Co-reporter:Wei Zhou, Min Zhang, Hanhui Li, and Wanzhi Chen
Organic Letters 2017 Volume 19(Issue 1) pp:10-13
Publication Date(Web):December 14, 2016
DOI:10.1021/acs.orglett.6b02850
A number of enamine-functionalized 1,2,3-triazole derivatives have been prepared via the Cu-catalyzed three-component reaction of terminal alkyne, azide, and 2H-azirine. The reaction proceeds through insertion of vinyl nitrene into the C–Cu bond of the triazolyl-Cu species, providing an efficient and step- and atom-economic approach to the enamine-bearing polysubstituted 1,2,3-triazoles. The resulting triazoles were easily transformed to trisubstituted pyrazoles in the presence of a Rh catalyst.
Co-reporter:Shixian Zhao, Junshi Wu, Wanzhi Chen
Journal of Organometallic Chemistry 2017 Volume 848(Volume 848) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.jorganchem.2017.07.026
•Metal complexes of N-heterocyclic carbenes containing a heteroarene linker.•Synthesis and structures of polydentate NHC ligands.•C-C and C-N couplings catalyzed by metal NHC complexes.Heteroarene-linked bis(N-heterocyclic carbenes) constitute an important family of ligands in transition metal chemistry and homogeneous catalysis. These ligands are used as multidentate ligands for the construction of mononuclear and multinuclear complexes that show unique physical properties and that are efficient catalysts for many organic transformations. A number of transition metal complexes of heteroarene-linked bis(N-heterocyclic carbene) ligands have been synthesized and structurally characterized in recent decades. In this review, we summarize the recent developments in metal complexes supported by heteroarene-linked bis(N-heterocyclic carbene) ligands and their applications. The ligands and their complexes are categorized by the linkers between the two NHCs, such as pyridine, bipyridine, phenanthroline, naphthyridine, pyrazole, thiophene, and pyridazine.Download high-res image (240KB)Download full-size image
Co-reporter:Min Zhang;Feifei Wu;Huanhong Wang;Junshi Wu
Advanced Synthesis & Catalysis 2017 Volume 359(Issue 16) pp:2768-2772
Publication Date(Web):2017/08/17
DOI:10.1002/adsc.201700387
AbstractCopper-catalyzed sequential 1,3-dipolar cycloadditions of azomethine imines and alkynes and electrophilic thiolations are described. The C−S, C−N, and C−C bonds were simultaneously formed in one pot, leading to N,N-bicyclic pyrazolidinones in good to excellent yields. The process is proposed to proceed via reaction of a cuprate pyrazolidinonate intermediate and benzenesulfonothioate.
Co-reporter:Shaojin Gu;Jiehao Du;Jingjing Huang;Yun Guo;Ling Yang;Weilin Xu
Dalton Transactions 2017 vol. 46(Issue 2) pp:586-594
Publication Date(Web):2017/01/03
DOI:10.1039/C6DT03944H
This report describes the synthesis and characterization of a family of unsymmetrical NCN pincer Ni(II) complexes 2–8 with NHC-triazole arms. All of these complexes have been fully characterized by X-ray single crystal analysis, NMR spectroscopy, and elemental analysis. Complexes 2 and 4–6 were square planar with a chloride trans to the carbene carbon atoms. Complex 3 was a paramagnetic octahedral complex with its central metal surrounded by two NCN pincer ligands. Complexes 7 and 8 contain [(NHC)2Ni2-OH] moieties bearing a OH bridge. Both the [(NHC)2Ni2-OH] complexes 7 and 8 and [(NCNHCN)Ni-Cl] complexes 2 and 4–6 were synthesized similarly via the reactions of the in situ formed Ag–NHCs from the corresponding imidazolium salts with [NiCl2(PPh3)2]. The catalytic activities of all complexes for Suzuki–Miyaura cross-coupling were examined. Under the optimized conditions, complex 4 was active in the Suzuki–Miyaura cross-coupling reactions of aryl iodides and aryl bromides at 110 °C. Aryl chlorides were successfully coupled in the presence of triphenylphosphine as an additive.
Co-reporter:Shixian Zhao, Feifei Wu, Yuyu Ma, Wanzhi Chen, Miaochang Liu and Huayue Wu
Organic & Biomolecular Chemistry 2016 vol. 14(Issue 8) pp:2550-2555
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5OB02397A
A few rhodium complexes of N-heterocyclic carbenes were prepared through carbene transfer reactions and their structures were characterized by X-ray diffraction analysis. The rhodium complexes of NHCs are found to be efficient catalysts for vinylation of various triazoles via C–H activation. A number of double vinylated triazoles can be obtained in good yields.
Co-reporter:Feifei Wu, Yun Zhao, Wanzhi Chen
Tetrahedron 2016 Volume 72(Issue 49) pp:8004-8008
Publication Date(Web):8 December 2016
DOI:10.1016/j.tet.2016.10.032
Cobalt-catalyzed reactions of triazoles and dioxazol-5-one involving nitrene transfer were described. A number of amidated 1,2,3-trizole derivatives have been obtained in moderate to excellent yields.
Co-reporter:Shanfei Pan, Feifei Wu, Ruicheng Yu, and Wanzhi Chen
The Journal of Organic Chemistry 2016 Volume 81(Issue 4) pp:1558-1564
Publication Date(Web):January 25, 2016
DOI:10.1021/acs.joc.5b02710
A palladium-catalyzed, norbornene-mediated acylation/cyanation reaction of iodobenzene was developed by the use of acyl chlorides as acylation reagents and cuprous cyanide. The reaction gave the 2-cyanoaryl ketones efficiently by using readily available starting materials.
Co-reporter:Shixian Zhao, Ruicheng Yu, Wanzhi Chen, Miaochang Liu, and Huayue Wu
Organic Letters 2015 Volume 17(Issue 11) pp:2828-2831
Publication Date(Web):May 26, 2015
DOI:10.1021/acs.orglett.5b01247
Rhodium-catalyzed annulation reactions between triazoles and internal alkynes, leading to various mesoionic isoquinoliums, are described. The reaction involves sequential triazole-directed C–H activation and C–C, C–N, and C–O bond formation processes in a one-pot manner. The starting materials and catalysts are easily available. The reaction offers a facile and practical approach to mesoionic isoquinolium derivatives.
Co-reporter:Xueji Ma, Feifei Wu, Xiaofei Yi, Hangxiang Wang and Wanzhi Chen
Chemical Communications 2015 vol. 51(Issue 31) pp:6862-6865
Publication Date(Web):13 Mar 2015
DOI:10.1039/C5CC01271F
Intramolecular sp3 C–H insertion reaction of α-imino rhodium carbene generated from N-sulfonyl-1,2,3-triazoles has been described. A number of 2,3-dihydrobenzofuran and benzofuran derivatives have been obtained in good to excellent yields.
Co-reporter:Shanfei Pan;Xueji Ma;Danni Zhong;Miaochang Liu;Huayue Wu
Advanced Synthesis & Catalysis 2015 Volume 357( Issue 14-15) pp:3052-3056
Publication Date(Web):
DOI:10.1002/adsc.201500381
Co-reporter:Bo Liu, Xueji Ma, Feifei Wu and Wanzhi Chen
Dalton Transactions 2015 vol. 44(Issue 4) pp:1836-1844
Publication Date(Web):27 Nov 2014
DOI:10.1039/C4DT02986K
A direct and practical synthetic route to N-heterocyclic carbene copper complexes of [(NHC)CuX] (X = halide) and [(NHC)2Cu]PF6 types using commercially available copper powder is described. A number of copper-NHC complexes have been obtained in a range of yields from 26 to 99%. The reactions take place in air without removal of moisture and oxygen, and the excess of copper powder can be easily removed via simple filtration after completion. The direct reactions of imidazolium salts and copper powder can also be performed in aqueous media avoiding tedious purification processes. The procedure is also suitable for gram-scale preparation.
Co-reporter:Chao Chen, Qinqin Xia, Huayu Qiu, Wanzhi Chen
Journal of Organometallic Chemistry 2015 Volume 775() pp:103-108
Publication Date(Web):1 January 2015
DOI:10.1016/j.jorganchem.2013.11.037
•We prepared palladium polysulfide complexes of N-heterocyclic carbenes.•The structures of the NHC complexes consisting of S42−, S52−, and S22− anions were characterized.•The structures vary depending upon the 1,1′-di(R)-3,3′-methylenediimidazolin-2,2′-diylidene ligands.Palladium(II) polysulfide complexes [(PdL)4(μ4-S2)2](PF6)4, [PdL(μ2-S4)], [(PdL)2(μ4-S5)](PF6)2, and [(PdL)3(μ3-S)2](PF6)2 have been synthesized through the reactions of [PdL(NH3)2](PF6)2 and [PdL(CH3CN)2](PF6)2 (L = 1,1′-di(R)-3,3′-methylenediimidazolin-2,2′-diylidene, R = methyl, ethyl, isopropyl, and mesityl) with element sulfur, thiourea or (Bu4N)2S6, respectively. [(PdL)4(μ4-S2)2](PF6)4 features four [PdL]2+ units joined by two S22− ligands in which each sulfur bonds to two palladium ions. The neutral complexes [PdL(μ2-S4)] consist of a S42− chain anion chelated to the palladium ion with two terminal sulfur atoms. In [(PdL)2(μ4-S5)](PF6)2 two [Pd]2+ units are held together by a S52− ligand forming two six-membered [PdS5] rings with chair and boat conformation. Trinuclear complex [(PdL2)3(μ3-S)2](PF6)2 contains three [PdL]2+ units held by two tridenate S2− ions forming a trigonal bipyramidal Pd3S2 structure.Palladium(II) polysulfide complexes containing μ4-S22−, μ2-S42−, μ4-S52−, and μ3-S2− ions have been synthesized through the reactions of [PdL(NH3)2](PF6)2 and [PdL(CH3CN)2](PF6)2 (L = 1,1′-di(alkyl)-3,3′-methylenediimidazolin-2,2′-diylidene, L1-L4, alkyl = methyl, ethyl, isopropyl, and Mes) with element sulfur, thiourea or (Bu4N)2S6, respectively.
Co-reporter:Xueji Ma, Shanfei Pan, Hangxiang Wang, and Wanzhi Chen
Organic Letters 2014 Volume 16(Issue 17) pp:4554-4557
Publication Date(Web):August 21, 2014
DOI:10.1021/ol5021042
Rhodium-catalyzed transannulation of 1,2,3-triazoles and ring-opening reactions of epoxides is described. A number of 3,4-dihydro-2H-1,4-oxazines are obtained in moderate yields probably involving generation of α-imino rhodium(II) carbene species.
