Cyclic amino(carboranyl) silylene: synthesis, structure and reactivity.
Hao Wang1, Tek Long Chan, Zuowei Xie
1Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. zxie@cuhk.edu.hk.
Chemical Communications (Cambridge, England)
|December 16, 2017
Summary
A novel carbene-stabilized cyclic silylene was synthesized and characterized. This strong sigma-donating molecule exhibits Lewis acid-base adduct formation and cycloaddition reactivity.
Area of Science:
- Organosilicon Chemistry
- Main Group Chemistry
- Carbene Chemistry
Background:
- Silylenes are silicon analogues of carbenes, featuring a divalent silicon atom.
- Stabilized silylenes are crucial for understanding silicon's reactivity and developing new silicon-based materials.
- Amino-substituted silylenes and carboranyl groups offer unique electronic and steric properties.
Purpose of the Study:
- To synthesize and characterize a novel carbene-stabilized cyclic amino(carboranyl) silylene.
- To investigate the electronic properties (sigma-donation and pi-acceptance) of the synthesized silylene.
- To explore the reactivity of the silylene in Lewis acid-base adduct formation and cycloaddition reactions.
Main Methods:
- Synthesis via reaction of cyclic amino(carboranyl) chlorosilane with N-heterocyclic carbene.
- Structural characterization using single-crystal X-ray diffraction.
- Electronic structure analysis using Density Functional Theory (DFT) calculations.
Main Results:
- Successful preparation and isolation of the carbene-stabilized cyclic amino(carboranyl) silylene.
- X-ray crystallography confirmed the molecular structure.
- DFT calculations revealed strong sigma-donating and weak pi-accepting capabilities.
- Demonstrated Lewis acid-base adduct formation with borane.
- Observed cycloaddition reactions with unsaturated molecules like diphenylacetylene and benzophenone.
Conclusions:
- The synthesized silylene is a potent sigma-donor, influencing its reactivity.
- The molecule's stability and unique electronic profile enable diverse chemical transformations.
- This work expands the scope of stabilized silylenes and their applications in synthesis.
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