Defined as neutral four-electron valence shell, carbenes are an intriguing class of carbon-containing species. Their incomplete electron octet and coordinative unsaturation, however, render free carbenes inherently unstable and they have been traditionally considered only as highly reactive transient intermediates in organic transformations.1 Synthesis of the first N-heterocyclic carbene (NHC) 1,3-di(adamantyl)imidazol-2-ylidene led to an explosion of experimental and theoretical studies with libraries of novel NHCs being synthesized and analysed.2
