共查询到20条相似文献,搜索用时 15 毫秒
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Dr. Léa Delacour Dr. Naoko Kotera Dr. Ténin Traoré Sébastien Garcia‐Argote Céline Puente Dr. François Leteurtre Dr. Edmond Gravel Dr. Nawal Tassali Dr. Céline Boutin Estelle Léonce Dr. Yves Boulard Dr. Patrick Berthault Dr. Bernard Rousseau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6089-6093
We describe the synthesis of a highly water‐soluble cryptophane 1 that can be seen as a universal platform for the construction of 129Xe magnetic resonance imaging (MRI)‐based biosensors. Compound 1 is easily functionalized by Huisgen cycloaddition and exhibits excellent xenon‐encapsulation properties. In addition, 1 is nontoxic at the concentrations typically used for hyperpolarized 129Xe MRI. 相似文献
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Thomas J. Carruthers Dr. Paul D. Carr Dr. Choy‐Theng Loh Dr. Colin J. Jackson Prof. Gottfried Otting 《Angewandte Chemie (International ed. in English)》2014,53(51):14269-14272
Heterodinuclear metalloenzymes are an important class of metalloproteins, but determining the location of the different metal ions can be difficult. Herein we present a new NMR spectroscopy method that uses pseudocontact shifts (PCS) to achieve this without assumptions about the coordinating ligands. The approach is illustrated with the dinuclear [FeZn] complex of IMP‐1, which is a prototypical metallo‐β‐lactamase (MβL) that confers resistance to β‐lactam antibiotics. Results from single‐crystal X‐ray diffraction were compromised by degradation during crystallization. With [GaZn]‐IMP‐1 as diamagnetic reference, the PCSs unambiguously identified the iron binding site in fresh samples of [FeZn]‐IMP‐1, even though the two metal centers are less than 3.8 Å apart and the iron is high‐spin Fe3+, which produces only small PCSs. [FeZn]‐MβLs may be important drug targets, as [FeZn]‐IMP‐1 is enzymatically active and readily produced in the presence of small amounts of Fe3+. 相似文献
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Thiol–Ene “Click” Reaction Triggered by Neutral Ionic Liquid: The “Ambiphilic” Character of [hmim]Br in the Regioselective Nucleophilic Hydrothiolation 下载免费PDF全文
Rajesh Kumar Saima Amit Shard Nitin H. Andhare Richa Dr. Arun K. Sinha 《Angewandte Chemie (International ed. in English)》2015,54(3):828-832
Thiol–ene “click” chemistry has emerged as a powerful strategy to construct carbon–heteroatom (C? S) bonds, which generally results in the formation of two regioisomers. To this end, the neutral ionic liquid [hmim]Br has been explored as a solvent cum catalyst for the synthesis of linear thioethers from activated and inactivated styrene derivatives or secondary benzyl alcohols and thiols without the requirement of using a metal complex, base, or free radical initiator. Furthermore, detailed mechanistic investigations using 1H NMR spectroscopy and quadrupole time‐of‐flight electrospray ionization mass spectrometry (Q‐TOF ESI‐MS) revealed that the “ambiphilic” character of the ionic liquid promotes the nucleophilic addition of thiol to styrene through an anti‐Markovnikov pathway. The catalyst recyclability and the extension of the methodology for thiol–yne click chemistry are additional benefits. A competitive study among thiophenol, styrene, and phenyl acetylene revealed that the rate of reaction is in the order of thiol–yne>thiol–ene>dimerization of thiol in [hmim]Br. 相似文献
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John Moraes Thomas Maschmeyer Sébastien Perrier 《Journal of polymer science. Part A, Polymer chemistry》2011,49(13):2771-2782
We describe a facile, one‐pot, two‐step polymerization towards synthesizing block co‐polymers bearing reactive isocyanate functional groups. Reversible addition fragmentation chain transfer (RAFT) polymerization is used to mediate the co‐polymerization of isocyanate‐bearing monomers dimethyl meta‐isopropenyl benzyl isocyanate (TMI) and 2‐isocyanatoethyl methacrylate (ICEMA) with styrene and methyl methacrylate (MMA), respectively. ICEMA was incorporated into the polymer at a faster rate than TMI and its unhindered isocyanate group was found to be more reactive than the hindered isocyanate group of TMI. Both the TMI/styrene and the MMA/ICEMA systems maintain the reactivity of the isocyanate functionality, which was exploited by attaching representative hydroxyl‐bearing small and large molecules as well as solid substrates to the block co‐polymers. Thus, we demonstrate the versatility of the block co‐polymer system as a basis for forming branched polymers or as grafts for a solid substrate. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Organic azides have been somewhat popularized due to their pivotal role in the emerging field of “click chemistry”. A simple approach has been used for the synthesis of uniform nano Fe‐MIL‐88B‐NH2, and a generic postsynthetic modification route has been developed for the synthesis of azide‐modified nano Fe‐MIL‐88B‐N3. The approach also has been used to synthesize the azide‐modified IRMOF‐3(‐N3). These new azide‐modified Fe‐MIL‐88B‐N3 nanocrystals hold promising potential for the applications in the fields of “click chemistry”, nanotechnology devices and nano composite membranes. 相似文献
