- Another silver complex of 1,3-dibenzylimidazol-2-ylidene: Solution and solid-state structures
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The reaction of 1,3-dibenzylimidazolium bromide (Bn2Im · HBr) with silver(I) oxide yields the dinuclear compound {(Bn2Im)AgBr}2 as determined with X-ray crystallography. The structure turned out to differ significantly fro
- Berding, Joris,Kooijman, Huub,Spek, Anthony L.,Bouwman, Elisabeth
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- MOF Encapsulating N-Heterocyclic Carbene-Ligated Copper Single-Atom Site Catalyst towards Efficient Methane Electrosynthesis
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The exploitation of highly efficient carbon dioxide reduction (CO2RR) electrocatalyst for methane (CH4) electrosynthesis has attracted great attention for the intermittent renewable electricity storage but remains challenging. Here,
- Chen, Mingzhao,Chen, Shenghua,Jiang, Wenjun,Li, Wen-Hao,Li, Yadong,Ou, Honghui,Sun, Xiaohui,Wang, Dingsheng,Wang, Liqiang,Yang, Jiarui,Zhu, Jiexin,Zhuang, Zechao
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supporting information
(2021/12/16)
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- DISSOLUTION OF CELLULOSE IN IONIC LIQUIDS
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The present invention includes a method for dissolving cellulose comprising dissolving cellulose in an ionic liquid and a co-solvent, wherein the ionic liquid is an imidazolium-based ionic liquid with, e.g., a halide or acetate as the anion.
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Paragraph 0153
(2019/08/08)
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- Synthesis and electrochemical evaluation of 2-substituted imidazolium salts
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Herein, we report the synthesis, electrochemical, and computational evaluation of six 2-substituted imidazolium bromides and six 2-substituted imidazolium triflates. All final compounds were obtained in 2 or fewer synthetic steps from inexpensive starting
- Hogan, David T.,Sutherland, Todd C.
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supporting information
(2018/03/22)
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- Small “Yaw” Angles, Large “Bite” Angles and an Electron-Rich Metal: Revealing a Stereoelectronic Synergy To Enhance Hydride-Transfer Activity
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Cyclometalated complexes are an important class of (pre)catalysts in many reactions including hydride transfer. The ring size of such complexes could therefore be a relevant aspect to consider while modulating their catalytic activity. However, any correl
- Semwal, Shrivats,Mukkatt, Indulekha,Thenarukandiyil, Ranjeesh,Choudhury, Joyanta
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supporting information
p. 13051 - 13057
(2017/09/26)
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- Unraveling the synthesis of homoleptic [Ag(N, N -diaryl-NHC)2]Y (Y = BF4, PF6) complexes by ball-milling
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A user-friendly and general mechanochemical method was developed to access rarely described NHC (N-heterocyclic carbene) silver(i) complexes featuring N,N-diarylimidazol(idin)ene ligands and non-coordinating tetrafluoroborate or hexafluorophosphate counter anions. Comparison with syntheses in solution clearly demonstrated the superiority of the ball-milling conditions.
- Beillard, Audrey,Bantreil, Xavier,Métro, Thomas-Xavier,Martinez, Jean,Lamaty, Frédéric
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supporting information
p. 17859 - 17866
(2016/11/18)
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- Acceptorless Dehydrogenative Oxidation of Secondary Alcohols Catalysed by Cp*IrIII–NHC Complexes
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A series of new IrIIIcomplexes with carbene ligands that contain a range of benzyl wingtip groups have been prepared and fully characterised by NMR spectroscopy, HRMS, elemental analysis and X-ray diffraction. All the complexes were active in the acceptorless dehydrogenation of alcohol substrates in 2,2,2-trifluoroethanol to give the corresponding carbonyl compounds. The most active complex bore an electron-rich carbene ligand; this complex was used to catalyse the highly efficient and chemoselective dehydrogenation of a wide range of secondary alcohols to their respective ketones, with turnover numbers up to 1660. Mechanistic studies suggested that the turnover of the dehydrogenation reaction is limited by the H2-formation step.
- Gülcemal, Süleyman,Gülcemal, Derya,Whitehead, George F. S.,Xiao, Jianliang
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supporting information
p. 10513 - 10522
(2016/07/21)
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- Iridium(I) N-Heterocyclic Carbene (NHC)/Phosphine Catalysts for Mild and Chemoselective Hydrogenation Processes
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The directed chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity. The directed, chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity.
- Kerr, William J.,Mudd, Richard J.,Brown, Jack A.
