382147-43-5

Upstream product

• 141556-42-5 [1,3-bis(2,4,6-trimethylphenyl)imidazol]-2-ylidene 
• 1010101-96-8 1,3-bis(2,4,6-trimethylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene 
• 141556-45-8 1,3-bis(mesityl)imidazolium chloride 
• 1354689-39-6 1,3-dimesitylimidazol-2-ylidene-NNO 
• 1187968-87-1 GaCl₂H(IMes) 

Relevant academic research and scientific papers

Studies of the reactivity of N-heterocyclic carbenes with halogen and halide sources

The reactivity of the N-heterocyclic carbene (NHC) 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, IMes, with a series of halide sources, including 1,1,1,2,2,2-hexachloroethane, 1,2-dibromoethane and dibromine, has been assessed. These result in the formation of the imidazolium species 1,3-bis(2,4,6-trimethylphenyl)-2-chloroimidazolium chloride, [IMesCl][Cl], 1,3-bis(2,4,6-trimethylphenyl)imidazolium bromide, [IMesH][Br] and 1,3-bis(2,4,6-trimethylphenyl)-2-bromoimidazolium bromide, [IMesBr][Br]. Treatment of IMes with 2.0 equiv. of carbon tetrabromide, CBr4, in tetrahydrofuran or benzene yields the new NHC 1,3-bis(2,4,6-(trimethylphenyl)-4,5-dibromoimidazol-2-ylidene, IMesBr2. IMesBr2 is indefinitely stable in air and has been characterised by XRD. The molecular and supramolecular structures of compounds [IMesBr][Br]·3MeCN, [IMesH][Br], [IMesCl][Cl]·MeCN and [IMesCl][AlCl4], the latter formed from the addition of aluminium trichloride to [IMesCl][Cl], are discussed.

Synthesis and characterisation of the first carbene-thallium complexes: Molecular structure of[TlCl3{CN(Mes)C2H2N(Mes)}], Mes = C6H2Me3-2,4,6

The reaction of the stable carbenes,:CN(Mes)C2R2N(Mes), R = H (IMes) or Br (IMesBr), with TlX3, X = Cl or Br, Mes = mesityl, yields the complexes, [TlX3{CN(Mes)- C2R2N(Mes)}], one of which,

Triazenyl Radicals Stabilized by N-Heterocyclic Carbenes

Notwithstanding the notable progress in the synthesis of N-heterocyclic carbene-stabilized radicals, aminyl radicals, supported by NHCs or otherwise, have been scarcely studied due to synthetic challenges. Triazenyl radical is a particular form of aminyl radical that contains three adjacent nitrogen atoms, and offers intriguing possibilities for unique reactivity and physical properties stemming from expected delocalization of the spin density over the NNN moiety and its conjugated substituents. Here, we report the synthesis and full characterization of the first NHC-stabilized triazenyl radicals, obtained by one-electron reduction of the corresponding triazenyl cations with potassium metal. These radicals reversibly oxidize back to the cations upon treatment with transition metal sources or electrophiles, and abstract H atom from xanthene to form a new N - H bond at the center nitrogen atom. Potential application of the redox couple between triazenyl cation and triazenyl radical was demonstrated as cathode active materials in lithium ion batteries.

Direct Azidation of Phenols

Direct azidation of phenols was developed. By treating chloroimidazolinium chloride 1b and sodium azide with phenol in the presence of a secondary amine in methoxyethanol, ortho-azidation of phenol was achieved.

