- Synthesis, crystal structures, in vitro anticancer, and in vivo acute oral toxicity studies of bis-imidazolium/benzimidazolium salts and respective dinuclear Ag(I)- N -heterocyclic carbene complexes
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The synthesis, spectral (FT-IR and NMR), and structural studies of 1,1′-methylene linked 3,3′-2-cyanobenzyl bis-imidazolium salt (L1) and respective dinuclear Ag(I)-NHC complex (C1) are reported The structures of both compounds were established through single-crystal X-ray diffraction C1 has a short Ag-Ag separation of 3.16 A Both L1 and C1 were tested for potential against leukemia (k562) cell line For comparison, para-xylyl linked bis-benzimidazolium salts (L2-L4) and their dinuclear Ag(I)-NHC complexes (C2-C4) were synthesized and tested against the same cell line (K562) The IC50 values proved that L2-L4 and C2-C4 are many fold more active than L1 and C1 The mechanism of action and structure activity relationship are discussed In vivo oral acute toxicity study (sighting study) was carried out which depicts that 2000 mg/kg dose of selected compounds is an appropriate and safe dose for conducting main study on animals 2013
- Haque, Rosenani A.,Hasanudin, Noorhafizah,Iqbal, Muhammad Adnan,Ahmad, Ashfaq,Hashim, Suzana,Abdul Majid, Ams,Ahamed, Mohamed B Khadeer
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- Nickel and Platinum PCP Pincer Complexes Incorporating an Acyclic Diaminoalkyl Central Moiety Connecting Imidazole or Pyrazole Rings
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This work explores avenues toward PCP pincer complexes with acyclic diaminocarbene central moieties that are suitable for ligand-assisted reactivity involving the carbene carbon. For this purpose, diphosphine chelating ligands 1 and 2, with bis(imidazolyl)methyl and bis(pyrazolyl)methyl backbones, respectively, were prepared in two high-yield synthetic steps. Nickel(II) and platinum(II) dihalide complexes 3 and 6, incorporating 1, were prepared and converted into PCP pincer ligands 5 and 7 upon deprotonation with KHMDS. Chelated nickel(I) complex 4 was obtained as a byproduct to 3. Although the solid-state structures of 5 and 7 presented geometric strain at the diaminomethyl carbon, this moiety could not be converted into a diaminocarbene by proton or hydride abstraction. 7 could be converted into platinum(IV) analog 8 by oxidation with PhICl2. Ligand 2 proved more versatile than 1, or less dependable in its behavior, generating P,N-chelating cobalt(II) dibromide complex 9. Easily accessible ligands 1 and 2 provide a new and versatile PCP pincer platform.
- Puerta Lombardi, Braulio M.,Brown, Rudy M.,Gendy, Chris,Chang, Chia Yun,Chivers, Tristram,Roesler, Roland
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- Cuprous Iodide Pseudopolymorphs Based on Imidazole Ligand and Their Luminescence Thermochromism
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Two cuprous iodide pseudopolymorphs, formulated as [(Cu4I4)(MBI)2]∞ (MBI = 1,1′-methylene-bis(imidazole)) with an irregular cubane-like Cu4I4 cluster as tetrahedrally coordinated secondary building unit and imidazole derivative as bridging ligand, have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both of two compounds only exhibited a single broad low-energy cluster-centered (3CC) triplet emission band between room temperature and 77 K. Of particular interest, these two Cu4I4-imidazole pseudopolymorphs still displayed thermochromic luminescence originating from a red shift of such tunable single cluster-centered triplet emission, being different from that observed in the previously reported Cu4I4-pyridine system by balancing temperature-dependent multiple emissions (high-energy and low-energy) derived from their energetically distinct triplet states.
- Fu, Zhixing,Lin, Jian,Wang, Le,Li, Cheng,Yan, Wenbo,Wu, Tao
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- A mixed ligand route for the construction of tetrahedrally coordinated porous lithium frameworks
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Reported here are two 4-connected 3D frameworks based on monomeric lithium nodes, which are synthesized through a mixed ligand route. By combining a negatively charged imidazole ligand and a neutral bis(imidazolyl)methane ligand (or one of its derivatives), neutral frameworks adopting chiral quartz-dual and diamond topologies have been obtained. These materials have low framework density and can reversibly adsorb hydrogen gas. The Royal Society of Chemistry 2011.
