Search results
Results from the WOW.Com Content Network
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more
Carbene radicals, in which the carbene is bonded to an open-shell metal with the carbene carbon possessing a radical character. Carbene radicals have features of both Fischer and Schrock carbenes, but are typically long-lived reaction intermediates. The "second generation" of the Grubbs catalysts for alkene metathesis features an NHC ligand.
Carbene complexes have been synthesized from most transition metals and f-block metals, [2] using many different synthetic routes such as nucleophilic addition and alpha-hydrogen abstraction. [1] The term carbene ligand is a formalism since many are not directly derived from carbenes and most are much less reactive than lone carbenes. [2]
A persistent carbene (also known as stable carbene) is an organic molecule whose natural resonance structure has a carbon atom with incomplete octet (a carbene), but does not exhibit the tremendous instability typically associated with such moieties.
A carbene is a neutral molecule containing a divalent carbon with six electrons in its valence shell. Due to this, carbenes are highly reactive electrophiles and generated as reaction intermediates. [9] A singlet carbene contains an empty p orbital and a roughly sp 2 hybrid orbital that has two electrons.
The structure of carbodicarbenes greatly resembles that of carbodiphosphoranes. [4] Computational data for a N-methyl-substituted carbodicarbene predicted a carbon-carbon bond with a length only marginally longer than a C=C bond in a typical allene at 1.358 Å (compared with 1.308 Å for allene), but with a significantly bent bond angle of 131.8° (compared to 180° for a standard linear ...
Carbyne molecules are generally found to be in electronic doublet states: the non-bonding electrons on carbon are arranged as one radical (unpaired electron) and one electron pair, leaving a vacant atomic orbital, rather than being a triradical (the quartet state).
A Fischer carbene is a type of transition metal carbene complex, which is an organometallic compound containing a divalent organic ligand. In a Fischer carbene, the carbene ligand is a σ-donor π-acceptor ligand. Because π-backdonation from the metal centre is generally weak, the carbene carbon is electrophilic.