These species may be called "foiled" when they are stabilized by a nearby double bond.
These species may be called "foiled" when they are stabilized by a nearby double bond. When Tebbe's reagent reacts with a Lewis base, it forms one of these. Imidazole-2-ylidenes are among the stable examples of these molecules, which can exist in Wanzlick equilibrium with their dimers, and which were first isolated in crystalline form by Anthony Arduengo. Those stable molecules of this type are called "persistent." These molecules can be formed by photolysis of diazirines or diazoalkanes. Saturated N-heterocyclic types of these are combined with a ruthenium complex in 2nd generation Grubbs' catalysts. If a metal bonded to one of these molecules bears an electron-withdrawing group, the result is named for Fischer; if it is bonded to an electron-donating group, it is named for Schrock. For 10 points, name these molecules found in singlet and triplet states, in which a neutral, divalent carbon atom has two unshared electrons.
These species may be called "foiled" when they are stabilized by a nearby double bond.
carbenes