Carbene Isolation
Carbene Isolation - Related Videos
10:44
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
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Cited by 5 •
2019
We present protocols for the isolation of stable heterocyclic carbenes. The synthesis of a cyclic (alkyl)(amino) carbene (CAAC) and an N-heterocyclic carbene (NHC) is demonstrated using filter cannulas and Schlenk technique. We furthermore present the synthesis of the related oxygen-sensitive, electron-rich mixed “Wanzlick dimer” and the reduced stable organic radical.
14:07
Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus
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Cited by 2 •
2014
Here, we present a protocol for the synthesis of two carbonyl-decorated carbenes. The protocol makes these interesting compounds readily available to chemists of all skill levels. In addition to the synthesis of these two carbenes, their use in the activation of white phosphorus is also described.
12:19
Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
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Cited by 2 •
2018
We describe a protocol to photogenerate N-heterocyclic carbenes (NHCs) by UV irradiation of a 2-isopropylthioxanthone/imidazolium tetraphenylborate salt system. Methods to characterize the photoreleased NHC and elucidate the photochemical mechanism are proposed. The protocols for ring-opening metathesis photopolymerization in solution and miniemulsion illustrate the potential of this 2-component NHC photogenerating system.
19:58
Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
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Cited by 1 •
2017
Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.
08:09
Vasodilation of Isolated Vessels and the Isolation of the Extracellular Matrix of Tight-skin Mice
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Cited by 1 •
2017
We describe the isolation of cardiac extracellular matrix from C57Bl/6J control mice, tight-skin mice, and tight-skin mice treated with the IRF5 inhibitory peptide. We also describe the vasodilation studies on the isolated vessels from C57Bl/6J, tight-skin mice and tight-skin mice treated with the IRF5 inhibitory peptide.
FAQs
Bulky substituents protect the reactive carbon by shielding it from potential reaction partners and from pathways leading to decomposition or dimerization. Electronic effects, in contrast, influence whether the carbene is stabilized in a singlet or triplet state. Together, these design features determine whether a species can persist long enough for isolation and study.
The spin state is a central electronic property of an isolated carbene, not merely a structural label. Carbene isolation makes it possible to examine whether a prepared species adopts singlet or triplet character and to relate that state to its observed reactivity. This direct access distinguishes persistent compounds from fleeting intermediates normally detected only during reactions.
Stable N-heterocyclic carbenes, or NHCs, are especially valuable because they do more than provide isolable examples of unusual carbon bonding. Their persistent frameworks can serve as ligands for transition metals, helping create metal-containing catalytic systems, and as organocatalysts in bond-forming reactions. Isolation therefore connects fundamental carbene studies with synthetic chemistry.
Successful preparation depends on matching molecular design with handling conditions. Bulky substituents provide steric shielding, while electronic effects support the desired singlet or triplet state. Synthesis under an inert atmosphere limits unwanted reactions with the surroundings, and controlled temperature helps suppress decomposition or dimerization during preparation and recovery.
A practical workflow begins with synthesis and recovery of the target species, followed by handling under inert conditions and at a controlled temperature. The material must be protected from processes that could cause decomposition or dimerization during these stages. These steps are essential because persistence depends on both molecular design and experimental control.
Isolated carbenes give chemists direct platforms for examining carbon bonding, spin state, and reactivity in compounds that would otherwise be difficult to study. Stable NHCs extend that value into applications: they act as transition-metal ligands and as organocatalysts for bond-forming reactions. Carbene isolation therefore links fundamental structure studies to catalytic chemistry.