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1.
Alexander J. Blake Pamela V. Mason Claire Wilson Neil R. Champness 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(6):m280-m282
The single‐crystal X‐ray structures of dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylate, C14H12N2O4, and the copper(I) coordination complex bis(dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylato‐κ2N,N′)copper(I) tetrafluoroborate, [Cu(C14H12N2O4)2]BF4, are reported. The uncoordinated ligand crystallizes across an inversion centre and adopts the anticipated anti pyridyl arrangement with coplanar pyridyl rings. In contrast, upon coordination of copper(I), the ligand adopts an arrangement of pyridyl donors facilitating chelating metal coordination and an increased inter‐pyridyl twisting within each ligand. The distortion of each ligand contrasts with comparable copper(I) complexes of unfunctionalized 2,2′‐bipyridine. 相似文献
2.
Paweł Czerwiński Edyta Molga Prof. Luigi Cavallo Dr. Albert Poater Dr. Michał Michalak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8089-8094
An efficient and easily scalable NHC–copper(I) halide‐catalyzed addition of terminal alkynes to 1,1,1‐trifluoromethyl ketones, carried out on water for the first time, is reported. A series of addition reactions were performed with as little as 0.1–2.0 mol % of [(NHC)CuX] (X=Cl, Br, I, OAc, OTf) complexes, providing tertiary propargylic trifluoromethyl alcohols in high yields and with excellent chemoselectivity from a broad range of aryl‐ and more challenging alkyl‐substituted trifluoromethyl ketones (TFMKs). DFT calculations were performed to rationalize the correlation between the yield of catalytic alkynylation and the sterics of N‐heterocyclic carbenes (NHCs), expressed as buried volume (%VBur), indicating that steric effects dominate the yield of the reaction. Additional DFT calculations shed some light on the differential reactivity of [(NHC)CuX] complexes in the alkynylation of TFMKs. The first enantioselective version of a direct alkynylation in the presence of C1‐symmetric NHC–copper(I) complexes is also presented. 相似文献
3.
Dr. Yuh Kohyama Dr. Takashi Murase Prof. Dr. Makoto Fujita 《Angewandte Chemie (International ed. in English)》2014,53(43):11510-11513
The discrete cavity of a self‐assembled palladium–tris(4‐pyridyl)triazine cage dictates the ratio of metal, ligand, and a non‐coordinative molecule in the formation of silver(I)–dialkyl chalcogenide (Et, nBu; S, Se) complexes and defines their coordination arrangement. 相似文献
4.
Reaction of copper halides CuX (X=Cl, Br, I) with tri(2‐pyridylmethyl)amine) (TPMA) in THF under N2 affords a series of monomeric copper(I) complexes CuX(TPMA) (X=Cl ( 1 ), Br ( 2 ) and I ( 3 )). Treatment of [CuCl(TPMA)] ( 1 ) with 0.5 equivalent of 1,4‐diisocyanobenzene following by equimolar amount of NaBF4 affords a novel binuclear complex [(TPMA)Cu(μ‐1,4‐CNC6H4NC)Cu(TPMA)](BF4)2 ( 4 ). The copper(I) halide TPMA complexes show interesting fluxional behaviors in temperature dependence in the 1H NMR spectrum that can be explained by the dissociation and reassociation of the pyridyl group and alkylamine nitrogen of TPMA ligand. The crystal structures of 1 , 3 and 4 are determined by an X‐ray diffractometer. Complexes 1 and 3 are distorted tetrahedral coordinates with strong bonding between three pyridyl N atoms and the corresponding halide donor. Crystallographic results of 4 clearly indicates two Cu(I) ions are bridged by 1,4‐diisocyanobenzene, forming a centro‐symmetrical homobinuclear complex with a “dangling” uncoordinated pyridyl group. 相似文献
5.
PENG Jiajian CHEN Lingzhen XU Zheng HU Yingqian LI Jiayun BAI Ying QIU Huayu LAI Guoqiao 《中国化学》2009,27(11):2121-2124
By using functionalized imidazolium salts such as 1‐allyl‐3‐alkylimidazolium or 1‐alkyl‐3‐vinylimidazolium salts as carbene ligand precursors, the reduction of aryl ketones with triethoxysilane may be catalyzed by copper salt/imidazolium salt/KOtBu systems. The functional substituents attached to the N‐heterocyclic carbene (NHC) serve to enhance the catalytic activity. Different copper salts also have an effect on the catalytic activity, with copper(II) acetate monohydrate being superior to copper(I) chloride. 相似文献
6.