Co-reporter:Bo Liu, Shanfei Pan, Bin Liu, and Wanzhi Chen
Inorganic Chemistry 2014 Volume 53(Issue 19) pp:10485-10497
Publication Date(Web):September 12, 2014
DOI:10.1021/ic501544d
Co-reporter:Bo Liu, Miaochang Liu, Huayue Wu, Wanzhi Chen
Journal of Organometallic Chemistry 2014 Volumes 772–773() pp:113-121
Publication Date(Web):1 December 2014
DOI:10.1016/j.jorganchem.2014.09.007
•Polynuclear Ag complexes of phenanthroline-functionalized NHCs are presented.•The Ag–NHC complexes were characterized by NMR and X-ray techniques.•The Ag–NHC complexes are emissive.A few polynuclear silver(I)–NHC complexes have been synthesized via the reactions of phenanthroline-functionalized imidazolium salts with Ag2O at room temperature. The structures of di-, tri-, and tetranuclear silver complexes were fully characterized. The two N-phenanthrolinylimidazolylidene ligands in [Ag4(L1)4](PF6)4 (1), [Ag2(L2)2](PF6)2 (2), and [Ag2(L3)2](PF6)2 (3) are head-to-head arranged. Complex 1 contains a short ligand-unsupported Ag–Ag bond being 3.152(1) Å representing the first example of strictly linear Ag4 cluster stabilized by NHCs. Trinuclear [Ag3(L4)2](PF6)3 (4) of phenanthroline-bridged biscarbene ligands contains a linearly arranged Ag3 core. [Ag3(L5)2](PF6)3 (5) and [Ag3(L4)2](PF6)3 (7) are also trinulear Ag(I) complexes. Binuclear [Ag2(L6)2](PF6)2 (6) exhibits a twisted macrocyclic structure with the Ag–Ag separation at 3.162(1) Å. In 1–4, the silver ions are held together by two ligands in close proximity with the Ag–Ag distances between 2.810(1) and 2.922(1) Å. The fluorescent properties of these silver complexes have also been briefly studied.A few polynuclear silver complexes of phenanthroline-functionalized NHCs have been prepared and their structures were characterized by NMR and X-ray techniques. The Ag–NHC complexes are emissive.
Co-reporter:Xueji Ma, Hangxiang Wang, and Wanzhi Chen
The Journal of Organic Chemistry 2014 Volume 79(Issue 18) pp:8652-8658
Publication Date(Web):August 21, 2014
DOI:10.1021/jo5014228
A small library of water-soluble N-heterocyclic carbene (NHC)-stabilized palladium complexes was prepared and applied for cross-couplings of biomolecules under mild conditions in water. Pd–NHC complexes bearing hydrophilic groups were demonstrated to be efficient catalysts for the Suzuki–Miyaura coupling of various unnatural amino acids and proteins bearing p-iodophenyl functional groups. We further utilized this catalytic system for the rapid bioorthogonal labeling of proteins on the surfaces of mammalian cells. These results demonstrated that NHC-stabilized metal complexes have potential utility in cellular systems.
Co-reporter:Xiaobo Shang, Chao Chen, Huayu Qiu, Wanzhi Chen
Tetrahedron 2014 70(18) pp: 3073-3077
Publication Date(Web):
DOI:10.1016/j.tet.2014.02.031
Co-reporter:Xiaobo Shang;Shixian Zhao;Dr. Wanzhi Chen;Dr. Chao Chen;Dr. Huayu Qiu
Chemistry - A European Journal 2014 Volume 20( Issue 7) pp:1825-1828
Publication Date(Web):
DOI:10.1002/chem.201303712
Abstract
A new approach to the synthesis of 2 H-benzotriazoles is described. This strategy is based on the copper-catalyzed CN coupling of 2-haloaryltriazenes or 2-haloazo compounds with sodium azide and the intramolecular addition of nitrene to NN bonds. This approach allows the synthesis of various N-amino- and N-aryl-2 H-benzotriazoles in water, in good to excellent yields. The procedure is simple and the starting materials and catalyst are easily available, offering a practical and convenient synthetic route to 2-substituted benzotriazoles.
Co-reporter:Qinqin Xia, Xiaolong Liu, Yuejiao Zhang, Chao Chen, and Wanzhi Chen
Organic Letters 2013 Volume 15(Issue 13) pp:3326-3329
Publication Date(Web):June 21, 2013
DOI:10.1021/ol401362k
The copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagent are described. Various amides and carboxylic acids were methylated affording N-substituted amides and esters. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process.
Co-reporter:Yuansong Jiang, Wanzhi Chen, Weimin Lu
Tetrahedron 2013 69(18) pp: 3669-3676
Publication Date(Web):
DOI:10.1016/j.tet.2013.03.025
Co-reporter:Bo Liu ; Congyan Chen ; Yuejiao Zhang ; Xiaolong Liu
Organometallics 2013 Volume 32(Issue 19) pp:5451-5460
Publication Date(Web):September 26, 2013
DOI:10.1021/om400738c
We have prepared a number of phenanthroline-functionalized imidazolium and triazolium salts from 2-iodo-1,10-phenanthroline and imidazole and triazole derivatives. Simple reactions of these imidazolium salts with copper powder at room temperature have afforded a series of dinuclear copper(I)-NHC complexes doubly bridged by N-(1,10-phenanthrolin-2-yl)imidazolylidene ligands in excellent yields. The two phen-NHC ligands are either head-to-head or head-to-tail arranged depending upon the steric repulsion of the substituents. Reactions of imidazolium halides and copper yielded dinuclear complexes [Cu2(μ-X)(L6)2]X (X = Cl, Br, I) in nearly quantitative yields. The dinuclear [Cu2(L10)2(μ-MeCN)]2+ was similarly obtained through 1,2,4-triazolium salts and copper, and the compound consists of a bridging CH3CN molecule, representing the first example of Cu-NHC complexes with a 3c–2e bond. These Cu(I) complexes have been characterized by NMR spectra and elemental analysis and further confirmed by X-ray diffraction analysis. These dinuclear copper-NHC complexes are highly active for cycloaddition reaction of alkynes and azides at room temperature. [Cu2(μ-X)(L6)2]X are the most efficient catalysts among these dinuclear complexes in acetonitrile, which are superior to the commonly used copper catalysts for click reaction.
Co-reporter:Xiaolong Liu, Shanfei Pan, Junshi Wu, Yapei Wang, and Wanzhi Chen
Organometallics 2013 Volume 32(Issue 1) pp:209-217
Publication Date(Web):December 26, 2012
DOI:10.1021/om3009876
HL·(PF6) (L = 2,4-dimethyl-8-phenyl[1,2,4]triazolo[4,3-a][1,8]naphthyridin-9-ylidene) was synthesized from the nucleophilic reaction of 7-chloro-2,4-dimethyl-1,8-naphthyridine with phenylhydrazine and subsequent acidification, anion exchange, and condensation with triethyl orthoformate. Its silver, copper, cobalt, and nickel complexes [Ag2(L)2(CH3CN)2](PF6)2 (1), [CuL(CH3CN)2](PF6) (2), [CuL(phen)](PF6) (3), [CuL(dppe)](PF6) (4), [Co(L)2(CH3CN)2](PF6)2 (5), and [Ni(L)3](PF6)2 (6) have been synthesized and fully characterized by NMR, elemental analysis, and X-ray diffraction analysis. The copper complex 2 exhibits excellent catalytic activity in the Cu(I)-catalyzed azide–alkyne cycloaddition reaction of 2,2,6,6-tetramethylpiperidinyl-1-oxy-tethered alkynes in an air atmosphere at 50 °C.
Co-reporter:Xiaolong Liu, Qinqin Xia, Yuejiao Zhang, Congyan Chen, and Wanzhi Chen
The Journal of Organic Chemistry 2013 Volume 78(Issue 17) pp:8531-8536
Publication Date(Web):August 14, 2013
DOI:10.1021/jo401252d
Imidazolium salts bearing TEMPO groups react with commercially available copper powder affording Cu-NHC complexes. The in situ generated Cu-NHC-TEMPO complexes are quite efficient catalysts for aerobic oxidation of primary alcohols into aldehydes. The catalyst is easily available, and various primary alcohols were selectively converted to aldehydes in excellent yields.
Co-reporter:Shaojin Gu, Bo Liu, Jiuxi Chen, Huayue Wu and Wanzhi Chen
Dalton Transactions 2012 vol. 41(Issue 3) pp:962-970
Publication Date(Web):17 Nov 2011
DOI:10.1039/C1DT11269D
Mononuclear ruthenium complexes [RuCl(L1)(CH3CN)2](PF6) (2a), [RuCl(L2)(CH3CN)2](PF6) (2b), [Ru(L1)(CH3CN)3](PF6)2 (4a), [Ru(L2)(CH3CN)3](PF6)2 (4b), [Ru(L2)2](PF6)2 (5), [RuCl(L1)(CH3CN)(PPh3)](PF6) (6), [RuCl(L1)(CO)2](PF6) (7), and [RuCl(L1)(CO)(PPh3)](PF6) (8), and a tetranuclear complex [Ru2Ag2Cl2(L1)2(CH3CN)6](PF6)4 (3) containing 3-(1,10-phenanthrolin-2-yl)-1-(pyridin-2-ylmethyl)imidazolylidene (L1) and 3-butyl-1-(1,10-phenanthrolin-2-yl)imidazolylidene (L2) have been prepared and fully characterized by NMR, ESI-MS, UV-vis spectroscopy, and X-ray crystallography. Both L1 and L2 act as pincer NNC donors coordinated to ruthenium (II) ion. In 3, the Ru(II) and Ag(I) ions are linked by two bridging Cl− through a rhomboid Ag2Cl2 ring with two Ru(II) extending to above and down the plane. Complexes 2–8 show absorption maximum over the 354–428 nm blueshifted compared to Ru(bpy)32+ due to strong σ-donating and weak π-acceptor properties of NHC ligands. Electrochemical studies show Ru(II)/Ru(III) couples over 0.578–1.274 V.
Co-reporter:Xiaolong Liu and Wanzhi Chen
Dalton Transactions 2012 vol. 41(Issue 2) pp:599-608
Publication Date(Web):03 Nov 2011
DOI:10.1039/C1DT11356A
A family of hexa-coordinated ruthenium(II) complexes of bis(N-pyridylimidazolylidenyl)methane (L) were prepared and structurally characterized. Carbene transfer reactions of [Ru(p-cymene)Cl2]2, [Ru(CO)2Cl2]n and RuHCl(CO)(PPh3)3 with silver–NHC complexes in situ generated from [H2L](PF6)2 and Ag2O afforded [RuL(CH3CN)2](PF6)2 (1), [Ru2L(p-cymene)2Cl2](PF6)2 (2), [RuL(CO)2](PF6)2 (3) and [RuL(PPh3)2](PF6)2 (4), respectively. The reactions of 1 towards several N- and P-donors were studied. The treatment of 1 with 1,10-phenanthroline resulted in the substitution of one pyridine and one acetonitrile molecule affording [RuL(phen)(CH3CN)](PF6)2 (5) as a mixture of two isomers. Reaction of 1,2-bis(diphenylphosphino)ethane (dppe) and 1 gave [RuL(dppe)(CH3CN)2](PF6)2 (7), in which two pyridines were substituted by a dppe ligand trans to two NHC groups. In contrast, reactions of 1 with ethane-1,2-diamine, propane-1,3-diamine and 3,5-dimethyl-1H-pyrazole led to the substitution of acetonitrile and subsequent N–H addition of the CN bond of the coordinated acetonitrile yielding [RuL(ethane-1,2-diamine)(N-(2-aminoethyl)acetimidamide)](PF6)2 (8), [RuL(propane-1,3-diamine)(N-(3-aminopropyl)acetimidamide)](PF6)2 (9) and RuL(1-(3,5-dimethyl-1H-pyrazol-1-yl)ethanimine)(CH3CN)](PF6)2 (10), respectively.