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supporting information
p. 4738 - 4742
(2016/04/05)
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- Expedient Mechanosynthesis of N,N-Dialkyl Imidazoliums and Silver(I)-Carbene Complexes in a Ball-Mill
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The absence of solvent, associated with intensive mechanical agitation, allowed the first mechanosynthesis of high-value silver(I)-carbene complexes and the corresponding N,N-dialkylimidazolium precursors. This procedure gave outstanding results in terms of yield and reaction time, when compared to solution-based conditions previously described in literature, and was generalized to unprecedented compounds. Silver(I)-carbene complexes could either be obtained from N,N-dialkylimidazolium salts or directly from imidazole and alkyl halides in a one-pot two-step procedure without isolating the imidazolium intermediate. Additionally, an efficient one-pot three-step sequence, including imidazole alkylation, silver metalation, and transmetalation is reported. You only hit twice! Solvent-free mechanochemical conditions enabled the rapid synthesis of high-value N,N-dialkyl-substituted NHC silver(I) complexes and the corresponding N,N-dialkylimidazolium precursors. Mechano-metalation and transmetalation are performed in a highly user- and eco-friendly approach. By using this strategy, up to three consecutive chemical steps, leading to organometallic complexes, could be performed in a ball-mill with high efficiency.
- Beillard, Audrey,Golliard, Ethan,Gillet, Valentin,Bantreil, Xavier,Métro, Thomas-Xavier,Martinez, Jean,Lamaty, Frédéric
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supporting information
p. 17614 - 17617
(2015/12/05)
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- Electrochemical flow-reactor for expedient synthesis of copper-N-heterocyclic carbene complexes
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An electrochemical flow-cell for highly efficient and selective generation of CuI-N-heterocyclic carbene complexes under neutral and ambient conditions is reported. The feasibility of the flow-cell is demonstrated through the electrochemical sy
- Chapman, Michael R.,Shafi, Yarseen M.,Kapur, Nikil,Nguyen, Bao N.,Willans, Charlotte E.
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supporting information
p. 1282 - 1284
(2015/02/19)
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- N-Heterocyclic carbene rhodium(i) complexes containing an axis of chirality: Dynamics and catalysis
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The novel rhodium(i) complexes [RhCl(NBD)(NHC)] [NBD = norbornadiene, NHC = 1-benzyl-3-R-imidazolin-2-ylidene; R = Me (3a), Bz (3b), Tr (3c), tBu (3d)], containing on one nitrogen the benzyl substituent and on the other increasing bulky alkyl substituents were prepared. All the complexes display restricted rotation around the metal-carbene bond and yield conformational enantiomers. The stereodynamics and racemization barriers about the Rh-carbene have been determined by means of NMR spectroscopy for 3a-c, whereas for the bulkiest 3d only the lower limit (91 kJ mol-1) could be calculated. Whilst the racemization barriers obtained by DFT calculations for 3a,b and 3d matched the experimental values, in the case of 3c the latter (62.3 kJ mol-1) was much smaller with respect to the calculated one (101.7 kJ mol-1). The lower experimental barrier has been attributed to a dissociative pathway that produces a solvated ionic pair in the transition state. The catalytic activity of the neutral rhodium(i) complexes 3a and 3d in the hydrosilylation with HSiMe2Ph of the terminal alkynes PhC≡CH, TolC≡CH, nBuC≡CH, Et3SiC≡CH, and (CPh2OH)C≡CH has been investigated, and compared with the amide-functionalized [RhCl(NBD){1-(2-NHBoc-ethyl)-3-Me-imidazolin-2-ylidene}] (4) and with [RhCl(NBD){1-butyl-3-Me-imidazolin-2-ylidene}] (5).
- Cassani, Maria Cristina,Brucka, Marta Anna,Femoni, Cristina,Mancinelli, Michele,Mazzanti, Andrea,Mazzoni, Rita,Solinas, Gavino
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supporting information
p. 1768 - 1779
(2014/05/06)
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- Gas-phase chemistry of benzyl cations in dissociation of N-Benzylammonium and N-benzyliminium ions studied by mass spectrometry
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In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Bronsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and parahalogen- substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase. American Society for Mass Spectrometry, 2012.
- Chai, Yunfeng,Wang, Lin,Sun, Hezhi,Guo, Cheng,Pan, Yuanjiang
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p. 823 - 833
(2012/09/07)
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- Convenient syntheses of bulky group containing imidazolium ionic liquids
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We report syntheses of bulky group containing imidazolium based ionic liquids. The bulky groups were introduced at N-1, C-2, and N-3 positions of the imidazole ring using convenient methodologies. Copyright
- Kumar, Neeraj,Jain, Rahul
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experimental part
p. 370 - 374
(2012/06/04)
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- Syntheses, crystal structures, reactivity, and photochemistry of gold(iii) bromides bearing N-heterocyclic carbenes
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Gold(i) complexes bearing N-heterocyclic carbenes (NHC) of the type (NHC)AuBr (3a/3b) [NHC = 1-methyl-3-benzylimidazol-2-ylidene (= MeBnIm), and 1,3-dibenzylimidazol-2-ylidene (= Bn2Im)] are prepared by transmetallation reactions of (tht)AuBr (tht = tetrahydrothiophene) and (NHC)AgBr (2a/2b). The homoleptic, ionic complexes [(NHC)2Au]Br (6a/6b) are synthesized by the reaction with free carbene. Successive oxidation of 3a/3b and 6a/6b with bromine gave the respective (NHC)AuBr3 (4a/4b) and [(NHC)2AuBr2]Br (7a/7b) in good overall yields as yellow powders. All complexes were characterized by NMR spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction. Reactions of the Au(iii) complexes towards anionic ligands like carboxylates, phenolates and thiophenolates were investigated and result in a complete or partial reduction to a Au(i) complex. Irradiation of the Au(iii) complexes with UV light yield the Au(i) congeners in a clean photo-reaction.
