共查询到20条相似文献,搜索用时 15 毫秒
1.
《Journal of organometallic chemistry》2005,690(24-25):6068-6078
Gradient-corrected (BP86) density-functional calculations were used to study the chemical bond between transition-metal complexes and N- and P-heterocyclic carbenes EHC (EHC = imidazolin-2-ylidene; 1,3-dimethylimidazolin-2-ylidene; 1,3-dihydro-1,3-diphosphol-2-ylidene; 1,3-dimethyl-1,3-diphosphol-2-ylidene). Forty two complexes of the type [M] ← EHC, [M] = CuCl, AgCl, AuCl, BeCl+, Cu+, Ag+, Au+, have been studied. Both electrostatic contributions as well as π-back-donation are of special importance for the [M] ← EHC bond. The metal–ligand bond strengths are comparable for NHC and PHC complexes. Whereas the former undergo stronger electrostatic interactions, the latter show a higher degree of π-bonding. When considering NHC and PHC as ligands for transition-metal-based catalysts, the results of the present study suggest that PHC both compete with NHC – in terms of metal-to-ligand bond strength – as well as complement NHC – in terms of the nature of the metal–ligand bond. 相似文献
2.
Generalization of the Copper to Late‐Transition‐Metal Transmetallation to Carbenes beyond N‐Heterocyclic Carbenes
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Dr. Yannick D. Bidal Orlando Santoro Dr. Mohand Melaimi Dr. David B. Cordes Prof. Alexandra M. Z. Slawin Prof. Guy Bertrand Dr. Catherine S. J. Cazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9404-9409
Carbene transition‐metal complexes have become a prevalent family of catalysts enabling numerous organic transformations. Their facile synthetic access is a matter of great importance. To this end, the CuI‐NHC transfer methodology has emerged as a powerful alternative presenting attractive advantages over other methods. Herein, we report the remarkable ability of copper to transfer not only NHCs but also other types of carbenes such as abnormal NHCs (aNHCs), cyclic (alkyl)(amino)carbenes (CAACs), and mesoionic carbenes (MICs) to various transition metal precursors. 相似文献
3.
Dr. Mathias Paul Eric Detmar Dr. Maria Schlangen Dr. Martin Breugst Dr. Jörg-Martin Neudörfl Prof. Dr. Dr. Helmut Schwarz Prof. Dr. Albrecht Berkessel Prof. Dr. Mathias Schäfer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(10):2511-2518
N-Heterocyclic carbenes (NHCs, :C ) can interact with azolium salts ( C−H+ ) by either forming a hydrogen-bonded aggregate ( CHC+ ) or a covalent C−C bond ( CCH+ ). In this study, the intramolecular NHC–azolium salt interactions of aromatic imidazolin-2-ylidenes and saturated imidazolidin-2-ylidenes have been investigated in the gas phase by traveling wave ion mobility mass spectrometry (TW IMS) and DFT calculations. The TW IMS experiments provided evidence for the formation of these important intermediates in the gas phase, and they identified the predominant aggregation mode (hydrogen bond vs. covalent C−C) as a function of the nature of the interacting carbene–azolium pairs. 相似文献
4.
Junbeom Park Jaelim Kim Gu Yoon Jeong Prof. Dr. Youngsuk Kim Prof. Dr. Eunsung Lee 《Angewandte Chemie (International ed. in English)》2023,62(51):e202314978
N-heterocyclic carbenes (NHCs) have garnered much attention due to their unique properties, such as strong σ-donating and π-accepting abilities, as well as their transition-metal-like reactivity toward small molecules. In 2015, we discovered that NHCs can react with nitric oxide (NO) gas to form radical adducts that resemble transition metal nitrosyl complexes. To elucidate the analogy between NHC and transition metal NO adducts, here we have undertaken a systematic investigation of the electron- and proton-transfer chemistry of [NHC−NO]⋅ (N-heterocyclic carbene nitric oxide radical) compounds. We have accessed a suite of compounds, comprised of [NHC−NO]+, [NHC−NO]−, [NHC−NOH]0, and [NHC−NHOH]+ species. In particular, [NHC−NO]− was isolated as potassium and lithium ion adducts. Most interestingly, a monomeric potassium [NHC−NO]− compound was isolated with the assistance of 18-crown-6, which is the first instance of a monomeric alkali N-oxyl compound to the best of our knowledge. Our results demonstrate that [NHC−NO]⋅ exhibits redox behavior broadly similar to metal nitrosyl complexes, which opens up more possibilities for utilizing NHCs to build on the known reactivity of metal complexes. 相似文献
5.