- Zhao, Xiang,Wu, Tao,Bu, Xianhui,Feng, Pingyun
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- Exploring different coordination modes of the first tetradentate NHC/1,2,3-triazole hybrid ligand for group 10 complexes
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Synthesis and characterisation of the first tetradentate N-heterocyclic carbene (NHC)/1,2,3-triazole hybrid ligand obtained by means of copper(i) catalyzed "click" chemistry and its application for the synthesis of group 10 complexes is reported. For pall
- Schlagintweit, Jonas F.,Nguyen, Linda,Dyckhoff, Florian,Kaiser, Felix,Reich, Robert M.,Kühn, Fritz E.
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- Linear Pyrazole-bridged Tetra(N-heterocyclic carbene) Ligands and Their Hexanuclear Silver(I) Complexes
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New hybrid ligands are reported that combine two types of popular donor groups within a single linear scaffold, viz., a central pyrazolate bridge and two appended bis(N-heterocyclic carbene) units; the ligand strands thus provide two potentially tridentate {NCC} compartments. The pyrazole/tetraimidazolium proligands, [H5L1](PF6)4 and [H5L2](PF6)4, were synthesized via multi-step protocols, and the NH prototropy of [H5L1](PF6)4 was examined by variable temperature (VT) NMR spectroscopy, giving solvent dependent activation parameters (ΔH? = 27.6 kJ·mol–1, ΔS? = –125 J·mol–1·K–1 in [D3]MeCN; ΔH? = 40.4 kJ·mol–1, ΔS? = –86.9 J·mol–1·K–1 in [D6]DMSO) that are in the range typical for pyrazoles. Reaction of the proligands with Ag2O gave hexametallic complexes [Ag6(L1)2](PF6)4 and [Ag6(L2)2](PF6)4 that involve all six potential donor atoms of the ligands, viz. the four CNHC and two Npz donors, in metal coordination. X-ray crystallography revealed a chair-like central {Ag6} deck in both complexes but different arrangements of the ligand strands, which goes along with significantly different AgI···AgI distances that indicate more pronounced argentophilic interactions in case of [Ag6(L1)2]4+.
- Resch, Stefan G.,Dechert, Sebastian,Meyer, Franc
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- Iodide selective fluorescent anion receptor with two methylene bridged bis-imidazolium rings on naphthalene
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We have designed and synthesized fluorescent anion receptor 2, bearing two methylene bridged bis-imidazolium ring on 1,8-positions of naphthalene. Anion binding studies carried out using fluorescence spectroscopy and 1H NMR revealed that this c
- Kim, Hyungil,Kang, Jongmin
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- Metallo-cryptophanes decorated with Bis-N-heterocyclic carbene ligands: Self-assembly and guest uptake into a nonporous crystalline lattice
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Pd3L2 metallo-cryptophane cages with cyclotriveratrylene-type L ligands can be stabilized by use of a bis-N-heterocyclic carbene as an auxiliary cis-protecting ligand, while use of more common protecting chelating ligands such as ethylenediamine saw a Pd3L2 to Pd6L8 rearrangement occur in solution. The crystalline Pd3L2 complexes act as sponges, taking up 1,2-dichorobenzene or iodine in a single-crystal-to-single-crystal fashion despite not exhibiting conventional porosity.
- Henkelis, James J.,Carruthers, Christopher J.,Chambers, Scott E.,Clowes, Rob,Cooper, Andrew I.,Fisher, Julie,Hardie, Michaele J.