Co-reporter:Chao Chen, Wanzhi Chen and Huayu Qiu
Dalton Transactions 2012 vol. 41(Issue 43) pp:13405-13412
Publication Date(Web):04 Sep 2012
DOI:10.1039/C2DT31739G
The reaction of neutral palladium complexes PdLBr2 (L = 1,1′-di(alkyl)-3,3′-methylenediimidazolin-2,2′-diylidene) with NH4PF6 in CH3CN afforded [PdL(NH3)2](PF6)2 (1–3, L1, alkyl = Me; L2, alkyl = Et; L3, alkyl = iso-Pr) and [PdL4(CH3CN)2](PF6)2 (4, alkyl = Mes). Treatment of [PdL(NH3)2](PF6)2 complexes with N-donors, 9-ethyl-3,6-diimidazolyl-carbazole (dicz), mercaptopyridine (HSPy), 3,5-dimethyl-1H-pyrazole (Hdmpz), and 1,2-dibenzoylhydrazine (H2dbhz) resulted in the substitution of NH3 forming dinuclear palladium complexes [PdL1(dicz)]2(PF6)4 (5), [PdL1(SPy)]2(PF6)2 (6), [PdL2(dmpz)]2(PF6)2 (7), [(PdL2)2(dbhz)] (8). Reaction of [PdL2(NH3)2](PF6)2 with hydrazine led to a mixture of [Pd(L2)2](PF6)2 (9) and [PdL2(NH2NC(CH3)NHNH2)](PF6)2 (10). The NH2NC(CH3)NHNH2 moiety was formed in situ by nucleophilic addition to CH3CN by two molecules of NH2NH2 and subsequent NH3 elimination. All of these complexes have been fully characterized by ESI-MS, NMR spectroscopy, and elemental analysis. The molecular structures of 1 and 5–10 were also studied by X-ray diffraction analysis.
Co-reporter:Daichao Xu, Chunxin Lu, Wanzhi Chen
Tetrahedron 2012 68(5) pp: 1466-1474
Publication Date(Web):
DOI:10.1016/j.tet.2011.12.017
Co-reporter:Xiaolong Liu and Wanzhi Chen
Organometallics 2012 Volume 31(Issue 18) pp:6614-6622
Publication Date(Web):August 31, 2012
DOI:10.1021/om300644h
[Ru2Cl(L)(CH3CN)4](PF6)3 (1, L = 3,6-bis(N-(pyridylmethyl)imidazolylidenyl)pyridazine), [Cu3La3](PF6)3 (2, La = 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl)imidazolylonyl)pyridazine), [Pd2(allyl)2L](PF6)2 (3), [Pd2(allyl)2Lb2](PF6)2 (4, Lb = N-pyridylmethylimidazole), and [NiLc2](PF6)2 (5, Lc = 3-(N-(pyridylmethyl)imidazolylidenyl)-6-methoxylpyridazine) have been synthesized and fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. In complex 1, ligand L binds to two Ru(II) centers, forming a well-behaved Ru2(L)Cl plane with a five-membered metallocyclic ring. Complex 2 is trinuclear, containing a triangular Cu3 unit bonded together by three 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl)imidazolylonyl)pyridazine, where one imidazolylidene was oxidized into imidazolone. Deprotonation reaction with Ag2O in CH3CN and CH3OH resulted in C–N cleavage of the imidazolium salt, and subsequent reaction with [Pd(allyl)Cl]2 and Ni(PPh3)2Cl2 gave 4 and 5, respectively. Dinuclear Ru(II)-NHC complex 1 exhibits excellent catalytic activity for the oxidation of alkenes into diketones.
Co-reporter:Qinqin Xia and Wanzhi Chen
The Journal of Organic Chemistry 2012 Volume 77(Issue 20) pp:9366-9373
Publication Date(Web):October 1, 2012
DOI:10.1021/jo301568e
Iron-catalyzed direct C–N bond formation between azoles and amides is described. The oxidative coupling reactions of sp3 C–H bonds adjacent to a nitrogen atom in amides and sulfonamides with the N–H bond in azoles proceeded smoothly in the presence of FeCl2 and di-tert-butyl peroxide (DTBP).
Co-reporter:Yin Zhang;Bin Liu;HuaYue Wu
Science Bulletin 2012 Volume 57( Issue 19) pp:2368-2376
Publication Date(Web):2012 July
DOI:10.1007/s11434-012-5164-5
Reactions of [FeL2(CH3CN)2]2+ (L = N-pyrimid-2-ylimidazolylidene) with various N-, P-, O-, and S-donors were investigated. By replacing the labile acetonitrile, various iron-NHC complexes containing additional N-, P-, O-, and S-ligands were prepared. All the iron-NHC complexes were fully characterized by NMR spectroscopy and X-ray crystallography. [FeL2(CH3CN)2]2+ could efficiently catalyze the coupling reactions of various Grignard reagents with heteroaryl bromides or chlorides.
Co-reporter:Bo Liu, Xiaolong Liu, Chao Chen, Congyan Chen, and Wanzhi Chen
Organometallics 2012 Volume 31(Issue 1) pp:282-288
Publication Date(Web):December 29, 2011
DOI:10.1021/om200881s
We describe a new synthetic procedure for transition-metal N-heterocyclic carbene complexes (NHCs). A number of Pd(II), Pt(II), Co(III), and Ru(II) complexes containing functionalized NHCs have been obtained in good to excellent yields using NiII–NHC complexes as carbene transfer reagents. NiII–NHC complexes are easily prepared from the direct reactions of the corresponding imidazolium salts with commercially available Raney nickel powder. The byproduct of transmetalation reactions, NiCl2, can be easily removed by simple filtration. This study offers a new, economical, and practical synthetic method for metal–NHC complexes.
Co-reporter:Chao Chen, Huayu Qiu, Wanzhi Chen
Journal of Organometallic Chemistry 2012 696(26) pp: 4166-4172
Publication Date(Web):
DOI:10.1016/j.jorganchem.2011.09.008
Co-reporter:Bin Liu, Yin Zhang, Daichao Xu and Wanzhi Chen
Chemical Communications 2011 vol. 47(Issue 10) pp:2883-2885
Publication Date(Web):18 Jan 2011
DOI:10.1039/C0CC05260D
A novel electrochemical procedure for the preparation of metal complexes of N-heterocyclic carbenes using imidazolium salts or corresponding silver–NHC complexes as carbene sources and electrolytes, and metal plates as the sacrificial anodes is described. The procedure is simple and good yielding without the use of expensive or air-sensitive reagents.
Co-reporter:Chao Chen, Huayu Qiu, and Wanzhi Chen
Inorganic Chemistry 2011 Volume 50(Issue 17) pp:8671-8678
Publication Date(Web):July 27, 2011
DOI:10.1021/ic2012233
Three metallacrown nickel complexes [Ni3(μ-OH)(L1)3](PF6)2 (1, L1 = 3-((N-methylimidazolylidenyl)methyl)-5-methylpyrazolate), [Ni3(μ-OH)(L2)3](PF6)2 (2, L2 = 3-((N-mesitylimidazolylidenyl)methyl)-5-methylpyrazolate), and [Ni3(μ-OH)(L3)3](PF6)2 (3, L3 = 3-((N-pyrimidin-2-ylimidazolylidenyl)methyl)-5-methylpyrazolate) were obtained by the reactions of corresponding silver–NHC complexes with Raney nickel powder at 45 °C. The same reaction at 80 °C afforded [Ni3(L2)4](PF6)2 (4). The carbene-transfer reaction of the silver–carbene complex with [(η3-C3H5)PdCl]2 yielded the heterotrimetallic complex [AgPd2(η3-C3H5)2(L2)2](PF6) (5), whereas the carbene-transfer reaction with Pt(cod)Cl2 gave [Pt2(L3)2](PF6)2 (6). All of these complexes have been fully characterized by ESI-MS, NMR spectroscopy, and elemental analysis. The molecular structures of 1–6 were also studied by X-ray diffraction analysis. In 1–3, three nickel centers are bridged together by three pyrazole–NHC ligands and a hydroxide group, forming a 9-metallacrown-3 topology. Complex 4 is paramagnetic, consisting of two square-planar nickel(II) ions and one tetrahedral nickel ion in which three Ni ions are bridged by four pyrazolate units. In the mixed Pd–Ag complex 5, two palladium and one silver centers are bridged by two pyrazole–NHC ligands. Complex 5 showed good catalytic activity in the Sonogashira coupling reaction of aryl bromides and phenylacetylene under mild conditions typically catalyzed by Pd–Cu systems.
Co-reporter:Shaojin Gu, Daichao Xu and Wanzhi Chen
Dalton Transactions 2011 vol. 40(Issue 7) pp:1576-1583
Publication Date(Web):07 Jan 2011
DOI:10.1039/C0DT01211D
Mono- and polynuclear complexes containing 3-(1,10-phenanthrolin-2-yl)-1-(pyridin-2-ylmethyl)imidazolylidene (L), [NiL2](PF6)2 (2), [CoL2](PF6)3 (3), [PtLCl](PF6) (4), [PdAgL2](PF6)3 (5), [PdCuL2](PF6)3 (6), [Pd2L2Cl2](PF6)2 (7), and [Pd3L2Cl4](PF6)2 (8) have been prepared and fully characterized by NMR, ESI-MS spectroscopy, and X-ray crystallography. In complexes 2–4, the ligand binds to metals in a pincer NNC fashion with the pyridine group uncoordinated. Complexes 5 and 6 are isostructural to each other in which the palladium ions are surrounded by two pyridines and two imidazolylidenes and Ag(I) or Cu(I) is coordinated by two 1,10-phenanthroline moieties. In the trinuclear palladium complex 8, one palladium ion has an identical coordination mode as in 5 and 6, and the other two palladium ions are bonded to the 1,10-phenanthroline. Complex 6 exhibits excellent catalytic activity for the tandem click/Sonogashira reaction of 1-(bromomethyl)-4-iodobenzene, NaN3, and ethynylbenzene in which three C–N bonds and one C–C bond are formed in a single flask.