Unusual NHC–Iridium(I) Complexes and Their Use in the Intramolecular Hydroamination of Unactivated Aminoalkenes
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Gellért Sipos Arnold Ou Prof. Brian W. Skelton Dr. Laura Falivene Prof. Luigi Cavallo Prof. Reto Dorta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(20):6939-6946
N‐heterocyclic carbene (NHC) ligands with naphthyl side chains were employed for the synthesis of unsaturated, yet isolable [(NHC)Ir(cod)]+ (cod=1,5‐cyclooctadiene) complexes. These compounds are stabilised by an interaction of the aromatic wingtip that leads to a sideways tilt of the NHC?Ir bond. Detailed studies show how the tilting of such N‐heterocyclic carbenes affects the electronic shielding properties of the carbene carbon atom and how this is reflected by significant upfield shifts in the 13C NMR signals. When employed in the intramolecular hydroamination, these [(NHC)Ir(cod)]+ species show very high catalytic activity under mild reaction conditions. An enantiopure version of the catalyst system produces pyrrolidines with excellent enantioselectivities. 相似文献
6.
An efficient phospho-aldol reaction of aldehydes catalyzed by N-heterocyclic carbenes (NHCs) has been developed. With 10 mol% stable NHC 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, various aldehydes reacted with dialkylphosphites smoothly to provide a-hydroxy phosphonates in 59%--99% yield. In this process, NHC was assumed to function as a carbon-centered bronsted base. 相似文献
7.
The common use of NHC complexes in transition‐metal mediated C–C coupling and metathesis reactions in recent decades has established N‐heterocyclic carbenes as a new class of ligand for catalysis. The field of asymmetric catalysis with complexes bearing NHC‐containing chiral ligands is dominated by mixed carbene/oxazoline or carbene/phosphane chelating ligands. In contrast, applications of complexes with chiral, chelating bis(NHC) ligands are rare. In the present work new chiral iridium(I) bis(NHC) complexes and their application in the asymmetric transfer hydrogenation of ketones are described. A series of chiral bis(azolium) salts have been prepared following a synthetic pathway, starting from L ‐valinol and the modular buildup allows the structural variation of the ligand precursors. The iridium complexes were formed via a one‐pot transmetallation procedure. The prepared complexes were applied as catalysts in the asymmetric transfer hydrogenation of various prochiral ketones, affording the corresponding chiral alcohols in high yields and moderate to good enantioselectivities of up to 68%. The enantioselectivities of the catalysts were strongly affected by the various, terminal N‐substituents of the chelating bis(NHC) ligands. The results presented in this work indicate the potential of bis‐carbenes as stereodirecting ligands for asymmetric catalysis and are offering a base for further developments. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
8.
Dr. Yan Li Dr. Yuk-Chi Chan Bi-Xiang Leong Dr. Yongxin Li Dr. Emma Richards Indu Purushothaman Dr. Susmita De Dr. Pattiyil Parameswaran Dr. Cheuk-Wai So 《Angewandte Chemie (International ed. in English)》2017,56(26):7573-7578
The trapping of a silicon(I) radical with N-heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6-iPr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− ( 1 ), which features a cationic cAAC–silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC–iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− ( 2 ) comprising the first NHC–parent-silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1-F-2-IMe-C6H4]+I− ( 3 ). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1 . Compounds 1 – 3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X-ray crystallography. 相似文献
9.
Youngsuk Kim Prof. Kimoon Kim Prof. Eunsung Lee 《Angewandte Chemie (International ed. in English)》2018,57(1):262-265
N‐heterocyclic carbene (NHC) nitric oxide (NHCNO) radicals, which can be regarded as iminoxyl radicals stabilized by NHCs, were found to react with a series of silyl and alkyl triflates to generate the corresponding oxime ether radical cations. The structures of the resulting oxime ether radical cations were determined by X‐ray crystallography, along with EPR and computational analysis. In contrast, lutidinium triflate produced a 1:1 mixture of [NHCNO+][OTf?] and [NHCNHOH+][OTf?] upon the reaction with NHCNO. This study adds an important example of stable singlet carbenes for stabilizing main‐group radicals because of their π‐conjugating effect, the synthesis and structures of which have not been reported previously. 相似文献
10.