Copper and silver N‐heterocyclic carbene (NHC) complexes were prepared through a simple, base‐free protocol involving the decomposition of corresponding imidazol(in)ium‐2‐carboxylates under thermolytic conditions and a subsequent reaction of the in situ generated carbenes with copper(I) or silver(I) chloride, respectively. The desired NHC metal complexes were isolated with good yields after simple crystallization. 相似文献
7.
Christian H. G. Jakob Bruno Dominelli Julia Rieb Christian Jandl Alexander Pthig Robert M. Reich Joo D. G. Correia Fritz E. Kühn 《化学:亚洲杂志》2020,15(12):1848-1851
A novel N,N’‐allyl‐bridged bisimidazolium salt and a novel dinuclear Ag(I) and a Au(I) NHC complex are reported. Both metallacyclic complexes have a twisted structural shape due to the rigid allylic system and form two different isomers relating to the position of the double bonds. The allyl‐group shows photoisomerisation, but no reactivity towards bases for the additional coordination of Pd(II). 相似文献
8.
Bobby Happ Dr. Georges M. Pavlov Esra Altuntas Christian Friebe Dr. Martin D. Hager Dr. Andreas Winter Dr. Helmar Görls Dr. Wolfgang Günther Prof. Dr. Ulrich S. Schubert 《化学:亚洲杂志》2011,6(3):873-880
Two 3,6‐bis(R‐1H‐1,2,3‐triazol‐4‐yl)pyridazines (R=mesityl, monodisperse (CH2 CH2O)12CH3) were synthesized by the copper(I)‐catalyzed azide–alkyne cycloaddition and self‐assembled with tetrakis(acetonitrile)copper(I) hexafluorophosphate and silver(I) hexafluoroantimonate in dichloromethane. The obtained copper(I) complexes were characterized in detail by time‐dependent 1D [1H, 13C] and 2D [1H‐NOESY] NMR spectroscopy, elemental analysis, high‐resolution ESI‐TOF mass spectrometry, and analytical ultracentrifugation. The latter characterization methods, as well as the comparison to analog 3,6‐di(2‐pyridyl)pyridazine (dppn) systems and their corresponding copper(I) and silver(I) complexes indicated that the herein described 3,6‐bis(1H‐1,2,3‐triazol‐4‐yl)pyridazine ligands form [2×2] supramolecular grids. However, in the case of the 3,6‐bis(1‐mesityl‐1H‐1,2,3‐triazol‐4‐yl)pyridazine ligand, the resultant red‐colored copper(I) complex turned out to be metastable in an acetone solution. This behavior in solution was studied by NMR spectroscopy, and it led to the conclusion that the copper(I) complex transforms irreversibly into at least one different metal complex species. 相似文献
9.
Elevated Catalytic Activity of Ruthenium(II)–Porphyrin‐Catalyzed Carbene/Nitrene Transfer and Insertion Reactions with N‐Heterocyclic Carbene Ligands
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Ka‐Ho Chan Dr. Xiangguo Guan Dr. Vanessa Kar‐Yan Lo Prof. Dr. Chi‐Ming Che 《Angewandte Chemie (International ed. in English)》2014,53(11):2982-2987
Bis(NHC)ruthenium(II)–porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans M?CRR′/M?NR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene C? H, N? H, S? H, and O? H insertion, alkene aziridination, and nitrene C? H insertion with turnover frequencies up to 1950 min?1. The use of chiral [Ru(D4‐Por)(BIMe)2] ( 1 g ) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % ee. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the trans axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal–carbene reaction intermediate. 相似文献
10.
Inmaculada Beloso Jesús Castro Jos A. GarcíaVzquez Paulo PrezLourido Jaime Romero Antonio Sousa 《无机化学与普通化学杂志》2003,629(2):275-284
Electrochemical oxidation of cadmium in an acetonitrile solution of N‐2‐pyridyl‐sulfonamides (HL) afforded cadmium coordination compounds of composition [CdL2]. Heteroleptic complexes of composition [CdL2L′] (L′ = 2, 2′‐bipyridine or 1, 10‐phenanthroline) were obtained when the coligand L′ was added to the electrolytic phase. The crystal structures of several compounds have been determined by X‐ray diffraction. In all cases the cadmium atom is hexacoordinated, but the coordinative behaviour of the N‐2‐pyridyl‐sulfonamide ligand depends on the location of the substituents in the pyridyl ring. When the substituent is in position 3, the ligands act as N, O‐donors. In all other cases, the ligands act as N, N′‐bidentate systems. 相似文献
11.