Co-reporter:Hui Xu, Shaojin Gu, Wanzhi Chen, Dacheng Li, and Jianmin Dou
The Journal of Organic Chemistry 2011 Volume 76(Issue 8) pp:2448-2458
Publication Date(Web):March 16, 2011
DOI:10.1021/jo2000176
An efficient synthesis of trisubstituted alkenes including 1,2-heterodisubstituted alkenes has been described. Reactions of thiols and amines with 1,1-dibromo-1-alkenes in the presence of TBAF·3H2O afford (Z)-2-bromovinyl sulfides and (Z)-2-bromovinyl amines regio- and stereoselectively. The reaction proceeds under catalyst-free conditions with high efficiency. The coupling reactions of the obtained products bearing bromine atoms with phenylacetylene and phenylboronic acid gave trisubstituted alkenes in good to excellent yields. Cross-coupling with various N, O, S, and P nucleophiles selectively generated 1,2-N,O, 1,2-N,S, 1,2-S,P, 1,2-S,S, and 1,2-S,O heterodisubstituted alkenes.
Co-reporter:Qinqin Xia, Wanzhi Chen, and Huayu Qiu
The Journal of Organic Chemistry 2011 Volume 76(Issue 18) pp:7577-7582
Publication Date(Web):July 29, 2011
DOI:10.1021/jo201253m
Iron-catalyzed direct C–N bond formation between imidazoles and benzylic hydrocarbons is described. The reaction utilizes an inexpensive iron catalyst–oxidant system that is suitable for the coupling of a range of benzylic C–H bonds with various imidazoles.
Co-reporter:Hui Xu, Yin Zhang, Jianqiang Huang and Wanzhi Chen
Organic Letters 2010 Volume 12(Issue 16) pp:3704-3707
Publication Date(Web):July 29, 2010
DOI:10.1021/ol101563f
The first aminothiolation of 1,1-dibromoalkene is described using an inexpensive copper/N,N-dimethylethylenediamine catalyst. The method provides a powerful means of using easily available 1,1-dihaloalkenes as precursors to fused heterocycles.
Co-reporter:Chunxin Lu, Shaojin Gu, Wanzhi Chen and Huayu Qiu
Dalton Transactions 2010 vol. 39(Issue 17) pp:4198-4204
Publication Date(Web):24 Mar 2010
DOI:10.1039/B924587A
The platinum(II) complexes of multidentate N-heterocyclic carbenes, [Pt(L1)2Cl](PF6) (1, L1 = N-methyl-N-(2-pyrimidinyl)imidazolylidene), [Pt(L2)Cl](PF6) (2, L2 = N-butyl-N-(1,10-phenanthrolin-2-yl)imidazolylidene), [PtL3](PF6)2 (3, L3 = bis(N-picolylimidazolylidenyl)methane), [PtL4](PF6)2 (4, L4 = (bis(N-2-pyrimidylimidazolylidenyl)methane) (4) and [Pt(L5)2](PF6)2 [5, L5 = bis(N-pyridylimidazoliumyl)methane] have been synthesized and structurally characterized. All these complexes exhibit slightly distorted square-planar configuration. These complexes are efficient catalyst precursors for hydrosilylation of alkynes. Complexes 2 and 4 are much more active than complexes 1, 3 and 5. In the hydrosilylation of arylacetylenes, relatively long induction periods were observed for 1, 3 and 5.
Co-reporter:Shaojin Gu;Hui Xu;Na Zhang Dr. Dr.
Chemistry – An Asian Journal 2010 Volume 5( Issue 7) pp:1677-1686
Publication Date(Web):
DOI:10.1002/asia.201000071
Abstract
Imidazolium salts bearing triazole groups are synthesized via a copper catalyzed click reaction, and the silver, palladium, and platinum complexes of their N-heterocyclic carbenes are studied. [Ag4(L1)4](PF6)4, [Pd(L1)Cl](PF6), [Pt(L1)Cl](PF6) (L1=3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-1-(pyrimidin-2-yl)-1H-imidazolylidene), [Pd2(L2)2Cl2](PF6)2, and [Pd(L2)2](PF6)2 (L2=1-butyl-3-((1-(pyridin-2-yl)-1H-1,2,3-triazol-4-yl)methyl)imidazolylidene) have been synthesized and fully characterized by NMR, elemental analysis, and X-ray crystallography. The silver complex [Ag4(L1)4](PF6)4 consists of a Ag4 zigzag chain. The complexes [Pd(L1)Cl](PF6) and [Pt(L1)Cl](PF6), containing a nonsymmetrical NCN′ pincer ligand, are square planar with a chloride trans to the carbene donor. [Pd2(L2)2Cl2](PF6)2 consists of two palladium centers with CN2Cl coordination mode, whereas the palladium in [Pd(L2)2](PF6)2 is surrounded by two carbene and two triazole groups with two uncoordinated pyridines. The palladium compounds are highly active for Suzuki–Miyaura cross coupling reactions of aryl bromides and 1,1-dibromo-1-alkenes in neat water under an air atmosphere.
Co-reporter:Xiaoming Zhang, Weilong Xie, Wanzhi Chen
Tetrahedron 2010 66(6) pp: 1188-1195
Publication Date(Web):
DOI:10.1016/j.tet.2009.12.043
Co-reporter:Bo Liu, Bin Liu, Yongbo Zhou and Wanzhi Chen
Organometallics 2010 Volume 29(Issue 6) pp:1457-1464
Publication Date(Web):February 23, 2010
DOI:10.1021/om100009u
Reactions of the imidazolium salts or their corresponding silver carbene complexes with copper powder afforded unusual copper(II) hydroxide complexes of N-heterocyclic carbenes: [Cu2(μ-OH)(L1)](PF6)2 (2; L1 = 3,5-bis(N-picolylimidazolylidenylmethyl)pyrazolate), [Cu4(μ3-OH)2(L2)2](PF6)4 (3; L2 = 3,5-bis(N-pyridylimidazolylidenylmethyl)pyrazolate), and [Cu4(μ3-OH)2(L3)2](PF6)4 (4; L3 = 3,5-bis(N-pyrimidylimidazolylidenylmethyl)pyrazolate). The same reaction of 3,5-bis(N-thiophenylimidazoliumylmethyl)pyrazole yielded a dinuclear Cu(II)−NHC complex, [Cu2(L4)2](PF6)2 (5; L4 = 3,5-bis(N-thiophenylimidazolylidenylmethyl)pyrazolate). The complexes have been fully characterized by X-ray diffraction analysis, elemental analysis, and IR and ESI-MS spectra. A catalytic study shows that complex 4 is highly active in the N-arylation reactions of imidazoles and aromatic amines with arylboronic acids in methanol at room temperature under base-free conditions.
Co-reporter:Zhenxing Xi, Bin Liu, Chunxin Lu and Wanzhi Chen
Dalton Transactions 2009 (Issue 35) pp:7008-7014
Publication Date(Web):06 Jul 2009
DOI:10.1039/B906242D
Cobalt(III) complexes, [CoCl2(L1)2](PF6) (1, L1 = N-methyl-N-(2-pyrimidinyl)imidazolylidene), [CoCl(L2)2](PF6)2 (2, L2 = N-picolyl-(2-pyrimidinyl)imidazolylidene), [Co(L3)2](PF6)3 (3, L3 = bis(N-2-pyrimidylimidazolylidenyl)methane) and [CoCl2(L3)](PF6) (4) have been prepared from the corresponding pyrimidine functionalized imidazolium salts [HL1](PF6), [HL2](PF6), and [H2L3](PF6)2via in situ generated silver carbene complexes under mild conditions. These cobalt complexes were characterized by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. The cobalt complexes have been found to be good catalyst precursors for Kumada–Corriu cross-coupling reactions of aryl halides and Grignard reagents at room temperature. Complex 1 is more active under the mild conditions.
Co-reporter:Xiaoming Zhang, Qinqin Xia and Wanzhi Chen
Dalton Transactions 2009 (Issue 35) pp:7045-7054
Publication Date(Web):29 Jun 2009
DOI:10.1039/B903285A
Palladium complexes, [Pd(1-butyl-3-((7-methyl-1,8-naphthyridin-2-yl)methyl)imidazolylidene)2](PF6)2 (1), [Pd(3-methyl-1-(pyrimidin-2-yl)imidazolylidene)2(CH3CN)](PF6)2 (4), [Pd(3-benzyl-1-(pyrimidin-2-yl)imidazolylidene)2(CH3CN)](PF6)2 (5), [Pd(3-ethyl-1-(pyrimidin-2-yl)imidazolylidene)2Cl](PF6) (6), and [Pd(3-benzyl-1-(pyrimidin-2-yl)imidazolylidene)Cl2] (7), have been prepared viatransmetallation of corresponding in situ generated silver-carbene complexes. These palladium complexes have been characterized by NMR spectroscopy and elemental analyses, and their structures were determined by X-ray single-crystal diffraction. Complexes 1 and 7 are tetracoordinate displaying square-planar geometry. Complexes 4–6 are pentacoordinate showing uncommon square-pyramidal geometry with acetonitrile or chloride at the equatorial position. The Suzuki and Hiyama coupling reactions of a wide range of aryl bromides and chlorides have been comparatively investigated by using tetracoordinate moncarbene, tetracoordinate dicarbene, and pentacoordinate dicarbene palladium complexes as catalysts. The tetracoordinate moncarbene palladium complex showed the highest catalytic activity for both coupling reactions.
Co-reporter:Bin Liu;Qinqin Xia Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 30) pp:5513-5516
Publication Date(Web):
DOI:10.1002/anie.200901850
Co-reporter:Xiaoming Zhang, Bin Liu, Ailing Liu, Weilong Xie and Wanzhi Chen
Organometallics 2009 Volume 28(Issue 5) pp:1336-1349
Publication Date(Web):January 21, 2009
DOI:10.1021/om800982r
A family of tetra-, penta-, and hexacoordinate nickel complexes of functionalized N-heterocyclic carbene (NHC) ligands have been prepared via carbene transfer reactions of Ni(PPh3)2Cl2 and silver-NHC complexes in situ generated from corresponding imidazolium salts and Ag2O. These nickel(II) complexes have been characterized by 1H NMR, 13CNMR, and ESI spectroscopy and X-ray diffraction analysis. Structural analysis revealed that [Ni(L1)3](PF6)2 (L1 = 3-butyl-1-(5,7-dimethyl-1,8-naphthyridin-2-yl)imidazolylidene, 3) is a rare example of a nickel complex with trigonal-bipyramidal geometry. [Ni(L4)2](PF6)2 (L4 = 1-butyl-3-((7-methyl-1,8-naphthyridin-2-yl)methyl)imidazolylidene, 5) and [Ni(L20)2](PF6)2 (L20 = 3-(pyridin-2-ylmethyl)-1-(pyrimidin-2-yl)imidazolylidene, 21) are normal square-planar. [Ni(L8)3](PF6)2 (L8 = 3-methyl-1-(pyrimidin-2-yl)imidazolylidene, 9), [Ni(L10)2(CH3CN)](PF6)2 (L10 = 3-ethyl-1-(pyrimidin-2-yl)imidazol-ylidene, 11), [Ni(L12)2(CH3CN)](PF6)2 (L12 = 3-butyl-1-(pyrimidin-2-yl)imidazolylidene, 13), [Ni(L14)2(CH3CN)](PF6)2 (L14 = 3-benzyl-1-(pyrimidin-2-yl)imidazolylidene, 15), and [Ni(L16)2(CH3CN)](PF6)2 (L16 = 3-isopropyl-1-(pyrimidin-2-yl)imidazolylidene, 17) are pentacoordinate, displaying unusual square-pyramidal geometry. [Ni(L12)3](PF6)2 (L9 = 3-butyl-1-(pyrimidin-2-yl)imidazolylid-ene, 19), [Ni(L22)2(CH3CN)2](PF6)2 (L22 = 3-(2,6-diisopropylphenyl)-1-(pyrimidin-2-yl)imidazolylidene, 23), and [Ni(L24)(CH3CN)(H2O)] (L22 = 3-(2,4,6-trimethylphenyl)-1-(pyrimidin-2-yl)imidazolylidene, 25) are octahedral complexes. The structural diversity of these nickel(II) complexes originating from steric pressure of the ligands is discussed.