Dr. Felix Riedlberger Dr. Stefano Todisco Prof. Dr. Piero Mastrorilli Prof. Dr. Alexey Y. Timoshkin Dr. Michael Seidl Prof. Dr. Manfred Scheer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16251-16255
The first adducts of NHCs (=N-heterocyclic carbenes) with aromatic polyphosphorus complexes are reported. The reactions of [Cp*Fe(η5-P5)] ( 1 ) (Cp*=pentamethyl-cyclopentadienyl) with IMe (=1,3,4,5-tetramethylimidazolin-2-ylidene), IMes (=1,3-bis(2,4,6-trimethylphenyl)-imidazolin-2-ylidene) and IDipp (=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene) led to the corresponding neutral adducts which can be isolated in the solid state. However, in solution, they quickly undergo a dissociative equilibrium between the adduct and 1 including the corresponding NHC. The equilibrium is influenced by the bulkiness of the NHC. [Cp′′Ta(CO)2(η4-P4)] (Cp′′=1,3-di-tert-butylcyclopentadienyl) reacts with IMe under P atom abstraction to give an unprecedented cyclo-P3-containing anionic tantalum complex. DFT calculations shed light onto the energetics of the reaction pathways. 相似文献
11.
Cyclic (Alkyl)(Amino)Carbene Complexes of Rhodium and Nickel and Their Steric and Electronic Parameters
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Ursula S. D. Paul Carolin Sieck Dr. Martin Haehnel Kai Hammond Prof. Dr. Todd B. Marder Prof. Dr. Udo Radius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):11005-11014
N‐heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) are of great interest, as their electronic and steric properties provide a unique class of ligands and organocatalysts. Herein, substitution reactions involving novel carbonyl complexes of rhodium and nickel were studied to provide a deeper understanding of the fundamental electronic factors characterizing CAACmethyl, which were compared with the large array of data available for NHC and sterically more demanding CAAC ligands. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7681-7686
The trapping of a silicon(I) radical with N‐heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6‐i Pr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− ( 1 ), which features a cationic cAAC–silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC–iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− ( 2 ) comprising the first NHC–parent‐silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1‐F‐2‐IMe‐C6H4]+I− ( 3 ). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1 . Compounds 1 – 3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X‐ray crystallography. 相似文献
13.
Dr. Dominik Munz Dr. Jiaxiang Chu Dr. Mohand Melaimi Prof. Dr. Guy Bertrand 《Angewandte Chemie (International ed. in English)》2016,55(41):12886-12890
The synthesis of N‐heterocyclic carbene (NHC)–cyclic (alkyl)(amino) carbene (CAAC) heterodimers is presented. As the free carbenes do not react together in solution, the synthetic approach involves the addition of a free NHC to a cyclic iminium salt, which results in the formation of the protonated heterodimer. Subsequent deprotonation leads to the isolation of the corresponding mixed Wanzlick dimers. One‐ and two‐electron oxidations of these triazaolefins result in the formation of stable cationic radicals and bis(cations), respectively, which have been isolated and fully characterized. Cyclic voltammetry, UV/Vis spectroscopy, spin density, and DFT calculations suggest that these heterodimers feature complementary electronic properties to tetrathiafulvalenes (TTFs). 相似文献
14.
Siddappa Patil Anthony Deally Frauke Hackenberg Leonard Kaps Helge Müller‐Bunz Rainer Schobert Matthias Tacke 《Helvetica chimica acta》2011,94(9):1551-1562
N‐Heterocyclic carbene (NHC) complexes bromo(1,3‐dibenzyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene)silver(I) ( 2a ), bromo[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene]silver(I) ( 2b ), and bromo[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐benzimidazol‐2‐ylidene]silver(I) ( 2c ) were prepared by the reaction of 1,3‐dibenzyl‐1H‐imidazol‐3‐ium bromide ( 1a ), 3‐(4‐cyanobenzyl)‐1‐methyl‐1H‐imidazol‐3‐ium bromide ( 1b ), and 3‐(4‐cyanobenzyl)‐1‐methyl‐1H‐benzimidazol‐3‐ium bromide ( 1c ), respectively, with silver(I) oxide. NHC Complexes chloro(1,3‐dibenzyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene)gold(I) ( 3a ), chloro[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene]gold(I) ( 3b ), and chloro[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐benzimidazol‐2‐ylidene]gold(I) ( 3c ) were prepared via transmetallation of corresponding (bromo)(NHC)silver(I) complexes with chloro(dimethylsulfido)gold(I). The complex 3a was characterized in two polymorphic forms by single‐crystal X‐ray diffraction showing two rotamers in the solid state. The cytotoxicities of all three bromo(NHC)silver(I) complexes and three (chloro)(NHC)gold(I) complexes were investigated through 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bormide (MTT)‐based preliminary in vitro testing on the Caki‐1 cell line in order to determine their IC50 values. (Bromo)(NHC)silver(I) complexes 2a – 2c and (chloro)(NHC)gold(I) complexes 3a – 3c were found to have IC50 values of 27±2, 28±2, 34±6, 10±1, 12±5, and 12±3 μM , respectively, on the Caki‐1 cell line. 相似文献
15.