Larica Pathaw Themmila Khamrang Balasubramaniam Selvakumaran Mariappan Murali Pitchan Arul Prakash Mohamed Sultan Mohamed Jaabir Marappan Velusamy 《应用有机金属化学》2021,35(1)
Copper(I) complexes of the types [Cu(N–N)(PPh3)2]NO3 (LC41–LC44) and [Cu(N–N)(PPh3)(NO3)] (LC45) carrying 3‐substituted 1‐pyridine‐2‐ylimidazo[1,5‐a]pyridine (N–N) derivatives and triphenylphosphine (PPh3) ligands have been prepared. The synthesized copper(I)–phosphine complexes were fully characterized by NMR, IR, ESI‐MS and UV–visible spectroscopy as well as by cyclic voltammetry. Selected structures such as LC42, LC43 and LC45 were additionally analysed by single‐crystal X‐ray method, which show that copper(I) centre adopts a highly distorted tetrahedral geometry. The 1H and 13C NMR spectral data of the complexes throw light on the nature of metal–ligand bonding. They display dπ–π* metal‐to‐ligand charge transfer (MLCT) transition and show quasireversible CuI/CuII metal oxidation. Among the copper(I)–phosphine complexes, LC41–LC44 exhibit moderate cytotoxicity (IC50: 24 h, 67–74 μM; 48 h, 58–70 μM) against human lung epithelial adenocarcinoma A549 cells, whereas LC45 displays the best activity (IC50: 24 h, 42 μM; 48 h, 34 μM) for A549 cancer cell line, which is better than that of the commercial antitumor drug cisplatin. All the complexes also displayed excellent selectivity by being relatively inactive against the human lung epithelial L132 normal cell line with selectivity index (SI) values ranging from 3.4 to 7.4. The complexes block cell cycle progression of A549 cells in G0/G1 phase. FACSVerse analyses are suggestive of reactive oxygen species (ROS) generation and apoptotic cell death induced by the LC41, LC43 and LC45. The induction of apoptosis in A549 cells was shown by Annexin V with propidium iodide (PI) and 4′,6‐diamidino‐2‐phenylindole (DAPI) staining methods and established the ability of LC41, LC43 and LC45 to accumulate in the cell nuclei. 相似文献
12.
Supramolecular Wiring of Benzo‐1,3‐chalcogenazoles through Programmed Chalcogen Bonding Interactions
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Dr. Adrian Kremer Dr. Andrea Fermi Nicolas Biot Prof. Johan Wouters Prof. Dr. Davide Bonifazi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(16):5665-5675
The high‐yielding synthesis of 2‐substituted benzo‐1,3‐tellurazoles and benzo‐1,3‐selenazoles through a dehydrative cyclization reaction has been reported, giving access to a large variety of benzo‐1,3‐chalcogenazoles. Exceptionally, these aromatic heterocycles proved to be very stable and thus very handy to form controlled solid‐state organizations in which wire‐like polymeric structures are formed through secondary N???Y bonding interactions (SBIs) engaging the chalcogen (Y=Se or Te) and nitrogen atoms. In particular, it has been shown that the recognition properties of the chalcogen centre at the solid state could be programmed by selectively barring one of its σ‐holes through a combination of electronic and steric effects exerted by the substituent at the 2‐position. As predicted by the electrostatic potential surfaces calculated by quantum chemical modelling, the pyridyl groups revealed to be the stronger chalcogen bonding acceptors, and thus the best ligand candidate for programming the molecular organization at the solid state. In contrast, the thiophenyl group is an unsuitable substituent for establishing SBIs in this molecular system as it gives rise to chalcogen–chalcogen repulsion. The weaker chalcogen donor properties of the Se analogues trigger the formation of feeble N???Se contacts, which are manifested in similar solid‐state polymers featuring longer nitrogen–chalcogen distances. 相似文献
13.