Co-reporter:Shaojin Gu and Wanzhi Chen
Organometallics 2009 Volume 28(Issue 3) pp:909-914
Publication Date(Web):January 12, 2009
DOI:10.1021/om801056v
Palladium and nickel complexes, [Pd(L)Cl](PF6) (1), [Ni(L)Cl](PF6) (2), and [Ni(L)2](PF6)2 (3), containing 3-butyl-1-(1,10-phenanthrolin-2-yl)imidazolylidene (L) have been synthesized and fully characterized by NMR and ESI-MS spectroscopy and X-ray diffraction analysis. The unsymmetrical NNC pincer complexes 1 and 2 are square planar with a chloride trans to the internal nitrogen atom of phenanthroline. Complex 3 is a paramagnetic octahedral complex with its central metal surrounded by two pincer ligands. A catalytic study shows that palladium compound 1 is highly active in copper-free Sonogashira cross-coupling reactions of aryl iodides at room temperature and aryl bromides at 80 °C in neat water. The nickel complex 2 exhibits good activity in the Kumada cross-coupling reaction of aryl chloride at room temperature.
Co-reporter:Shaojin Gu, Chao Chen and Wanzhi Chen
The Journal of Organic Chemistry 2009 Volume 74(Issue 18) pp:7203-7206
Publication Date(Web):August 12, 2009
DOI:10.1021/jo901316b
The palladium-catalyzed direct acetoxylation and arylation of 2-aryloxypyrimidine has been described. The aromatic C−H bonds may be functionalized in moderate to excellent yields providing a facile method for the synthesis of phenol derivatives, which show antimycobacterial and herbicidal activities.
Co-reporter:Xiaoming Zhang, Shaojin Gu, Qinqin Xia, Wanzhi Chen
Journal of Organometallic Chemistry 2009 694(15) pp: 2359-2367
Publication Date(Web):
DOI:10.1016/j.jorganchem.2009.03.031
Co-reporter:Bin Liu;Qinqin Xia Dr.
Angewandte Chemie 2009 Volume 121( Issue 30) pp:5621-5624
Publication Date(Web):
DOI:10.1002/ange.200901850
Co-reporter:Ailing Liu, Xiaoming Zhang and Wanzhi Chen
Organometallics 2009 Volume 28(Issue 16) pp:4868-4871
Publication Date(Web):July 17, 2009
DOI:10.1021/om900419b
Pincer-like nickel complexes of N-heterocyclic carbenes, [Ni(3-chloro-1,4-di(N-aryl-N′-imidazolylidene)but-2-en-2-yl)(CH3CN)](PF6), have been prepared from the transmetalation reactions of the corresponding [Ag2(1,4-di(N-aryl-N′-imidazol-2-ylidene)but-2-yne)2](PF6)2 and [Ni(PPh3)2Cl2]. X-ray diffraction studies show that the distorted square-planar nickel(II) complexes are supported by anionic terdentate ligands with two imidazolylidenes and one vinyl carbon donor originated from chloronickelation of the triple bond. Further studies suggest that the nickel complexes are excellent catalysts for Kumada−Corriu coupling reactions of aryl chlorides even at room temperature.
Co-reporter:Yongbo Zhou, Wanzhi Chen and Daqi Wang
Dalton Transactions 2008 (Issue 11) pp:1444-1453
Publication Date(Web):23 Jan 2008
DOI:10.1039/B710916D
The mononuclear complexes [Ag(H2L1)(Py)2](NO3)·H2O (1, H2L1 = 2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine) and [Ag(NO3)(L2)] (2, L2 = 2,6-bis(5-methyl-1-isopropyl-1H-pyrazol-3-yl)pyridine), dinuclear complex [Ag2(H2L3)2(HL4)2] (3, H2L3 = 2,6-bis(5-phenyl-1H-pyrazol-3-yl)pyridine, HL4 = 6-(5-phenyl-1H-pyrazolyl-3-yl)picolinate), one-dimensional polymer {[Ag2(H2L1)2](NO3)2·H2O}n (4), and hexanuclear clusters [Ag6(HL1)4](X)2 (X = NO3−, 5; BF4−, 6; ClO4−, 7) stabilized by pincer-like bispyrazolyl ligands have been prepared and characterized using 1H NMR spectroscopy, elemental analysis, IR spectroscopy, luminescence spectroscopy and X-ray diffraction. In complex 3, there is a ligand unsupported Ag–Ag bond between the two silver atoms. Complex 4 displays a one-dimensional polymer consisting of an infinite Ag–Ag chain and every two adjacent silver ions are bridged by an H2L1 ligand. Complexes 5 and 7 have the same Ag6 cores in which six silver atoms are held together by four HL1 and five Ag–Ag bonds, while complex 6 was held together by six Ag–Ag bonds. The silver–silver distances in these complexes are found in the range of 2.874(1)–3.333(2) Å for ligand supported, and 3.040(1) Å for ligand unsupported Ag–Ag bonds, respectively. Complexes 3–7 are strongly luminescent due to either intraligand or metal–ligand charge transfer processes.
Co-reporter:Jiansheng Ye, Wanzhi Chen and Daqi Wang
Dalton Transactions 2008 (Issue 30) pp:4015-4022
Publication Date(Web):19 Jun 2008
DOI:10.1039/B801264D
[Pd(L1)2(CH3CN)](PF6)2 (L1 = 1-n-butyl-3-(2-pyrimidyl)imidazolylidene, 3) and [Pd(L2)2](PF6)2 (L2 = 1-(2-picolyl)-3-(2-pyrimidyl)imidazolylidene 4), prepared viacarbene transfer reactions of [Ag(L1)2]PF6 (1) and [Ag2(L2)2](PF6)2 (2) with palladium salts, respectively, have been fully characterized by 1H and 13C NMR spectroscopy and elemental analysis. The X-ray crystal structures of complexes 1–4 are reported. Complex 3 is an unusual pentacoordinated palladium complex, in which the palladium is coordinated by two imidazolylidene, two pyridine, and one acetonitrile molecule in a square-pyramidal geometry. The apical position is occupied by a pyrimidine nitrogen atom with a relatively long Pd–N distance (2.762(6) Å). Complex 4 is a typical square-planar palladium complex with palladium surrounded by two pairs of cis-arranged pyridine and imidazolylidene ligands. The complexes exhibit good catalytic activities in the Heck coupling reaction of aryl bromides and activated aryl chlorides under mild conditions.
Co-reporter:Jiansheng Ye, Shouwen Jin, Wanzhi Chen, Huayu Qiu
Inorganic Chemistry Communications 2008 Volume 11(Issue 4) pp:404-408
Publication Date(Web):April 2008
DOI:10.1016/j.inoche.2008.01.010
Reactions of the imidazolium salts with Ag2O afforded trinuclear silver complexes [Ag3(L)2(CH3CN)](PF6)3 (L = 2,7-bis(alkylimidazolylidenyl)naphthyridine), which have been characterized by NMR spectroscopy and X-ray diffraction analysis. The complexes consist of linearly arranged Ag3 cores showing weak silver–silver interactions as evidenced by the short silver–silver contacts (3.10–3.24 Å). The complexes are intensely emissive in their solid states.Two linearly arranged trinuclear silver complexes, [Ag3(L)2(CH3CN)](PF6)3 (L = 2,7-bis(alkylimidazolylidenyl)naphthyridine), have been characterized by NMR spectroscopy and X-ray diffraction analysis.
Co-reporter:Ailing Liu, Xiaoming Zhang, Wanzhi Chen, Huayu Qiu
Inorganic Chemistry Communications 2008 Volume 11(Issue 10) pp:1128-1131
Publication Date(Web):October 2008
DOI:10.1016/j.inoche.2008.06.015
Silver and gold complexes, [Ag2(L)2](PF6)2 and [Au2(L)2](PF6)2, supported by but-2-yne-1,4-diyl linked bis(N-heterocyclic carbene) ligand have been prepared and structurally characterized. The complexes display novel twisted macrocyclic conformation and weak intramolecular metal–metal interaction. The complexes are intensely emissive in their solid states.Macrocyclic silver and gold complexes, [Ag2(L)2](PF6)2 and [Au2(L)2](PF6)2 (L = 1,4-di(N-methylimidazolylidenyl)but-2-yne), have been prepared and structurally characterized.
Co-reporter:Jiansheng Ye ; Xiaoming Zhang ; Wanzhi Chen ;Shigeru Shimada
Organometallics 2008 Volume 27(Issue 16) pp:4166-4172
Publication Date(Web):July 24, 2008
DOI:10.1021/om800272k
Cleavage of a C−N bond of 3,6-(N-n-butylimidazolidenyl)pyridazine salt in its reactions with Ag2O and Pd(OAc)2 was observed. Subsequent palladation of the resultant N-n-butylimidazole resulted in the isolation of two novel dinuclear palladacyclic complexes. Both complexes consist of a Pd2C2N2 core with two palladium doubly bridged by anionic imidazoles in N,C5- or N,C2-coordination fashion. Accompanied with the C−N bond cleavage and palladation processes, addition of imidazole C−H to the C≡N bond of acetonitrile occurred in the reaction of Pd(OAc)2 and 3,6-(N-n-butylimidazolidenyl)pyridazine. All compounds have been fully characterized by the usual spectroscopic techniques, and their X-ray molecular structures are described. The two palladacyclic complexes show good catalytic activities in Heck−Mizoroki and Suzuki coupling reactions of activated aryl bromides.
