No abstract

R2P̈‐C̈‐X or R2P⊕  C⊖‐X or R2PC‐X—which form best describes the activity of the title compound 1? On the basis of its reactions with Me3SiCl, Me3SiN3 and DMSO as well as NMR data, 1 was hitherto regarded as a species with PC multibonding. That 1 is rather a carbene, could now be deduced, inter alia, from the addition of electron deficient alkenes (→2) and tert‐butyl isocyanide (→3) (R=iPr2N, X = SiMe3).

Neutral but versatile: N‐heterocyclic carbenes are very efficient catalysts for the group‐transfer polymerization of acrylates and methacrylates in both polar and apolar media. These organocatalysts were also used to design all‐(meth)acrylic di‐ and triblock copolymers.

A stable diphosphorus analogue of Enders' N‐heterocyclic carbene has been prepared by taking advantage of the inherent π‐donor capabilities of phosphorus, which are as good as, or better than, those of nitrogen. The P‐heterocyclic carbene (see figure; C gray, N blue, P red) behaves as a strong donor ligand and forms transition‐metal complexes that are thermally and air stable.