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- Sulfonate- or carboxylate-functionalized N-heterocyclic bis-carbene ligands and related water soluble silver complexes
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New N-heterocyclic carbene ligand precursors {H2C(HTz R)2} and {H2C(HImR)2} (HTz = 1,2,4-triazole; HIm = imidazole; R = PrSO3 or EtCOO) were obtained starting from the compounds bis(1,2,4-triazol-1-yl)methane and bis(imidazol-1-yl)methane. The related silver(i) carbene complexes were prepared in degassed water solution by treatment of the triazolium or imidazolium species with Ag2O, resulting in well-characterized and water soluble bimetallic complexes of general formula {Na2[H2C(Tz R)2]2Ag2} and {Na2[H 2C(ImR)2]2Ag2}. In these metallacycles every silver atom is coordinated to two triazolin- or imidazolin-2-ylidene rings, belonging to two different dicarbene units.
- Papini, Grazia,Pellei, Maura,Gioia Lobbia, Giancarlo,Burini, Alfredo,Santini, Carlo
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- Dimeric gold bis(carbene) complexes by transmetalation in water
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Due to its cost, environmental benefits, and safety advantages, water has become more and more important as a solvent for catalytic reactions and constitutes the best environment for biomedical applications. Therefore, watersoluble and water-stable metal complexes containing strong - donor ligands such as N-heterocyclic carbenes (NHCs) are of great interest in modern coordination chemistry. In this paper we present the successful preparation of two new dinuclear gold(I)bis(NHC) complexes in water, by applying the AgNHC transfer route. This green synthetic strategy is valuable for gold(I) compounds involving N-functionalized neutral and dianionic bis(NHC) ligands. These two water-soluble compounds were analyzed by spectroscopic methods and by X-ray diffraction. Furthermore, ab initio and DFT calculations on the corresponding dinuclear gold complexes illustrate the important influence of the electrostatic environment of the dinuclear entity on the aurophilic interactions and help to understand the molecular arrangement presented in this paper.
- Cure, Jeremy,Poteau, Romuald,Gerber, Iann C.,Gornitzka, Heinz,Hemmert, Catherine
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- Syntheses of Symmetric and Unsymmetric Bis-imidazole Derivatives Using Phase-Transfer Catalysis
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A convenient method for the preparation of symmetric and unsymmetric bisimidazole derivatives was established. The symmetric bisimidazolylmethane derivatives 1a–9a was prepared with 2-substituted imidazole derivatives 1–9 as reaction materials. However, the symmetric and unsymmetric bisimidazolylmethane derivatives 10a–12a and 10b–12b was obtained, respectively. With 4-position with the azo-groups imidazole derivatives 10–12 were used as reaction materials. All these compounds have been structurally characterized by the NMR, ESI-MS, and EA. And 8a and 12a were also characterized by the X-ray single crystal diffusion.
- Zhang, Kun-Peng,Jin, Tian-Qi,Zhou, Jun-Qiang,Ma, Ting-Ting,Jin, Chuan-Ming
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- N-Heterocyclic Carbene-Stabilized Ultrasmall Gold Nanoclusters in a Metal-Organic Framework for Photocatalytic CO2 Reduction
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Ultrafine gold nanoclusters (Au-NCs) are susceptible to migrate and aggregate, even in the porosity of many crystalline solids. N-heterocyclic carbenes (NHCs) are a class of structurally diverse ligands for the stabilization of Au-NCs in homogeneous chemi
- Ai, Jing,Fei, Honghan,Han, Lu,Jiang, Yilin,Song, Xueling,Weinert, Micha,Yu, Yuan,Zhang, Xu
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supporting information
p. 17388 - 17393
(2021/07/06)
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- Selective Catalytic Isomerization of β-Pinene Oxide to Perillyl Alcohol Enhanced by Protic Tetraimidazolium Nitrate
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A series of tetraimidazolium salts with different anions was prepared and applied in the isomerization of β-pinene oxide. After examining the activity of different catalysts, a remarkable enhancement of the selectivity of perillyl alcohol (47 %) was obtained over [PEimi][HNO3]4 under mild reaction conditions and using DMSO as the solvent. Furthermore, noncovalent interactions between solvent molecules and the catalyst were found by FT-IR spectroscopy and confirmed by computational chemistry. The homogeneous catalyst showed excellent stability and was reused up to six times without significant loss.
