Microwave‐Assisted Synthesis of (N‐Heterocyclic carbene)MCl Complexes of Group 11 Metals

Landers, Brant; Navarro, Oscar

doi:10.1002/ejic.201200248

Cited by 48 publications

(31 citation statements)

References 18 publications

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“…Conventional heating conditions used for the preparation of 2 CuCl and 3 CuCl did not result in full conversion of 4 HCl even after 24 h in refluxing solvents. However, under microwave irradiation19 for 2.5 h at 80 °C in acetonitrile, the copper complex 4 CuCl , bearing a 1,2,3‐triazol‐5‐ylidene IV , was cleanly obtained. After recrystallization from dichloromethane/diethyl ether, 4 CuCl was isolated in a 95% yield.…”

Section: Resultsmentioning

confidence: 99%

Copper(I) Complexes Bearing Carbenes Beyond Classical N‐Heterocyclic Carbenes: Synthesis and Catalytic Activity in “Click Chemistry”

et al. 2015

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Thes ynthesis andc haracterization of abnormal N-heterocyclic carbene,c yclic (alkyl)(amino)carbene,a nd mesoionic carbene copper(I) complexesa re reported.T hese organometallic species are obtained via aversatile and inexpensive synthetic pathwayu sing readily available reactants,n amely copper oxide andi miniums alts.T he catalytic activity of this series of complexes was evaluated in the [3+ +2] cycloaddition of alkynes with azides (CuAAC). Outstanding catalytic properties were observed for the abnormal NHC-a nd triazolylidenebased copper(I) complexes.

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Section: Resultsmentioning

confidence: 99%

Copper(I) Complexes Bearing Carbenes Beyond Classical N‐Heterocyclic Carbenes: Synthesis and Catalytic Activity in “Click Chemistry”

et al. 2015

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“…(JohnPhos)AuCl and ( t -BuXPhos)AuCl, were prepared by displacement of dimethyl sulfide from Me 2 SAuCl by JohnPhos or t -BuXPhos [23–24]. The (NHC)AuCl (NHC = SIMes, IMes, SIPr, IPr) [19,25] precursors as well as arylgold compounds 1 – 3 [14] were prepared following literature procedures. The arylboronic acids, alkynes, phenols, and Cs 2 CO 3 (powder) were obtained from Aldrich and used as received.…”

Section: Methodsmentioning

confidence: 99%

Acid, silver, and solvent-free gold-catalyzed hydrophenoxylation of internal alkynes

Richard¹,

Fraccica²,

Garcia³

et al. 2013

Beilstein J. Org. Chem.

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SummaryA range of arylgold compounds have been synthesized and investigated as single-component catalysts for the hydrophenoxylation of unactivated internal alkynes. Both carbene and phosphine-ligated compounds were screened as part of this work, and the most efficient catalysts contained either JohnPhos or IPr/SIPr. Phenols bearing either electron-withdrawing or electron-donating groups were efficiently added using these catalysts. No silver salts, acids, or solvents were needed for the catalysis, and either microwave or conventional heating afforded moderate to excellent yields of the vinyl ethers.

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“…of Cu(I) oxide were heated in THF at 110 C in a sealed tube, under microwave irradiation. After 1 h, the starting materials were recovered [91]. Thirdly, Ag(I)eNHC complexes being efficient at transmetalating their carbene ligand(s) to copper(I), 2c was placed in presence of CuI, in dichloromethane, at room temperature for 18 h [40,92].…”

Section: Synthesis Of the Copper(i) Complexesmentioning

confidence: 99%

Silver(I) and copper(I) complexes with bis-NHC ligands: Dinuclear complexes, cubanes and coordination polymers

Charra

Frémont

Breuil

et al. 2015

Journal of Organometallic Chemistry

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a b s t r a c tSilver(I) and copper(I) complexes containing neutral bis(N-heterocyclic carbene) (NHC) ligands and coordinated or non-coordinated chloride, bromide, iodide, or tetrafluoroborate anions, were synthesised. The nature of the anions impacts deeply the structural features of the complexes in the solid-state and neutral cubane-, neutral coordination polymer-, or dicationic bridged-type architectures have been characterised. The structures of (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)disilver(I) dichloride (2a), bis(m-1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene-k-C)tetra-m 3 -bromotetrasilver(I) (2b), bis(1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)disilver(I) tetrafluoroborate (2d) in 2d$CH 2 Cl 2 , (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)dicopper(I) dichloride (3a) and (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene) dicopper(I) dibromide (3b) were established by X-ray diffraction. IntroductionSince the first stable free N-heterocyclic carbene (NHC) was isolated by Arduengo in 1991 [1], this class of ligands has found numerous applications in organometallic chemistry in particular for the preparation of new metal-based catalysts [2e9]. The first NHC silver(I) complex was prepared by Arduengo et al. by reaction between a free carbene and silver(I) triflate [10]. Today, the reaction of imidazol(in)ium salts with a variety of silver(I) precursors such as Ag 2 O [11], Ag(OAc) [12,13], Ag 2 CO 3 [14] or AgCl [15], with K 2 CO 3 or Na 2 CO 3 as external base, allows for the formation of Ag(I)eNHC complexes in high yields. Ag(I)eNHC complexes are stable towards air and moisture. The reaction of Ag 2 O with halide imidazol(in)ium salts, first described in 1998 by Lin, is particularly efficient to synthesise halide Ag(I)eNHC complexes under mild conditions, without having to handle free NHCs [11]. The second product formed following Lin's protocol being water, non-distilled solvents can be employed, which renders this approach very convenient and popular [11]. Ag(I)eNHC complexes are potent catalysts for e.g. the cycloaddition of CO 2 to terminal epoxides [16] and CeN coupling reactions [17]. During pharmacological studies, they proved to release in vivo slowly and steadily free silver cations acting as tumour cell killers or suppressants of infections [18e21]. Ag(I)e NHCs are mostly employed as transmetalating agents to access late transition metal NHC complexes, without the need to handle unwieldy free carbenes. They are indeed known to transmetalate efficiently their NHC ligand(s) to Cu [22], Ni [23,24] Pd [23,25], Pt [25] and Au [26,27] precursors. The coordination geometry around the Ag(I) centre tends to be linear. When the associated anion (X À ) is a halide, the formation of polynuclear complexes or clusters with XeAgeX bridge(s) can lead to a broad structural diversity in the solid-state. In Ag(I)eNHC clusters complexes, d 10 ed 10 interactions are often encountered [28,29], while the coordination geometry around the Ag(I) cations may deviate from linear to trigonal or even tetr...

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Microwave‐Assisted Synthesis of (N‐Heterocyclic carbene)MCl Complexes of Group 11 Metals

Abstract: The use of microwave heating for the synthesis of (N-heterocyclic carbene)-bearing complexes of Cu, Ag and Au allows for a drastic reduction of the reaction times required by con-

Cited by 48 publications

References 18 publications

Copper(I) Complexes Bearing Carbenes Beyond Classical N‐Heterocyclic Carbenes: Synthesis and Catalytic Activity in “Click Chemistry”

Copper(I) Complexes Bearing Carbenes Beyond Classical N‐Heterocyclic Carbenes: Synthesis and Catalytic Activity in “Click Chemistry”

Acid, silver, and solvent-free gold-catalyzed hydrophenoxylation of internal alkynes

Silver(I) and copper(I) complexes with bis-NHC ligands: Dinuclear complexes, cubanes and coordination polymers

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