Type of carbene demonstrating particular stability
1,3-Dimesityl-imidazol-4,5-dihydro-2-ylidene, a representative persistent carbene
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. The best-known examples and by far largest subgroup are the N-heterocyclic carbenes (NHC)[1] (sometimes called Arduengo carbenes), in which nitrogen atoms flank the formal carbene.
Modern theoretical analysis suggests that the term "persistent carbene" is in fact a misnomer. Persistent carbenes do not in fact have a carbene electronic structure in their ground state, but instead an ylide stabilized by aromatic resonance or steric shielding. Excitation to a carbene structure then accounts for the carbene-like dimerization that some persistent carbenes undergo over the course of days.
Persistent carbenes in general, and Arduengo carbenes in particular, are popular ligands in organometallic chemistry.
^Hopkinson, M. N.; Richter, C.; Schedler, M.; Glorius, F. (2014). "An Overview of N-Heterocyclic Carbenes". Nature. 510 (7506): 485–496. Bibcode:2014Natur.510..485H. doi:10.1038/nature13384. PMID 24965649. S2CID 672379.
and 19 Related for: Persistent carbene information
A persistentcarbene (also known as stable carbene) is an organic molecule whose natural resonance structure has a carbon atom with incomplete octet (a...
exception are the persistentcarbenes, which have extensive application in modern organometallic chemistry. There are two common methods for carbene generation...
transition metal carbene complex is an organometallic compound featuring a divalent carbon ligand, itself also called a carbene. Carbene complexes have...
with a carbene precursor. An early pioneer was Christoph Grundmann reporting on a carbene dimerisation in 1938. In the domain of persistentcarbenes the...
National Hockey Center in St. Cloud, Minnesota N-Heterocyclic carbene, a persistentcarbene, commonly used as ligand in organometallic chemistry Nearly...
Retrieved January 7, 2007. A. J. Arduengo (1976). "Looking for Stable Carbenes: The Difficulty in Starting Anew". Accounts of Chemical Research. 32 (11):...
nitrogens) would yield the carbene dihydroimidazol-2-ylidene. Derivatives of the latter comprise an important class of persistentcarbenes. Classified as a diamine...
of vitamin B1: This was the first evidence for the existence of persistentcarbenes. Furoin has been used as a plasticizer. Denis Lorient (1999), New...
(R2Sn:) are a class of organotin(II) compounds that are analogues of carbene. Unlike carbene, which usually has a triplet ground state, stannylenes have a singlet...
in hydroboration, organometallic chemistry, chiral materials and persistentcarbenes. In 2010 Crudden became head of a Natural Sciences and Engineering...
Stable and persistent phosphorus radicals are phosphorus-centred radicals that are isolable and can exist for at least short periods of time. Radicals...
Grubbs, a CRD consultant, for the metathesis work. Anthony Arduengo’s persistentcarbenes opened up a new area of chemistry and they have proven to be important...
species are usually encountered only as transient intermediates. However, persistent alkyl radicals with half-lives "from seconds to years" have been prepared...
The premier example is difluorocarbene, CF2, which is a singlet whereas carbene (CH2) has a triplet ground state. This difference is significant because...
compounds include both stannylenes (formula: R2Sn, as seen for singlet carbenes) and distannylenes (R4Sn2), which are roughly equivalent to alkenes. Both...
that unstable phosphasilene can react with DMAP and small N-heterocyclic carbene (NHC) to afford the corresponding stable complexes. In phosphasilenes stabilized...
with Richard R. Schrock describing living polymerization with a tungsten carbene complex. Generally, ROMP reactions involve the conversion of a cyclic olefin...
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