- Li, Hui,Liu, Jian,Zhao, Juan,He, Huiting,Jiang, Dabo,Kirk, Steven Robert,Xu, Qiong,Liu, Xianxiang,Yin, Dulin
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p. 477 - 485
(2021/05/04)
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- Mixing divalent ionic liquids: effects of charge and side-chains
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We have prepared novel divalent ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl)imide anion where two charged imidazolium groups in the cations are either directly bound to each other or linked by a single atom. We assessed the influence of the side-chain functionality and divalency on their physical properties and on the thermodynamics of mixing. The results indicate that shortening the spacer of a divalent IL reduces its thermal stability and increases its viscosity. Mixtures of divalent and monovalent ILs show small but significant deviations from ideality upon mixing. These deviations appear to depend primarily on the (mis)match of the nature and length of the cation side-chain. The non-ideality imposed by mixing ILs with different side-chains appears to be enhanced by the increase in formal charge of the cations in the mixture.
- Bakis, Eduards,van den Bruinhorst, Adriaan,Pison, Laure,Palazzo, Ivan,Chang, Thomas,Kjellberg, Marianne,Weber, Cameron C.,Costa Gomes, Margarida,Welton, Tom
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p. 4624 - 4635
(2021/03/15)
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- Functionalized ionic liquid based on binuclear structure, preparation method thereof and use method of functionalized ionic liquid for degrading lignocellulose
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The invention discloses functionalized ionic liquid based on a binuclear structure, a preparation method thereof and a use method of the functionalized ionic liquid for degrading lignocellulose, whichbelong to the technical field of chemical engineering. The ionic liquid prepared by the invention contains [PF6] or [N(CF3SO2)2] hydrophobic group and Cl or Br hydrophilic group at the same time, and the solubility of the ionic liquid and water is different under different temperature conditions. Therefore, the solubility of the ionic liquid and the water can be controlled by adjusting the temperature and the water quantity; the ionic liquid can be mutually dissolved with water at the temperature of 80 DEG C or above and cannot be dissolved with water at the room temperature or below, so that the problem that after biomass lignocellulose is degraded by existing ionic liquid to prepare reducing sugar, a reducing sugar aqueous solution and an ionic liquid aqueous solution of a product are difficult to separate is solved, and the recycling and reusing efficiency of the ionic liquid is improved. In addition, the ionic liquid also has an acidic catalysis function and has the advantages of being capable of catalyzing lignocellulose to be degraded into reducing sugar, improving the yield of the reducing sugar and the like.
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Paragraph 0036; 0041
(2020/05/05)
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- Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response
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Bisimidazolium receptors, tagged with chromophoric pyrene at one end and linked to an n-alkyl chain at the other, underwent self-assembly in aqueous media depending on the length of the alkyl segment. The amphiphilic derivatives having n-decyl or longer chains, formed nano-assemblies with cyanic-green emission resulting from the stacked pyrene chromophores in the aggregates. The presence of positive surface charges on the multivalent aggregates led to ATP binding which was accompanied by a significant increase in the excimeric emission intensity. This provided a convenient way of monitoring ATP binding in a “turn-on” mode and an efficient detection of ATP was achieved in aqueous buffer and also in buffer containing 150 mM NaCl at physiological pH value. Furthermore, the multivalent aggregates demonstrated a significant selectivity in ATP detection over ADP, AMP and pyrophosphate.