Co-reporter:Yongbo Zhou, Zhenxing Xi, Wanzhi Chen and Daqi Wang
Organometallics 2008 Volume 27(Issue 22) pp:5911-5920
Publication Date(Web):October 20, 2008
DOI:10.1021/om800711g
[Ni2(3,5-bis(N-methylimidazolylidenylmethyl)pyrazolate)2](PF6)2 (1), [Ni2(μ-OH)(3,5-bis(N-pycolylimidazolylidenylmethyl)pyrazolate)](PF6)2 (2), and [Ni2(μ-OH)(3,5-bis(N-pyridylimidazolylidenylmethyl)pyrazolate)](PF6)2 (3) have been prepared from the corresponding imidazolium salts via in situ generated silver-carbene complexes. The complexes and imidazolium salts were characterized by elemental analyses and NMR spectroscopy. The structures of 1−3 were identified by X-ray diffraction analysis. In complex 1, two nickel(II) ions are sandwiched by two 3,5-bis(N-methylimidazolylidenylmethyl)pyrazolates behaving as anionic tetradentate ligands. Complexes 2 and 3 contain Ni2(μ-OH) cores with two nickel centers bridged by anionic hexadentate imidazolylidene ligands. Complexes 2 and 3 show excellent catalytic activities in Suzuki−Miyaura and Kumada−Corriu coupling reactions of various aryl chlorides. The cross-coupling reactions of deactivated aryl chlorides with arylboronic acids and Grignard reagents have been accomplished in excellent yields at low catalyst loadings.
Co-reporter:Xiaoming Zhang, Zhenxing Xi, Ailing Liu and Wanzhi Chen
Organometallics 2008 Volume 27(Issue 17) pp:4401-4406
Publication Date(Web):August 6, 2008
DOI:10.1021/om8003674
[Ag4(L)4](PF6)4 and [Pd(L)2](PF6)2 (L = 3-(2,4-dimethyl-1,8-naphthyrid-7-yl)-1-picolylimidazolylidene) have been prepared and fully characterized. The silver compound consists of a Ag4 ring with short Ag−Ag contacts displaying a butterfly conformation. The palladium complex exhibits a helical structure with palladium located in a square-planar environment with two carbene ligands and two pyridines in a cis arrangement. The palladium complex has proven to be a highly efficient catalyst for Heck coupling reactions of aryl bromides with n-butyl acrylate. TON values up to 106 and TOF values up to 5 × 105 h−1 can be achieved.
Co-reporter:Yongbo Zhou and Wanzhi Chen
Dalton Transactions 2007 (Issue 44) pp:5123-5125
Publication Date(Web):10 Oct 2007
DOI:10.1039/B712411B
Two novel, neutral, octanuclear copper(I) complexes displaying twisted-boat Cu8 conformations and short Cu–Cu interactions have been synthesized from hydrothermal reactions; the complexes show unusual multiple band emissions.
Co-reporter:Xiao-Ming ZHANG;Guo-Qiang WU;Wan-Zhi CHEN
Chinese Journal of Chemistry 2007 Volume 25(Issue 11) pp:1722-1727
Publication Date(Web):13 NOV 2007
DOI:10.1002/cjoc.200790318
A convenient and practical route to functionalized conjugated 1,3-enynes and 1,3-dienes is described. 1,4-Bis(heteroaryl)-1,3-diene and 1-heteroarylbut-1-en-3-yne derivatives were prepared from 1,4-dichloro-2-butyne and corresponding N-heteroarenes such as imidazole, pyrrole, pyrazole and indole derivatives in the presence of bases in good to high yields.
Co-reporter:Shouwen Jin;Daqi Wang
Journal of Inorganic and Organometallic Polymers and Materials 2007 Volume 17( Issue 4) pp:583-588
Publication Date(Web):2007 December
DOI:10.1007/s10904-007-9148-x
[Co2(L1)2(NCS)4]·4MeOH 1, [Co(L2)2(H2O)2](Sal)2·4H2O (Sal = salicylate) 2 were obtained from self-assembly of the cobalt salts with bis(N-benzimidazolyl)methane (L1), and bis(N-benzimidazolyl)methane (L2), and their structures were characterized by IR and X-ray diffraction analysis. Complex 1 exhibits a two-dimensional grid structure, whereas complex 2 is a coordination polymer having a one-dimensional linear chain structure. The grid in 1 lies parallel to the crystallographic ab plane and exhibits intra-grid M–M separations of 10.508 × 10.508 Å. Hydrogen bonds hold the cationic chains in 2 together leading to a three-dimensional network structure.
Co-reporter:Zhenxing Xi, Xiaoming Zhang, Wanzhi Chen, Shizhou Fu and Daqi Wang
Organometallics 2007 Volume 26(Issue 26) pp:6636-6642
Publication Date(Web):November 20, 2007
DOI:10.1021/om700796g
The imidazolium salts bis(N-pyridylimidazoliumyl)methane hexafluorophosphate ([H2L1](PF6)2) and bis(N-picolyl)benzimidazoliumyl)methane hexafluorophosphate ([H2L2](PF6)2) as the precursors of potentially tetradentate NHC ligands were synthesized in 63–98% yields. Their reactions with Ag2O afforded silver−NHC complexes [Ag3(L1)2(CH3CN)2](PF6)3 (1) and [Ag4(L2)2(CH3CN)2](PF6)4 (2), respectively. Further reactions of these silver complexes as carbene transfer reagents yielded square-planar nickel(II) complexes [NiL1](PF6)2 (3) and [NiL2](PF6)2 (4), respectively. These silver and nickel complexes have been fully characterized by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. Both 3 and 4 catalyzed Suzuki-type cross-coupling of aryl chlorides and bromides containing electron-withdrawing and electron-donating substituents. Complex 3 is a more active catalyst under mild conditions.
Co-reporter:Fenghui Liu, Wanzhi Chen and Daqi Wang
Dalton Transactions 2006 (Issue 24) pp:3015-3024
Publication Date(Web):10 Mar 2006
DOI:10.1039/B514757C
Seven Pt–Ag coordination polymers [Pt(NH3)2(NHCOtBu)2Ag(H2O)](ClO4) (1), [Pt2(dap)2(NHCOtBu)4Ag2(NO3)(ClO4)] (dap = 1,2-diaminopropane, 2), [Pt2(en)2(NHCOtBu)4Ag2(m-C6H4(CO2)2)]·3H2O (en = ethylenediamine, 3), [Pt2(NH3)2(NHCOtBu)2Ag2(p-C6H4(CO2)2)]·2H2O (4), [Pt3(en)3(NHCOtBu)6Ag2(p-C6H4(CO2)2)1.5]·6H2O (5), [Pt(NH3)2(NHCOtBu)4Ag(4-C5H4NCO2)2]·10H2O (6), and [Pt2(en)2(NHCOtBu)4Ag2(4-C5H4NCO2)](ClO4) (7) were synthesized from the corresponding [Pt(RNH2)2(NHCOtBu)2] and Ag salts, respectively, and their structures were determined by X-ray crystallography. The Pt and Ag units aggregate into one-dimensional chains based on Pt–Ag backbones. Compounds 1, 2, and 6 possess an extended zigzag Pt–Ag chain motif, and the metallic chains arrange in a parallel fashion into layered structures. Compounds 3–5, and 7 form 2-D brick wall sheets due to the coordination of the bifunctional anions to the Ag+ ions of the neighboring chains. These polymers are constructed based on the Pt–Ag interactions and the coordination of amidate oxygen atoms to Ag ions. There are three kinds of short Pt–Ag bonds observed in the structures of these compounds. The Pt–Ag metallic backbone is formed by the stacking unsupported Pt–Ag bonds, the amidate doubly bridged Pt–Ag bonds, and the amidate singly bridged Pt–Ag bonds. In the chains, the Pt–Ag bond distances are quite short, and appear in the range of 2.78–2.97 Å, which are comparable to known Pt–Ag dative bonds.
Co-reporter:Fenghui Liu, Wanzhi Chen and Daqi Wang
Dalton Transactions 2006 (Issue 28) pp:3445-3453
Publication Date(Web):26 Apr 2006
DOI:10.1039/B516410A
A number of pivalamidate bridged dinuclear [PtII2(RNH2)4(NHCOtBu)2]2+, [PtIII2LL′ (RNH2)4(NHCOtBu)2]n+ (2RNH2 = 2NH3, 1,2-ethylenediamine, 1,2-diaminocyclohexane; L, L′ = NO3−, H2O, or ketonate), trinuclear [{PtII(dap)(NHCOtBu)2}2PdIII]3+ (dap = 1,2-diaminopropane), tetranuclear [{PtII2(NH3)2(DACH)(NHCOtBu)2}2]4+ (DACH = 1,2-diaminocyclohexane), pentanuclear [{Pt2(C5H7O)(NH3)2Cl2(NHCOtBu)2}2PtCl4], and hexanuclear [Pt2(NH3)2(en)(NHCOtBu)2Pt(NO2)4]2 platinum complexes containing Pt(II)–Pt(II), Pt(II)–Pt(III), Pt(II)–Pd(III), and Pt(III)–Pt(III) interactions have been prepared and structurally characterized. The Pt–Pt interactions are characteristic of covalent, dative, or orbital symmetric Pt–Pt bonds. The dimeric Pt(III) complexes are able to activate C–H bonds of ketones to afford ketonate platinum(III) complexes. The Pt–Pt bonds are either doubly amidate-bridged or ligand unsupported. Their distances are 2.99–3.22 Å for Pt(II)–Pt(II), 2.59–2.72 Å for Pt(III)–Pt(III), 2.98 Å for Pt(II)–Pt(III), and 2.66 Å for Pt(II)–Pd(III) bonds depending on the oxidation states of the two metals and the ancillary ligands.