Neutral Nickel(II) Complexes Bearing Aryloxide Imidazolin-2-imine Ligands for Efficient Copolymerization of Norbornene and Polar Monomers

A series of novel aryloxide imidazolin-2-imine bidentate neutral Ni(II) complexes with different substituents on the imidazolin-2-imine ligand were synthesized and characterized. The complex Ni2 bearing a 2,6-diisopropylphenyl substituent adopted an almost square planar geometry, while the bulkier 2,6-bis(diphenylmethyl)-4-methylphenyl substituent ligated complex Ni3 was obtained in an allyl adduct base-free η3 coordination mode. In the presence of B(C6F5)3, these Ni(II) complexes exhibited remarkably high activity (up to 2.7 × 107 g of PNB (mol of Ni)-1 h-1) and particularly good thermal stability toward the addition polymerization of norbornene. Most importantly, these catalysts were able to promote the direct copolymerization of norbornene with various polar monomers with high activity (～105 g (mol of Ni)-1 h-1), reasonable comonomer incorporation (0.14-3.08%), and high copolymer molecular weight (Mn up to 2.0 × 105). The strategy of installing a strongly electron donating imidazolin-2-imine ligand on the nickel complex demonstrates a great advantage for the copolymerization of an olefin with polar monomers.

Adducts of nitrous oxide and N-heterocyclic carbenes: Syntheses, structures, and reactivity

N-Heterocyclic carbenes (NHCs) react at ambient conditions with nitrous oxide to give covalent adducts. In the crystal, all compounds show a bent N 2O group connected via the N-atom to the former carbene carbon atom. Most adducts are stable at room temperature, but heating induces decomposition into the corresponding ureas. Kinetic experiments show that the thermal stability of the NHC-N2O adducts depends on steric as well as electronic effects. The coordination of N2O to NHCs weakens the N-N bond substantially, and facile N-N bond rupture was observed in reactions with acid or acetyl chloride. On the other hand, reaction with tritylium tetrafluoroborate resulted in a covalent modification of the terminal O-atom, and cleavage of the C-N2O bond was observed in a reaction with thionyl chloride. The coordination chemistry of IMes-N2O (IMes = 1,3-dimesitylimidazol-2-ylidene) was explored in reactions with the complexes CuOTf, Fe(OTf)2, PhSnCl3, CuCl2, and Zn(C 6F5)2. Structural analyses show that IMes-N2O is able to act as a N-donor, as an O-donor, or as a chelating N,O-donor. The different coordination modes go along with pronounced electronic changes as evidenced by a bond length analysis.

Low valent and hydride complexes of NHC coordinated gallium and indium

The reactions of the N-heterocyclic carbene 1,3-dimesitylimidazol-2-ylidene (IMes) with Ga[GaCl4], "GaI", InCl2 and GaBr3 have been examined. All reactions using a low valent gallium or indium starting material led to species of the form [{MX2(IMes)} 2], where M = Ga, X = Cl (1), I (2); M = In, X = Cl (3), with disproportionation and loss of gallium metal in the case of 2. Reaction of IMes with gallium tribromide yields the air and moisture stable complex [GaBr 3(IMes)] (4), which has been used as a precursor to the mixed bromohydrides [GaBrH2(IMes)] (5) and [GaBr2H(IMes)] (6) by (i) ligand redistribution with [GaH3(IMes)], (ii) hydride-bromide exchange with triethylsilane, and (iii) alkylation with nbutyllithium followed by β-hydride elimination (6 only). Attempts to prepare 1, or monovalent analogues such as [{GaCl(IMes)}n], by thermally induced reductive elimination of dihydrogen from the chlorohydride congeners of 5 and 6 resulted in isolation of the known compounds [IMesCl][Cl] (IMesCl = 1,3-dimesityl-2-chloroimidazolium), and/or 1,3-dimesityl-2-dihydroimidazole, and gallium metal. Preliminary photochemical NMR spectroscopy and catalytic studies of 5 and 6 aimed at reductive dehydrogenation under milder conditions are reported. Compounds 1 and 4 have been characterised by single crystal X-ray structure determination.

The synthesis, characterisation and electronic structure of N-heterocyclic carbene adducts of PI cations

Two different syntheses of N-heterocyclic carbene complexes of P I cations are presented; the structural features of these phosphamethine cyanine salts, in conjunction with the results of computational investigations, provide insight into the n