Angewandte Chemie International Edition
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Back Cover: Conversion of a Singlet Silylene to a stable Biradical (Angew. Chem. Int. Ed. 6/2013)
Colored stable biradicals are described by H. W. Roesky, G. Frenking, I. Tkach, D. Stalke, and co-workers in their Communication on page 1801 ff.; they were prepared from SiCl2, which is stabilized by an N-heterocyclic carbene, and a cyclic alkyl(amino)carbene. The deep-blue crystals of one polymorph of the product are stable upon exposure to air for about a week, while the solution in THF decomposes rapidly when exposed to air. A C-C bond formation can be observed in a side reaction of the synthesis.