- Hirtenlehner, Christa,Krims, Charlotte,Hoelbling, Johanna,List, Manuela,Zabel, Manfred,Fleck, Michel,Berger, Raphael J. F.,Schoefberger, Wolfgang,Monkowius, Uwe
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scheme or table
p. 9899 - 9910
(2012/01/03)
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- TRIAZOLIUM AND IMIDAZOLIUM SALTS AND USES THEREOF
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The present disclosure relates to certain new and known triazolium and/or imidazolium salts and to their therapeutic use, for example in methods of treating or preventing an infection by a Plasmodium or Babesia parasite in a subject in need thereof. The triazolium and imidazolium salts are compounds of the Formula (I) or (II): wherein R1-R4, R1′-R3′, R8-R11, X, X′, X″, Y, Y′ and Y″ are as defined in the disclosure.
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Page/Page column 24
(2011/10/31)
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- Synthesis, cytotoxicity and antibacterial studies of p-methoxybenzyl- substituted and benzyl-substituted n-heterocyclic carbene-silver complexes
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p-Methoxybenzyl-substituted and benzyl-substituted Nheterocycllc carbene (NHC) [(3a-c) and (6a-c)] precursors were synthesised from, the reaction of 1H-imidazole (la), 4,5dichloro-1H-imidazole (1b), and 1H-benzimidazole (1c) with p-methoxybenzyl bromide (
- Patil, Siddappa,Claffey, James,Deally, Anthony,Hogan, Megan,Gleeson, Brendan,Mendez, Luis Miguel Menendez,Mueller-Bunz, Helge,Paradisi, Francesca,Tacke, Matthias
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experimental part
p. 1020 - 1031
(2010/06/20)
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- Anti-Plasmodium activity of imidazolium and triazolium salts
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We have previously reported that tetrazolium salts were both potent and specific inhibitors of Plasmodium replication, and that they appear to interact with a parasite component that is both essential and conserved. The use of tetrazolium salts in vivo is limited by the potential reduction of the tetrazolium ring to form an inactive, neutral acyclic formazan. To address this issue imidazolium and triazolium salts were synthesized and evaluated as Plasmodium inhibitors. Many of the imidazolium and triazolium salts were highly potent with active concentrations in the nanomolar range in Plasmodium falciparum cultures, and specific to Plasmodium with highly favorable therapeutic ratios. The results corroborate our hypothesis that an electron-deficient core is required so that the compound may thereby interact with a negatively charged moiety on the parasite merozoite; the side groups in the compound then form favorable interactions with adjacent parasite components and thereby determine both the potency and selectivity of the compound.
- Vlahakis, Jason Z.,Lazar, Carmen,Crandall, Ian E.,Szarek, Walter A.
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experimental part
p. 6184 - 6196
(2010/09/14)
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- 1,3-Dibenzylimidazolium salts: A paradigm of water and anion effect on the supramolecular H-bonds network
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Two crystals of 1,3-dibenzylimidazolium salts with chloride (crystal I) and hexafluorophosphate (crystal III) have been obtained by slow evaporation of a saturated aqueous solution for I and saturated chloroform solution for III. The two structures are de
- Leclercq, Lo?c,Simard, Michel,Schmitzer, Andreea R.
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experimental part
p. 101 - 107
(2009/05/08)
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- Dendrimer N-heterocyclic carbene complexes with rhodium(I) at the core
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Novel dendrimer N-heterocyclic carbene complexes with rhodium(I) located at the core were synthesized, and a positive dendrimer effect was found in the hydrosilylation of ketones catalyzed by them. The Royal Society of Chemistry 2005.
- Fujihara, Tetsuaki,Obora, Yasushi,Tokunaga, Makoto,Sato, Hiromichi,Tsuji, Yasushi
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p. 4526 - 4528
(2007/10/03)
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- An improved and convenient procedure for the synthesis of 1-substituted imidazoles
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1-Protected imidazoles, such as 1-acetyl- and 1-benzoylimidazoles, react with various halides, such as benzyl, allyl, α-keto, and alkyl halides, to give 1-protected-3-substituted imidazolium salts in high yields. The resultant imidazolium salts are easily deprotected by treatment with water or alcohols to give the corresponding 1-substituted imidazoles in excellent yields. In this reaction the yields of 1-substituted imidazoles vary with the kinds of halides used and/or with the protecting groups, and the yields increase in the following order: benzyl halides≥allyl halides~α-keto halides>alkyl halides, and acetyl≥benzoyl>ethoxycarbonyl>diethoxymethyl>trimethylsilyl>tosyl.
- Kamijo,Yamamoto,Harada,Iizuka
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p. 1213 - 1221
(2007/10/02)
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