Rosenani A. Haque Abbas Washeel Salman Teoh Siang Guan Hassan Hadi Abdallah 《Journal of organometallic chemistry》2011,696(22):3507-3512
Mononuclear mercury complexes (1, 2, and 3) bearing bis-N-heterocyclic carbene (NHC) ligands of the form [(NHC)2-μ-Hg]+2 have been prepared and structurally characterised. The complexes were derived from three bis-imidazolium salts as precursors to NHC; either 1,3-bis(N-methylimidazolium-1-ylmethyl)benzene bis(hexafluorophosphate) (I·2PF6), 1,3-bis(N-butylimidazolium-1-ylmethyl)benzene bis(hexafluorophosphate) (II·2PF6) or 3,5-bis(N-butylimidazolium-1-ylmethyl)toluene bis(hexafluorophosphate) (III·2PF6) treated with mercury(II) acetate. Interestingly X-ray crystal structure analysis revealed a close interaction between the Hg metal centre with one carbon atom of the aryl linker in addition to coordination with two NHCs. 相似文献
16.
《Angewandte Chemie (International ed. in English)》2017,56(34):10209-10213
The reactivity of N‐heterocyclic carbenes (NHCs) and cyclic alkyl amino carbenes (cAACs) with arylboronate esters is reported. The reaction with NHCs leads to the reversible formation of thermally stable Lewis acid/base adducts Ar‐B(OR)2⋅NHC ( Add1 – Add6 ). Addition of cAACMe to the catecholboronate esters 4‐R‐C6H4‐Bcat (R=Me, OMe) also afforded the adducts 4‐R‐C6H4Bcat⋅cAACMe ( Add7 , R=Me and Add8 , R=OMe), which react further at room temperature to give the cAACMe ring‐expanded products RER1 and RER2 . The boronate esters Ar‐B(OR)2 of pinacol, neopentylglycol, and ethyleneglycol react with cAAC at RT via reversible B−C oxidative addition to the carbene carbon atom to afford cAACMe(B{OR}2)(Ar) ( BCA1 – BCA6 ). NMR studies of cAACMe(Bneop)(4‐Me‐C6H4) ( BCA4 ) demonstrate the reversible nature of this oxidative addition process. 相似文献
17.
Dr. Jianguo Wu Dr. Ainara Nova Dr. David Balcells Dr. Gary W. Brudvig Dr. Wei Dai Louise M. Guard Dr. Nilay Hazari Dr. Po‐Heng Lin Dr. Ravi Pokhrel Dr. Michael K. Takase 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5327-5337
The reaction of (μ‐Cl)2Ni2(NHC)2 (NHC=1,3‐bis(2,6‐diisopropylphenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene (IPr) or 1,3‐bis(2,6‐diisopropylphenyl)imidazolidin‐2‐ylidene (SIPr)) with either one equivalent of sodium cyclopentadienyl (NaCp) or lithium indenyl (LiInd) results in the formation of diamagnetic NHC supported NiI dimers of the form (μ‐Cp)(μ‐Cl)Ni2(NHC)2 (NHC=IPr ( 1 a ) or SIPr ( 1 b ); Cp=C5H5) or (μ‐Ind)(μ‐Cl)Ni2(NHC)2 (NHC=IPr ( 2 a ) or SIPr ( 2 b ); Ind=C7H9), which contain bridging Cp and indenyl ligands. The corresponding reaction between two equivalents of NaCp or LiInd and (μ‐Cl)2Ni2(NHC)2 (NHC=IPr or SIPr) generates unusual 17 valence electron NiI monomers of the form (η5‐Cp)Ni(NHC) (NHC=IPr ( 3 a ) or SIPr ( 3 b )) or (η5‐Ind)Ni(NHC) (NHC=IPr ( 4 a ) or SIPr ( 4 b )), which have nonlinear geometries. A combination of DFT calculations and NBO analysis suggests that the NiI monomers are more strongly stabilized by the Cp ligand than by the indenyl ligand, which is consistent with experimental results. These calculations also show that the monomers have a lone unpaired‐single‐electron in their valence shell, which is the reason for the nonlinear structures. At room temperature the Cp bridged dimer (μ‐Cp)(μ‐Cl)Ni2(NHC)2 undergoes homolytic cleavage of the Ni?Ni bond and is in equilibrium with (η5‐Cp)Ni(NHC) and (μ‐Cl)2Ni2(NHC)2. There is no evidence that this equilibrium occurs for (μ‐Ind)(μ‐Cl)Ni2(NHC)2. DFT calculations suggest that a thermally accessible triplet state facilitates the homolytic dissociation of the Cp bridged dimers, whereas for bridging indenyl species this excited triplet state is significantly higher in energy. In stoichiometric reactions, the NiI monomers (η5‐Cp)Ni(NHC) or (η5‐Ind)Ni(NHC) undergo both oxidative and reductive processes with mild reagents. Furthermore, they are rare examples of active NiI precatalysts for the Suzuki–Miyaura reaction. Complexes 1 a , 2 b , 3 a , 4 a and 4 b have been characterized by X‐ray crystallography. 相似文献
18.