Co-reporter:Fenghui Liu
European Journal of Inorganic Chemistry 2006 Volume 2006(Issue 6) pp:
Publication Date(Web):2 FEB 2006
DOI:10.1002/ejic.200500878
New bis(amidate)platinum(II) complexes with the general formula cis-[Pt(RNH2)2(NHCOtBu)2] were prepared by the hydrolysis of the corresponding cis-[Pt(RNH2)2(tBuCN)2]2+ complex. The bis(amidate)platinum(IV) complexes with the formula trans,cis,cis-[PtCl2(RNH2)2(NHCOtBu)2] (5: R = H, 6: R = Et), trans,cis,cis-[PtCl(OH)(RNH2)2(NHCOtBu)2] (8: R = H, 9: R = Et, and 10: 2 R = 1,2-cHex), and mono(amidate) complex mer-[PtCl3(DACH)(NHCOtBu)2] (7, DACH = trans-1,2-diaminocyclohexane) have been generated selectively by the oxidative addition of Cl2 and HClO to the corresponding platinum(II) complexes, [Pt(RNH2)2(NHCOtBu)2], in water. All the prepared compounds were characterized byelemental analyses and 1H and 195Pt NMR spectroscopy.The structures of trans,cis,cis-[PtCl2(NH3)2(NHCOtBu)2] (5), trans,cis,cis-[PtCl2(EtNH2)2(NHCOtBu)2] (6), mer-[PtCl3(DACH)(NHCOtBu)] (7), and trans,cis,cis-[PtCl(OH)(DACH)(NHCOtBu)2] (10) have been confirmed by X-ray diffraction analyses. The structures of these platinum(IV) complexes adopt an octahedral geometry. The Pt–N, Pt–O, and Pt–Cl distances are in the expected ranges. These complexes are rare examples of bis(amidate)- and mono(amidate)platinum(IV) complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Co-reporter:Jiansheng Ye, Wanzhi Chen and Daqi Wang
Dalton Transactions 2008(Issue 30) pp:NaN4022-4022
Publication Date(Web):2008/06/19
DOI:10.1039/B801264D
[Pd(L1)2(CH3CN)](PF6)2 (L1 = 1-n-butyl-3-(2-pyrimidyl)imidazolylidene, 3) and [Pd(L2)2](PF6)2 (L2 = 1-(2-picolyl)-3-(2-pyrimidyl)imidazolylidene 4), prepared viacarbene transfer reactions of [Ag(L1)2]PF6 (1) and [Ag2(L2)2](PF6)2 (2) with palladium salts, respectively, have been fully characterized by 1H and 13C NMR spectroscopy and elemental analysis. The X-ray crystal structures of complexes 1–4 are reported. Complex 3 is an unusual pentacoordinated palladium complex, in which the palladium is coordinated by two imidazolylidene, two pyridine, and one acetonitrile molecule in a square-pyramidal geometry. The apical position is occupied by a pyrimidine nitrogen atom with a relatively long Pd–N distance (2.762(6) Å). Complex 4 is a typical square-planar palladium complex with palladium surrounded by two pairs of cis-arranged pyridine and imidazolylidene ligands. The complexes exhibit good catalytic activities in the Heck coupling reaction of aryl bromides and activated aryl chlorides under mild conditions.
Co-reporter:Xiaoming Zhang, Qinqin Xia and Wanzhi Chen
Dalton Transactions 2009(Issue 35) pp:NaN7054-7054
Publication Date(Web):2009/06/29
DOI:10.1039/B903285A
Palladium complexes, [Pd(1-butyl-3-((7-methyl-1,8-naphthyridin-2-yl)methyl)imidazolylidene)2](PF6)2 (1), [Pd(3-methyl-1-(pyrimidin-2-yl)imidazolylidene)2(CH3CN)](PF6)2 (4), [Pd(3-benzyl-1-(pyrimidin-2-yl)imidazolylidene)2(CH3CN)](PF6)2 (5), [Pd(3-ethyl-1-(pyrimidin-2-yl)imidazolylidene)2Cl](PF6) (6), and [Pd(3-benzyl-1-(pyrimidin-2-yl)imidazolylidene)Cl2] (7), have been prepared viatransmetallation of corresponding in situ generated silver-carbene complexes. These palladium complexes have been characterized by NMR spectroscopy and elemental analyses, and their structures were determined by X-ray single-crystal diffraction. Complexes 1 and 7 are tetracoordinate displaying square-planar geometry. Complexes 4–6 are pentacoordinate showing uncommon square-pyramidal geometry with acetonitrile or chloride at the equatorial position. The Suzuki and Hiyama coupling reactions of a wide range of aryl bromides and chlorides have been comparatively investigated by using tetracoordinate moncarbene, tetracoordinate dicarbene, and pentacoordinate dicarbene palladium complexes as catalysts. The tetracoordinate moncarbene palladium complex showed the highest catalytic activity for both coupling reactions.
Co-reporter:Zhenxing Xi, Bin Liu, Chunxin Lu and Wanzhi Chen
Dalton Transactions 2009(Issue 35) pp:NaN7014-7014
Publication Date(Web):2009/07/06
DOI:10.1039/B906242D
Cobalt(III) complexes, [CoCl2(L1)2](PF6) (1, L1 = N-methyl-N-(2-pyrimidinyl)imidazolylidene), [CoCl(L2)2](PF6)2 (2, L2 = N-picolyl-(2-pyrimidinyl)imidazolylidene), [Co(L3)2](PF6)3 (3, L3 = bis(N-2-pyrimidylimidazolylidenyl)methane) and [CoCl2(L3)](PF6) (4) have been prepared from the corresponding pyrimidine functionalized imidazolium salts [HL1](PF6), [HL2](PF6), and [H2L3](PF6)2via in situ generated silver carbene complexes under mild conditions. These cobalt complexes were characterized by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. The cobalt complexes have been found to be good catalyst precursors for Kumada–Corriu cross-coupling reactions of aryl halides and Grignard reagents at room temperature. Complex 1 is more active under the mild conditions.
Co-reporter:Chunxin Lu, Shaojin Gu, Wanzhi Chen and Huayu Qiu
Dalton Transactions 2010 - vol. 39(Issue 17) pp:NaN4204-4204
Publication Date(Web):2010/03/24
DOI:10.1039/B924587A
The platinum(II) complexes of multidentate N-heterocyclic carbenes, [Pt(L1)2Cl](PF6) (1, L1 = N-methyl-N-(2-pyrimidinyl)imidazolylidene), [Pt(L2)Cl](PF6) (2, L2 = N-butyl-N-(1,10-phenanthrolin-2-yl)imidazolylidene), [PtL3](PF6)2 (3, L3 = bis(N-picolylimidazolylidenyl)methane), [PtL4](PF6)2 (4, L4 = (bis(N-2-pyrimidylimidazolylidenyl)methane) (4) and [Pt(L5)2](PF6)2 [5, L5 = bis(N-pyridylimidazoliumyl)methane] have been synthesized and structurally characterized. All these complexes exhibit slightly distorted square-planar configuration. These complexes are efficient catalyst precursors for hydrosilylation of alkynes. Complexes 2 and 4 are much more active than complexes 1, 3 and 5. In the hydrosilylation of arylacetylenes, relatively long induction periods were observed for 1, 3 and 5.
Co-reporter:Chao Chen, Wanzhi Chen and Huayu Qiu
Dalton Transactions 2012 - vol. 41(Issue 43) pp:NaN13412-13412
Publication Date(Web):2012/09/04
DOI:10.1039/C2DT31739G
The reaction of neutral palladium complexes PdLBr2 (L = 1,1′-di(alkyl)-3,3′-methylenediimidazolin-2,2′-diylidene) with NH4PF6 in CH3CN afforded [PdL(NH3)2](PF6)2 (1–3, L1, alkyl = Me; L2, alkyl = Et; L3, alkyl = iso-Pr) and [PdL4(CH3CN)2](PF6)2 (4, alkyl = Mes). Treatment of [PdL(NH3)2](PF6)2 complexes with N-donors, 9-ethyl-3,6-diimidazolyl-carbazole (dicz), mercaptopyridine (HSPy), 3,5-dimethyl-1H-pyrazole (Hdmpz), and 1,2-dibenzoylhydrazine (H2dbhz) resulted in the substitution of NH3 forming dinuclear palladium complexes [PdL1(dicz)]2(PF6)4 (5), [PdL1(SPy)]2(PF6)2 (6), [PdL2(dmpz)]2(PF6)2 (7), [(PdL2)2(dbhz)] (8). Reaction of [PdL2(NH3)2](PF6)2 with hydrazine led to a mixture of [Pd(L2)2](PF6)2 (9) and [PdL2(NH2NC(CH3)NHNH2)](PF6)2 (10). The NH2NC(CH3)NHNH2 moiety was formed in situ by nucleophilic addition to CH3CN by two molecules of NH2NH2 and subsequent NH3 elimination. All of these complexes have been fully characterized by ESI-MS, NMR spectroscopy, and elemental analysis. The molecular structures of 1 and 5–10 were also studied by X-ray diffraction analysis.
Co-reporter:Xiaolong Liu and Wanzhi Chen
Dalton Transactions 2012 - vol. 41(Issue 2) pp:NaN608-608
Publication Date(Web):2011/11/03
DOI:10.1039/C1DT11356A
A family of hexa-coordinated ruthenium(II) complexes of bis(N-pyridylimidazolylidenyl)methane (L) were prepared and structurally characterized. Carbene transfer reactions of [Ru(p-cymene)Cl2]2, [Ru(CO)2Cl2]n and RuHCl(CO)(PPh3)3 with silver–NHC complexes in situ generated from [H2L](PF6)2 and Ag2O afforded [RuL(CH3CN)2](PF6)2 (1), [Ru2L(p-cymene)2Cl2](PF6)2 (2), [RuL(CO)2](PF6)2 (3) and [RuL(PPh3)2](PF6)2 (4), respectively. The reactions of 1 towards several N- and P-donors were studied. The treatment of 1 with 1,10-phenanthroline resulted in the substitution of one pyridine and one acetonitrile molecule affording [RuL(phen)(CH3CN)](PF6)2 (5) as a mixture of two isomers. Reaction of 1,2-bis(diphenylphosphino)ethane (dppe) and 1 gave [RuL(dppe)(CH3CN)2](PF6)2 (7), in which two pyridines were substituted by a dppe ligand trans to two NHC groups. In contrast, reactions of 1 with ethane-1,2-diamine, propane-1,3-diamine and 3,5-dimethyl-1H-pyrazole led to the substitution of acetonitrile and subsequent N–H addition of the CN bond of the coordinated acetonitrile yielding [RuL(ethane-1,2-diamine)(N-(2-aminoethyl)acetimidamide)](PF6)2 (8), [RuL(propane-1,3-diamine)(N-(3-aminopropyl)acetimidamide)](PF6)2 (9) and RuL(1-(3,5-dimethyl-1H-pyrazol-1-yl)ethanimine)(CH3CN)](PF6)2 (10), respectively.
Co-reporter:Yongbo Zhou and Wanzhi Chen
Dalton Transactions 2007(Issue 44) pp:
Publication Date(Web):
DOI:10.1039/B712411B
Co-reporter:Shaojin Gu, Jiehao Du, Jingjing Huang, Yun Guo, Ling Yang, Weilin Xu and Wanzhi Chen
Dalton Transactions 2017 - vol. 46(Issue 2) pp:NaN594-594
Publication Date(Web):2016/12/08
DOI:10.1039/C6DT03944H
This report describes the synthesis and characterization of a family of unsymmetrical NCN pincer Ni(II) complexes 2–8 with NHC-triazole arms. All of these complexes have been fully characterized by X-ray single crystal analysis, NMR spectroscopy, and elemental analysis. Complexes 2 and 4–6 were square planar with a chloride trans to the carbene carbon atoms. Complex 3 was a paramagnetic octahedral complex with its central metal surrounded by two NCN pincer ligands. Complexes 7 and 8 contain [(NHC)2Ni2-OH] moieties bearing a OH bridge. Both the [(NHC)2Ni2-OH] complexes 7 and 8 and [(NCNHCN)Ni-Cl] complexes 2 and 4–6 were synthesized similarly via the reactions of the in situ formed Ag–NHCs from the corresponding imidazolium salts with [NiCl2(PPh3)2]. The catalytic activities of all complexes for Suzuki–Miyaura cross-coupling were examined. Under the optimized conditions, complex 4 was active in the Suzuki–Miyaura cross-coupling reactions of aryl iodides and aryl bromides at 110 °C. Aryl chlorides were successfully coupled in the presence of triphenylphosphine as an additive.
