications (Cambridge, England)
|May 31, 2023
Summary
Researchers synthesized novel brominated silafulleranes from perhydrogenated silafullerane using boron tribromide. This method allows for regioselective derivatization of the silicon framework, yielding partially and exhaustively brominated clusters.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Nanotechnology
Background:
- Silafulleranes are silicon-based analogs of carbon fullerenes.
- Functionalization of silafullerane cages is crucial for tuning their properties.
- Controlled synthesis of substituted silafulleranes remains a challenge.
Purpose of the Study:
- To develop a regioselective method for brominating silafulleranes.
- To synthesize partially and exhaustively brominated silafullerane derivatives.
- To investigate the impact of bromination on the silafullerane framework.
Main Methods:
- Treatment of perhydrogenated silafullerane [nBu4N][Cl@Si20(SiH3)12H8] with boron tribromide (BBr3).
- Varying BBr3 equivalents, temperature, and reaction time to control bromination extent.
- Partial Br/H exchange using diisobutylaluminum hydride (iBu2AlH).
Main Results:
- Synthesized partially brominated [nBu4N][Cl@Si20(SiBr2H)12Br8] using 120 eq. BBr3 at room temperature.
- Synthesized exhaustively brominated [nBu4N][Cl@Si20(SiBr3)12Br8] using 300 eq. BBr3 at 130 °C.
- Achieved regioselective derivatization of the Si32 framework under mild conditions.
- Obtained [nBu4N][Cl@Si20(SiH3)12Br8] via partial Br/H exchange.
Conclusions:
- Boron tribromide is an effective reagent for controlled bromination of silafulleranes.
- Reaction conditions dictate the degree of bromination and regioselectivity.
- Steric strain influences the derivatization of the silafullerane surface.
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