- Biswas, Rakesh,Ghosh, Surya,Bhaumik, Shubhra Kanti,Banerjee, Supratim
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supporting information
p. 2728 - 2738
(2020/12/09)
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- Synthesis, conformational analysis and antibacterial activity of Au(I)-Ag(I) and Au(I)-Hg(II) heterobimetallic N-heterocyclic carbene complexes
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A post-synthetic modification and metallation procedure has been used to prepare a family of heterobimetallic Au(I)-Ag(I) and Au(I)-Hg(II) complexes featuring either symmetrical or asymmetrical bis-N-heterocyclic carbene ligands with methylene or ethylene linker groups. This synthetic approach is versatile and allows for the synthesis of heterobimetallic complexes bearing asymmetrical ligands that differ in the nature of the NHC wingtip substituents (dimethyl, diethyl or ethyl-methyl) and for the selective placement of the different metal ions. The synthesised complexes were characterised using 1H and 13C NMR spectroscopy and high resolution mass spectrometry (HR-MS) and in the case of complexes 4a, 5b and 8b by X-ray crystallography. The complexes of the methylene linked bridging ligands display conformational isomerism in solution and the conformations adopted by selected compounds were examined using variable temperature (VT) 1H NMR studies. The antibacterial properties of the heterobimetallic Au(I)-Ag(I) complexes in addition to the corresponding homobimetallic Ag(I)2, Au(I)2 complexes were evaluated against clinically relevant Gram-positive and Gram-negative bacterial strains. The homobimetallic Au(I)2 complex and precursor pro-ligand displayed no antibacterial activity up to 256 μg mL-1, whereas the homobimetallic Ag(I)2 was active against all Gram-positive and Gram-negative bacterial strains tested (MIC = 8-32 μg mL-1). Interestingly, both Au(I)-Ag(I) heterobimetallic complexes displayed similar broad-spectrum activity (MIC = 4-32 μg mL-1) to the Ag(I)2 homobimetallic complex. This journal is
- Li, Zili,MacKie, Emily R. R.,Ramkissoon, Pria,Mather, Joel C.,Wiratpruk, Nuchareenat,Soares Da Costa, Tatiana P.,Barnard, Peter J.
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supporting information
p. 12820 - 12834
(2020/11/23)
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- Synthesis method and application of two N-heterocyclic carbene palladium metal complexes
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The invention discloses a synthesis method and an application of two N-heterocyclic carbene palladium metal complexes, relates to a synthesis method and an application of metal complexes, concretely relates to a preparation method of two novel N-heterocyc
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Paragraph 0009; 0011
(2020/04/06)
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- Transfer hydrogenation of levulinic acid from glycerol and ethanol using water-soluble iridium N-heterocyclic carbene complexes
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The upgrading of biomass derivatives to biofuels and chemicals through transfer hydrogenation (TH) is attractive relative to direct hydrogenation, especially when the hydrogen donors can be sourced renewably. Here we report the first process that uses glycerol, a renewable waste material from biodiesel processing, as a hydrogen donor in the catalytic TH of a biomass-derived platform chemical, levulinic acid, to selectively afford γ-hydroxyvaleric acid (GHV) and lactic acid (LA). GHV can be further converted to γ-valerolactone (GVL), a widely used platform chemical. Levulinic acid can be used directly, without esterification, which is typically needed for transfer hydrogenation. The process is efficiently facilitated by robust iridium N-heterocyclic carbene (NHC) complexes with sulfonate functional groups at low catalyst loading (1–10 ppm), affording quantitative conversion of levulinic acid in the presence of KOH to GHV, with >100,000 TON in 2 h at 150 °C, using 1 ppm catalyst. The most prolific catalyst, [(NHC-SO3-)2(CO)2Ir]Na, can also facilitate transfer hydrogenation from other hydrogen donors, such as 2-propanol, potassium formate, and most notably, ethanol, which can also be derived from renewables. Ethanol is a highly efficient hydrogen donor for levulinic acid using this catalyst, affording >7,000 turnovers in 2 h using 10 ppm catalyst.
- Culley, Keira,Heltzel, Jacob,Lemcoff, Gabriel,Sandefur, Evan,Voutchkova-Kostal, Adelina,Wang, Kai
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supporting information
(2020/05/18)
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- Method for preparing an imidazole
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The invention discloses a preparation method for imidazole. 2,2-diethoxyethylamine and malonamide are employed for preparing biimidazole, and biimidazole is used to prepare imidazole. Compared with the prior art, the method has the total conversion rate of 91% through continuous optimization of reaction conditions and other reagent usage amount, and the total conversion rate is far higher than that of a conventional technology. The preparation method is mild in reaction conditions, a solvent and a catalyst employed in the reaction process can be recovered and reused, and the method is relatively low in cost and is practicable.