Co-reporter:Xueji Ma, Feifei Wu, Xiaofei Yi, Hangxiang Wang and Wanzhi Chen
Chemical Communications 2015 - vol. 51(Issue 31) pp:NaN6865-6865
Publication Date(Web):2015/03/13
DOI:10.1039/C5CC01271F
Intramolecular sp3 C–H insertion reaction of α-imino rhodium carbene generated from N-sulfonyl-1,2,3-triazoles has been described. A number of 2,3-dihydrobenzofuran and benzofuran derivatives have been obtained in good to excellent yields.
Co-reporter:Bin Liu, Yin Zhang, Daichao Xu and Wanzhi Chen
Chemical Communications 2011 - vol. 47(Issue 10) pp:NaN2885-2885
Publication Date(Web):2011/01/18
DOI:10.1039/C0CC05260D
A novel electrochemical procedure for the preparation of metal complexes of N-heterocyclic carbenes using imidazolium salts or corresponding silver–NHC complexes as carbene sources and electrolytes, and metal plates as the sacrificial anodes is described. The procedure is simple and good yielding without the use of expensive or air-sensitive reagents.
Co-reporter:Bo Liu, Xueji Ma, Feifei Wu and Wanzhi Chen
Dalton Transactions 2015 - vol. 44(Issue 4) pp:NaN1844-1844
Publication Date(Web):2014/11/27
DOI:10.1039/C4DT02986K
A direct and practical synthetic route to N-heterocyclic carbene copper complexes of [(NHC)CuX] (X = halide) and [(NHC)2Cu]PF6 types using commercially available copper powder is described. A number of copper-NHC complexes have been obtained in a range of yields from 26 to 99%. The reactions take place in air without removal of moisture and oxygen, and the excess of copper powder can be easily removed via simple filtration after completion. The direct reactions of imidazolium salts and copper powder can also be performed in aqueous media avoiding tedious purification processes. The procedure is also suitable for gram-scale preparation.
Co-reporter:Shaojin Gu, Bo Liu, Jiuxi Chen, Huayue Wu and Wanzhi Chen
Dalton Transactions 2012 - vol. 41(Issue 3) pp:NaN970-970
Publication Date(Web):2011/11/17
DOI:10.1039/C1DT11269D
Mononuclear ruthenium complexes [RuCl(L1)(CH3CN)2](PF6) (2a), [RuCl(L2)(CH3CN)2](PF6) (2b), [Ru(L1)(CH3CN)3](PF6)2 (4a), [Ru(L2)(CH3CN)3](PF6)2 (4b), [Ru(L2)2](PF6)2 (5), [RuCl(L1)(CH3CN)(PPh3)](PF6) (6), [RuCl(L1)(CO)2](PF6) (7), and [RuCl(L1)(CO)(PPh3)](PF6) (8), and a tetranuclear complex [Ru2Ag2Cl2(L1)2(CH3CN)6](PF6)4 (3) containing 3-(1,10-phenanthrolin-2-yl)-1-(pyridin-2-ylmethyl)imidazolylidene (L1) and 3-butyl-1-(1,10-phenanthrolin-2-yl)imidazolylidene (L2) have been prepared and fully characterized by NMR, ESI-MS, UV-vis spectroscopy, and X-ray crystallography. Both L1 and L2 act as pincer NNC donors coordinated to ruthenium (II) ion. In 3, the Ru(II) and Ag(I) ions are linked by two bridging Cl− through a rhomboid Ag2Cl2 ring with two Ru(II) extending to above and down the plane. Complexes 2–8 show absorption maximum over the 354–428 nm blueshifted compared to Ru(bpy)32+ due to strong σ-donating and weak π-acceptor properties of NHC ligands. Electrochemical studies show Ru(II)/Ru(III) couples over 0.578–1.274 V.
Co-reporter:Shaojin Gu, Daichao Xu and Wanzhi Chen
Dalton Transactions 2011 - vol. 40(Issue 7) pp:NaN1583-1583
Publication Date(Web):2011/01/07
DOI:10.1039/C0DT01211D
Mono- and polynuclear complexes containing 3-(1,10-phenanthrolin-2-yl)-1-(pyridin-2-ylmethyl)imidazolylidene (L), [NiL2](PF6)2 (2), [CoL2](PF6)3 (3), [PtLCl](PF6) (4), [PdAgL2](PF6)3 (5), [PdCuL2](PF6)3 (6), [Pd2L2Cl2](PF6)2 (7), and [Pd3L2Cl4](PF6)2 (8) have been prepared and fully characterized by NMR, ESI-MS spectroscopy, and X-ray crystallography. In complexes 2–4, the ligand binds to metals in a pincer NNC fashion with the pyridine group uncoordinated. Complexes 5 and 6 are isostructural to each other in which the palladium ions are surrounded by two pyridines and two imidazolylidenes and Ag(I) or Cu(I) is coordinated by two 1,10-phenanthroline moieties. In the trinuclear palladium complex 8, one palladium ion has an identical coordination mode as in 5 and 6, and the other two palladium ions are bonded to the 1,10-phenanthroline. Complex 6 exhibits excellent catalytic activity for the tandem click/Sonogashira reaction of 1-(bromomethyl)-4-iodobenzene, NaN3, and ethynylbenzene in which three C–N bonds and one C–C bond are formed in a single flask.
Co-reporter:Yongbo Zhou, Wanzhi Chen and Daqi Wang
Dalton Transactions 2008(Issue 11) pp:NaN1453-1453
Publication Date(Web):2008/01/23
DOI:10.1039/B710916D
The mononuclear complexes [Ag(H2L1)(Py)2](NO3)·H2O (1, H2L1 = 2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine) and [Ag(NO3)(L2)] (2, L2 = 2,6-bis(5-methyl-1-isopropyl-1H-pyrazol-3-yl)pyridine), dinuclear complex [Ag2(H2L3)2(HL4)2] (3, H2L3 = 2,6-bis(5-phenyl-1H-pyrazol-3-yl)pyridine, HL4 = 6-(5-phenyl-1H-pyrazolyl-3-yl)picolinate), one-dimensional polymer {[Ag2(H2L1)2](NO3)2·H2O}n (4), and hexanuclear clusters [Ag6(HL1)4](X)2 (X = NO3−, 5; BF4−, 6; ClO4−, 7) stabilized by pincer-like bispyrazolyl ligands have been prepared and characterized using 1H NMR spectroscopy, elemental analysis, IR spectroscopy, luminescence spectroscopy and X-ray diffraction. In complex 3, there is a ligand unsupported Ag–Ag bond between the two silver atoms. Complex 4 displays a one-dimensional polymer consisting of an infinite Ag–Ag chain and every two adjacent silver ions are bridged by an H2L1 ligand. Complexes 5 and 7 have the same Ag6 cores in which six silver atoms are held together by four HL1 and five Ag–Ag bonds, while complex 6 was held together by six Ag–Ag bonds. The silver–silver distances in these complexes are found in the range of 2.874(1)–3.333(2) Å for ligand supported, and 3.040(1) Å for ligand unsupported Ag–Ag bonds, respectively. Complexes 3–7 are strongly luminescent due to either intraligand or metal–ligand charge transfer processes.
Co-reporter:Shixian Zhao, Feifei Wu, Yuyu Ma, Wanzhi Chen, Miaochang Liu and Huayue Wu
Organic & Biomolecular Chemistry 2016 - vol. 14(Issue 8) pp:NaN2555-2555
Publication Date(Web):2016/01/22
DOI:10.1039/C5OB02397A
A few rhodium complexes of N-heterocyclic carbenes were prepared through carbene transfer reactions and their structures were characterized by X-ray diffraction analysis. The rhodium complexes of NHCs are found to be efficient catalysts for vinylation of various triazoles via C–H activation. A number of double vinylated triazoles can be obtained in good yields.
![Copper, [1,3-bis[2,6-bis(1-methylethyl)phenyl]-1,3-dihydro-2H-imidazol-2-ylidene]iodo-](/data/chemimg/125800/950206-91-4.png)
![Copper, [1,3-bis[2,6-bis(1-methylethyl)phenyl]-1,3-dihydro-2H-imidazol-2-ylidene]iodo-](/data/chemimg/125800/950206-91-4_b.png)
![1,3-Dioxolane, 2-[(1E)-2-(4-methylphenyl)ethenyl]-](http://img.cochemist.com/ccimg/916600/916576-31-3.png)
![1,3-Dioxolane, 2-[(1E)-2-(4-methylphenyl)ethenyl]-](http://img.cochemist.com/ccimg/916600/916576-31-3_b.png)
![Copper, [1,3-bis[2,6-bis(1-methylethyl)phenyl]-2-imidazolidinylidene]chloro-](/data/chemimg/123800/915395-52-7.png)
![Copper, [1,3-bis[2,6-bis(1-methylethyl)phenyl]-2-imidazolidinylidene]chloro-](/data/chemimg/123800/915395-52-7_b.png)
![Copper, [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]chloro-](http://img.cochemist.com/ccimg/855600/855517-60-1.png)
![Copper, [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]chloro-](http://img.cochemist.com/ccimg/855600/855517-60-1_b.png)
![1,3-DIOXOLANE, 2-[(1E)-2-(4-CHLOROPHENYL)ETHENYL]-](http://img.cochemist.com/ccimg/592600/592510-50-4.png)
![1,3-DIOXOLANE, 2-[(1E)-2-(4-CHLOROPHENYL)ETHENYL]-](http://img.cochemist.com/ccimg/592600/592510-50-4_b.png)
![Furan, tetrahydro-2-[(1E)-2-(2-naphthalenyl)ethenyl]-](http://img.cochemist.com/ccimg/592600/592510-29-7.png)
![Furan, tetrahydro-2-[(1E)-2-(2-naphthalenyl)ethenyl]-](http://img.cochemist.com/ccimg/592600/592510-29-7_b.png)
![FURAN, 2-[(1E)-2-(4-FLUOROPHENYL)ETHENYL]TETRAHYDRO-](http://img.cochemist.com/ccimg/592600/592510-28-6.png)
![FURAN, 2-[(1E)-2-(4-FLUOROPHENYL)ETHENYL]TETRAHYDRO-](http://img.cochemist.com/ccimg/592600/592510-28-6_b.png)
![Furan, 2-[(1E)-2-(2-fluorophenyl)ethenyl]tetrahydro-](http://img.cochemist.com/ccimg/592600/592510-27-5.png)
![Furan, 2-[(1E)-2-(2-fluorophenyl)ethenyl]tetrahydro-](http://img.cochemist.com/ccimg/592600/592510-27-5_b.png)
![FURAN, 2-[(1E)-2-(4-CHLOROPHENYL)ETHENYL]TETRAHYDRO-](http://img.cochemist.com/ccimg/592600/592510-26-4.png)
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