• biradicals;
  • cyclic alkyl(amino)carbenes;
  • EPR spectroscopy;
  • N-heterocyclic carbenes;
  • singlet silylenes
Thumbnail image of graphical abstract

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[BOND]C bond formation can be observed in a side reaction of the synthesis.