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Paragraph 0031-0035
(2017/03/14)
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- Antibacterial activity of aminals and hemiaminals of pyrazole and imidazole
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Antibacterial activity of 1,1'-methylenedipyrazole (AM1), 1-hydroxymethylpyrazole (SAM1), 1,1'-methylenediimidazole (AM2), and 1-hydroxymethylimidazole (SAM2) has been tested against reference and clinical strains by both difusimetric and broth dilution methods. Overall, the minimal inhibitory concentrations of tested compounds ranged from 180 to 270 μg/ml, while the minimal bactericidal concentrations were between 360 and 720 μg/ml. Comparative assessment with phenol and formaldehyde shows that AM1, AM2, SAM1, and SAM2 have moderate to good antibacterial activity.
- Lupsor, Simona,Aonofriesei, Florin,Iovu, Mircea
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p. 3035 - 3042,8
(2020/08/24)
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- 18-atom-ringed macrocyclic tetra-imidazoliums for preparation of monomeric tetra-carbene complexes
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18-Atom-ringed macrocyclic tetra-imidazolium ligands have been synthesized by a two-step procedure and are the smallest free tetra-imidazoliums to date. The structures of the tetra-imidazoliums were characterized by multinuclear NMR and high-resolution ES
- Bass, Heather M.,Cramer, S. Alan,Price, Julia L.,Jenkins, David M.
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scheme or table
p. 3235 - 3238
(2010/09/06)
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- USE OF PT-AND PD-BIS-AND TETRA-CARBON COMPLEXES WITH BRIDGED CARBON LIGANDS IN OLEDS
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The use of Pt- and Pd-bis- and tetracarbene complexes with bridged carbene ligands in organic light-emitting diodes, organic light-emitting diodes comprising at least one aforementioned Pt- or Pd-carbene complex, at least one transition metal-carbene comp
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(2010/01/31)
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- PHASE TRANSFER CATALYSIS WITHOUT SOLVENT. SYNTHESIS OF BISAZOLYLALKANES
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The reaction of azoles and benzazoles with dihalomethanes and dihaloethanes was performed in the absence of solvent.This method provides a general procedure for the synthesis of bisazolylmethanes and ethanes.No solvent was used during the reaction and, when possible, during the work-up.
- Diez-Barra, Enrique,Hoz, Antonio de la,Sanchez-Migallon, Ana,Tejeda, Juan
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p. 1365 - 1373
(2007/10/02)
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- N-Polyazolylmethanes. III. Synthese et etude rmn du proton des derives du methylene-1,1' diimidazole et du methylene-1,1' dibenzimidazole
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Several quaternary salts derived from 1,1'-methylenediimidazole and 1,1'-methylenedibenzimidazole have been prepared.A comparative study with the salts derived from 1-methylimidazole and 1-methylbenzimidazole has been carried out using proton magnetic resonance.Nuclear Overhauser effect and shift reagents have been used for the assignment of heterocyclic protons.
- Claramunt, Rosa Maria,Elguero, Jose,Meco, Teresa
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p. 1245 - 1249
(2007/10/02)
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- N-Polyazolylmethanes. 1. Synthesis and NMR Study of N,N'-Diazolylmethanes
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Thirteen N,N'-diazolylmethanes, including derivatives of pyrazole, imidazole, 1,2,4-triazole, benzimidazole and indazole were prepared by reaction of azoles with methylene chloride under phase transfer catalysis conditions.The relative amounts of isomeric mixtures obtained with 'asymmetric' azoles or with equimolar mixtures of azoles are compared with literature results on monoalkylation of azoles.Proton and carbon-13 nmr spectra of the N,N'-diazolylmethanes are discussed.
- Julia, Sebastian,Sala, Pilar,Mazo, Jose del,Sancho, Manuel,Ochoa, Carmen,etc.
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p. 1141 - 1145
(2007/10/02)
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