A series of p-tert-butylcalix[4]arene 1,3-diimidazolium salts were successfully prepared by the alkylation of p-tert-butylcalix[4]arene with dibromoalkanes, and sequential substitution reaction with 1-alkylimidazole. Furthermore, coordination reactions of p-tert-butylcalix[4]arene 1,3-diimidazolium salts with silver oxide and mercury acetate gave novel Ag and Hg complexes of bis(N-heterocyclic carbenes) on p-tert-butylcalix[4]arene platform. The single-crystal structures of four p-tert-butylcalix[4]arene 1,3-diimidazolium salts and three metal complexes were successfully determined by X-ray diffraction. An Ag–Ag argentophilic interaction (Ag–Ag bond length is 3.1599(6) Å) is formed between the two Ag–NHC complexes and a dimetallic coordination mode exists in Hg–NHC complexes. 相似文献
19.
Alexander Bechtoldt Hans‐Wolfram Lerner Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(6):448-451
The aurophilicity exhibited by AuI complexes depends strongly on the nature of the supporting ligands present and the length of the Au–element (Au—E) bond may be used as a measure of the donor–acceptor properties of the coordinated ligands. A binuclear iron–gold complex, [1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene‐2κC2]dicarbonyl‐1κ2C‐(1η5‐cyclopentadienyl)gold(I)iron(II)(Au—Fe) benzene trisolvate, [AuFe(C5H5)(C27H36N2)(CO)2]·3C6H6, was prepared by reaction of K[CpFe(CO)2] (Cp is cyclopentadienyl) with (NHC)AuCl [NHC = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]. In addition to the binuclear complex, the asymmetric unit contains three benzene solvent molecules. This is the first example of a two‐coordinated Au atom bonded to an Fe and a C atom of an N‐heterocyclic carbene. 相似文献
20.
Jenni Frosch Marvin Koneczny Dr. Thomas Bannenberg Prof. Dr. Matthias Tamm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(13):4349-4363
The lithium complexes [(WCA-NHC)Li(toluene)] of anionic N-heterocyclic carbenes with a weakly coordinating anionic borate moiety (WCA-NHC) reacted with iodine, bromine, or CCl4 to afford the zwitterionic 2-halogenoimidazolium borates (WCA-NHC)X (X=I, Br, Cl; WCA=B(C6F5)3, B{3,5-C6H3(CF3)2}3; NHC=IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, or NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene). The iodine derivative (WCA-IDipp)I (WCA=B(C6F5)3) formed several complexes of the type (WCA-IDipp)I ⋅ L (L=C6H5Cl, C6H5Me, CH3CN, THF, ONMe3), revealing its ability to act as an efficient halogen bond donor, which was also exploited for the preparation of hypervalent bis(carbene)iodine(I) complexes of the type [(WCA-IDipp)I(NHC)] and [PPh4][(WCA-IDipp)I(WCA-NHC)] (NHC=IDipp, IMes). The corresponding bromine complex [PPh4][(WCA-IDipp)2Br] was isolated as a rare example of a hypervalent (10-Br-2) system. DFT calculations reveal that London dispersion contributes significantly to the stability of the bis(carbene)halogen(I) complexes, and the bonding was further analyzed by quantum theory of atoms in molecules (QTAIM) analysis. 相似文献