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Dongxia Wu Xiaohui Song Tao Tang Hanying Zhao 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):443-453
Well‐defined macromolecular brushes with poly(N‐isopropyl acrylamide) (PNIPAM) side chains on random copolymer backbones were synthesized by “grafting from” approach based on click chemistry and reversible addition‐fragmentation chain transfer (RAFT) polymerization. To prepare macromolecular brushes, two linear random copolymers of 2‐(trimethylsilyloxy)ethyl methacrylate (HEMA‐TMS) and methyl methacrylate (MMA) (poly(MMA‐co‐HEMA‐TMS)) were synthesized by atom transfer radical polymerization and were subsequently derivated to azide‐containing polymers. Novel alkyne‐terminated RAFT chain transfer agent (CTA) was grafted to polymer backbones by copper‐catalyzed 1,3‐dipolar cycloaddition (azide‐alkyne click chemistry), and macro‐RAFT CTAs were obtained. PNIPAM side chains were prepared by RAFT polymerization. The macromolecular brushes have well‐defined structures, controlled molecular weights, and molecular weight distributions (Mw/Mn ≦ 1.23). The RAFT polymerization of NIPAM exhibited pseudo‐first‐order kinetics and a linear molecular weight dependence on monomer conversion, and no detectable termination was observed in the polymerization. The macromolecular brushes can self‐assemble into micelles in aqueous solution. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 443–453, 2010 相似文献
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Marat R. Talipov Dmitry G. Khomyakov Ming Xian Qadir K. Timerghazin 《Journal of computational chemistry》2013,34(18):1527-1530
To address a long‐standing problem of finding efficient reactions for chemical labeling of protein‐based S‐nitrosothiols (RSNOs), we computationally explored hitherto unknown (3+2) cycloaddition RSNO reactions with alkynes and alkenes. Nonactivated RSNO cycloaddition reactions have high activation enthalpy (>20 kcal/mol at the CBS‐QB3 level) and compete with alternative S—N bond insertion pathway. However, the (3+2) cycloaddition reaction barriers can be dramatically lowered by coordination of a Lewis acid to the N atom of the —SNO group. To exploit this effect, we propose to use reagents with Lewis acid and a strain‐activated carbon–carbon multiple bond linked by a rigid scaffold, which can react with RSNOs with small activation enthalpies (~5 kcal/mol) and high reaction exothermicities (~40 kcal/mol). The proposed efficient RSNO cycloaddition reactions can be used for future development of practical RSNO labeling reactions. © 2013 Wiley Periodicals, Inc. 相似文献
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“Click” Chemistry Mildly Stabilizes Bifunctional Gold Nanoparticles for Sensing and Catalysis 下载免费PDF全文
Na Li Dr. Pengxiang Zhao Dr. Na Liu María Echeverria Dr. Sergio Moya Dr. Lionel Salmon Dr. Jaime Ruiz Prof. Dr. Didier Astruc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8363-8369
A large family of bifunctional 1,2,3‐triazole derivatives that contain both a polyethylene glycol (PEG) chain and another functional fragment (e.g., a polymer, dendron, alcohol, carboxylic acid, allyl, fluorescence dye, redox‐robust metal complex, or a β‐cyclodextrin unit) has been synthesized by facile “click” chemistry and mildly coordinated to nanogold particles, thus providing stable water‐soluble gold nanoparticles (AuNPs) in the size range 3.0–11.2 nm with various properties and applications. In particular, the sensing properties of these AuNPs are illustrated through the detection of an analogue of a warfare agent (i.e., sulfur mustard) by means of a fluorescence “turn‐on” assay, and the catalytic activity of the smallest triazole–AuNPs (core of 3.0 nm) is excellent for the reduction of 4‐nitrophenol in water. 相似文献
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Cyclometalated Mono‐ and Dinuclear IrIII Complexes with “Click”‐Derived Triazoles and Mesoionic Carbenes 下载免费PDF全文
Dr. Ramananda Maity Stephan Hohloch Prof. Dr. Cheng‐Yong Su Margarethe van der Meer Prof. Dr. Biprajit Sarkar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9952-9961
