Conversion of a Singlet Silylene to a stable Biradical


  • H.W.R. thanks the Deutsche Forschungsgemeinschaft for financial support (RO 224/60-1). D.S. thanks the DNRF funded “Centre of Materials Crystallography” and the doctoral programme “Catalysis for Sustainable Synthesis”, provided by the Land Niedersachsen. We thank Prof. Marina Bennati for EPR analyses, Prof. F. Meyer and Dr. S. Demeshko for magnetic investigations, and S. Neudeck for UV/Vis measurements.


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Silicon becomes colored: Stable biradicals were prepared from an N-heterocyclic carbene stabilized SiCl2 and a cyclic alkyl(amino)carbene, and characterized as two polymorphs. The deep-blue crystals of one polymorph are stable upon exposure to air for about a week, while the solution in THF decomposes rapidly when exposed to air. In a side reaction, the different carbene species react with each other under C[BOND]H activation and C[BOND]C bond formation in the presence of the biradical.