《Angewandte Chemie (International ed. in English)》2017,56(10):2720-2724
N‐Heterocyclic carbene based pincer ligands bearing a central silyl donor, [CSiC]−, have been envisioned as a class of strongly σ‐donating ligands that can be used for synthesizing electron‐rich transition‐metal complexes for the activation of inert bonds. However, this type of pincer ligand and complexes thereof have remained elusive owing to their challenging synthesis. We herein describe the first synthesis of a CSiC pincer ligand scaffold through the coupling of a silyl–NHC chelate with a benzyl–NHC chelate induced by one‐electron oxidation in the coordination sphere of a cobalt complex. The monoanionic CSiC ligand stabilizes the CoI dinitrogen complex [(CSiC)Co(N2)] with an unusual coordination geometry and enables the challenging oxidative addition of E−H bonds (E=C, N, O) to CoI to form CoIII complexes. The structure and reactivity of the cobalt(I) complex are ascribed to the unique electronic properties of the CSiC pincer ligand, which provides a strong trans effect and pronounced σ‐donation. 相似文献
14.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(10):2764-2768
N‐Heterocyclic carbene based pincer ligands bearing a central silyl donor, [CSiC]−, have been envisioned as a class of strongly σ‐donating ligands that can be used for synthesizing electron‐rich transition‐metal complexes for the activation of inert bonds. However, this type of pincer ligand and complexes thereof have remained elusive owing to their challenging synthesis. We herein describe the first synthesis of a CSiC pincer ligand scaffold through the coupling of a silyl–NHC chelate with a benzyl–NHC chelate induced by one‐electron oxidation in the coordination sphere of a cobalt complex. The monoanionic CSiC ligand stabilizes the CoI dinitrogen complex [(CSiC)Co(N2)] with an unusual coordination geometry and enables the challenging oxidative addition of E−H bonds (E=C, N, O) to CoI to form CoIII complexes. The structure and reactivity of the cobalt(I) complex are ascribed to the unique electronic properties of the CSiC pincer ligand, which provides a strong trans effect and pronounced σ‐donation. 相似文献
15.
Volodimir D. Vreshch Andrey B. Lysenko Harald Krautscheid Konstantin V. Domasevitch 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):m443-m447
In bis[1‐(3‐pyridyl)butane‐1,3‐dionato]copper(II) (the Cu atom occupies a centre of inversion), [Cu(C9H8NO2)2], (I), and bis[1‐(4‐pyridyl)butane‐1,3‐dionato]copper(II) methanol solvate, [Cu(C9H8NO2)2]·CH3OH, (II), the O,O′‐chelating diketonate ligands support square‐planar coordination of the metal ions [Cu—O = 1.948 (1)–1.965 (1) Å]. Weaker Cu⋯N interactions [2.405 (2)–2.499 (2) Å], at both axial sides, occur between symmetry‐related bis(1‐pyridylbutane‐1,3‐dionato)copper(II) molecules. This causes their self‐organization into two‐dimensional square‐grid frameworks, with uniform [6.48 Å for (I)] or alternating [4.72 and 6.66 Å for (II)] interlayer separations. Guest methanol molecules in (II) reside between the distal layers and form weak hydrogen bonds to coordinated O atoms [O⋯O = 3.018 (4) Å]. 相似文献
16.
Molecular recognition continues to be an area of keen interest for supramolecular chemists. The investigated [M( L )2]2+ metallo‐ligands (M=PdII, PtII, L =2‐(1‐(pyridine‐4‐methyl)‐1 H‐1,2,3‐triazol‐4‐yl)pyridine) form a planar cationic panel with vacant pyridyl binding sites. They interact with planar neutral aromatic guests through π–π and/or metallophilic interactions. In some cases, the metallo‐ligands also interacted in the solid state with AgI either through coordination to the pendant pyridyl arms, or through metal–metal interactions, forming coordination polymers. We have therefore developed a system that reliably recognises a planar electron‐rich guest in solution and in the solid state, and shows the potential to link the resultant host–guest adducts into extended solid‐state structures. The facile synthesis and ready functionalisation of 2‐pyridyl‐1,2,3‐triazole ligands through copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) “click” chemistry should allow for ready tuning of the electronic properties of adducts formed from these systems. 相似文献
17.
Qi Shi Robert J. Thatcher John Slattery Dr. Pardeep S. Sauari Adrian C. Whitwood Dr. Patrick C. McGowan Dr. Richard E. Douthwaite Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(42):11346-11360
A range of N‐donor ligands based on the 1H‐pyridin‐(2E)‐ylidene (PYE) motif have been prepared, including achiral and chiral examples. The ligands incorporate one to three PYE groups that coordinate to a metal through the exocyclic nitrogen atom of each PYE moiety, and the resulting metal complexes have been characterised by methods including single‐crystal X‐ray diffraction and NMR spectroscopy to examine metal–ligand bonding and ligand dynamics. Upon coordination of a PYE ligand to a proton or metal‐complex fragment, the solid‐state structures, NMR spectroscopy and DFT studies indicate that charge redistribution occurs within the PYE heterocyclic ring to give a contribution from a pyridinium–amido‐type resonance structure. Additional IR spectroscopy and computational studies suggest that PYE ligands are strong donor ligands. NMR spectroscopy shows that for metal complexes there is restricted motion about the exocyclic C? N bond, which projects the heterocyclic N‐substituent in the vicinity of the metal atom causing restricted motion in chelating‐ligand derivatives. Solid‐state structures and DFT calculations also show significant steric congestion and secondary metal–ligand interactions between the metal and ligand C? H bonds. 相似文献
18.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7333-7338
Alkenyl‐to‐allyl 1,4‐rhodium(I) migration enables the generation of nucleophilic allylrhodium(I) species by remote C−H activation. This new mode of reactivity was employed in the diastereoselective reaction of arylboron reagents with substrates containing a 1,3‐enyne tethered to a ketone, to give products containing three contiguous stereocenters. The products can be obtained in high enantioselectivities using a chiral sulfur‐alkene ligand. 相似文献
19.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(8):613-619
Functionalized acid amides are widely used in biology, medicine, environmental chemistry and many other areas. Among them, pyridine‐substituted amides, in particular N‐(pyridin‐2‐yl)acetamide and its derivatives, play an important role due to their excellent chelating properties. The donor properties of these ligands can be effectively modified by introducing electron‐donating substituents (e.g. alkyl groups) into the heterocycle. On the other hand, substituents in the α‐position of the pyridine ring can create steric hindrance, which significantly influences the coordination number and geometry. To achieve a better understanding of these effects, copper(II) complexes with sterically demanding N‐(6‐methylpyridin‐2‐yl)acetamide ligands (L ) and monoanions of different size, shape and coordination ability have been chosen as model compounds. The crystal structures of three new compounds, bromidobis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) bromide, [CuBr(C8H10N2O)]Br, (I), aquabis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) dinitrate, [Cu(C8H10N2O)(H2O)](NO3)2, (II), and aquabis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) bis(perchlorate), [Cu(C8H10N2O)(H2O)](ClO4)2, (III), have been determined by single‐crystal X‐ray diffraction analysis. It has been shown that the presence of the 6‐methyl group results in either a distorted square‐pyramidal or a distorted trigonal–bipyramidal coordination geometry around the CuII centres instead of the typical octahedral geometry observed when the methyl substituent is absent or occupies any other position on the pyridine ring. Moreover, due to the steric hindrance provided by the L ligands, only the bromide ligand, the smallest of the series, enters into the first coordination sphere of the CuII ion in (I). In (II) and (III), the vacant coordination site of the CuII ion is occupied by a water molecule, while the nitrate and perchlorate anions are not involved in coordination to the metal centre. The structures of (I)–(III) are characterized by the presence of one‐dimensional infinite chains formed by hydrogen bonds of the types N—H…Br [in (I)], N—H…O and O—H…O [in (II) and (III)] between the amide groups of the L ligands, the coordinated water molecules and the uncoordinated anions. The hydrogen‐bonded chains are further interconnected through π–π stacking interactions between the pyridine rings of the L ligands, with approximate interplanar separations of 3.5–3.6 Å. 相似文献
20.
Prof. Dr. Hai‐Bin Zhu Shu‐Ying Zhang Xin Lu Wen‐Na Yang Prof. Dr. Shao‐Hua Gou Jing Chen 《无机化学与普通化学杂志》2011,637(10):1423-1426
Reactions of the ligand 2 ‐ MTPP [2‐MTPP = 2‐(methylthio)‐4‐(pyridin‐2‐yl)pyrimidine] with AgNO3 and CuI produced dinuclear silver(I) ( 1 ) and copper(I) ( 2 ) complexes, respectively. Both complexes adopt a chair‐like structure in which two 2 ‐ MTPP ligands and two metal ions are joined together through M–N and M–S coordination bonds. The luminescence properties of both complexes were investigated in solid state at room temperature. 相似文献