Orthometalation at IrIII centers is usually facile, and such orthometalated complexes often display intriguing electronic and catalytic properties. By using a central phenyl ring as C?H activation sites, we present here mono‐ and dinuclear IrIII complexes with “click”‐derived 1,2,3‐triazole and 1,2,3‐triazol‐5‐ylidene ligands, in which the wingtip phenyl groups in the aforementioned ligands are additionally orthometalated and bind as carbanionic donors to the IrIII centers. Structural characterization of the complexes reveal a piano stool‐type of coordination around the metal centers with the “click”‐derived ligands bound either with C^N or C^C donor sets to the IrIII centers. Furthermore, whereas bond localization is observed within the 1,2,3‐triazole ligands, a more delocalized situation is found in their 1,2,3‐triazol‐5‐ylidene counterparts. All complexes were subjected to catalytic tests for the transfer hydrogenation of benzaldehyde and acetophenone. The dinuclear complexes turned out to be more active than their mononuclear counterparts. We present here the first examples of stable, isomer‐pure, dinuclear cyclometalated IrIII complexes with poly‐mesoionic‐carbene ligands. 相似文献
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Brad M. Rosen Gerard Lligadas Christian Hahn Virgil Percec 《Journal of polymer science. Part A, Polymer chemistry》2009,47(15):3940-3948
The development of a novel nucleophilic thio‐bromo “Click” reaction, specifically base‐mediated thioetherification of thioglycerol with α‐bromoesters was reported in an earlier article. The combination of this thio‐bromo click reaction with subsequent acylation with 2‐bromopropionyl bromide provides an iterative two‐step divergent growth approach to the synthesis of a new class of poly(thioglycerol‐2‐ propionate) (PTP) dendrimers. In this article, the addition of a third step, the single‐electron transfer living radical polymerization (SET‐LRP) of methyl acrylate (MA), was shown to provides access to a three‐step “branch” and “grow” divergent approach to dendritic macromolecules wherein poly(methyl acrylate) (PMA) connects the branching subunits. This facile methodology can provide a diversity of dendritic macromolecular topologies and will ultimately provide the means to the development of self‐organizable dendritic macromolecules. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3940–3948, 2009 相似文献
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Integrative Chemical Biology Approaches for Identification and Characterization of “Erasers” for Fatty‐Acid‐Acylated Lysine Residues within Proteins 下载免费PDF全文
Zheng Liu Tangpo Yang Xin Li Tao Peng Prof. Howard C. Hang Prof. Xiang David Li 《Angewandte Chemie (International ed. in English)》2015,54(4):1149-1152
Acylation of proteins with fatty acids is important for the regulation of membrane association, trafficking, subcellular localization, and activity of many cellular proteins. While significant progress has been made in our understanding of the two major forms of protein acylation with fatty acids, N‐myristoylation and S‐palmitoylation, studies of the acylation of lysine residues, within proteins, with fatty acids have lagged behind. Demonstrated here is the use of integrative chemical biology approaches to examine human sirtuins as de‐fatty‐acid acylases in vitro and in cells. Photo‐crosslinking chemistry is used to investigate enzymes which recognize fatty‐acid acylated lysine. Human Sirt2 was identified as a robust lysine de‐fatty‐acid acylase in vitro. The results also show that Sirt2 can regulate the acylation of lysine residues, of proteins, with fatty acids within cells. 相似文献
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Dr. Khanh‐Hy Le Ho Dr. Ismail Hijazi Lucie Rivier Dr. Christelle Gautier Dr. Bruno Jousselme Dr. Gustavo de Miguel Dr. Carlos Romero‐Nieto Prof. Dirk M. Guldi Dr. Benoit Heinrich Dr. Bertrand Donnio Dr. Stéphane Campidelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(34):11374-11381
Herein the synthesis, characterization, and organization of a first‐generation dendritic fulleropyrrolidine bearing two pending porphyrins are reported. Both the dendron and the fullerene derivatives were synthesized by CuI‐catalyzed alkyne–azide cycloaddition (CuAAC). The electron‐donor–acceptor conjugate possesses a shape that allows the formation of supramolecular complexes by encapsulation of C60 within the jaws of the two porphyrins of another molecule. The interactions between the two photoactive units (i.e., C60 and Zn–porphyrin) were confirmed by cyclic voltammetry as well as by steady‐state and time‐resolved spectroscopy. For example, a shift of about 85 mV was found for the first reduction of C60 in the electron‐donor–acceptor conjugate compared with the parent molecules, which indicates that C60 is included in the jaws of the porphyrin. The fulleropyrrolidine compound exhibits a rich polymorphism, which was corroborated by AFM and SEM. In particular, it was found to form supramolecular fibrils when deposited on substrates. The morphology of the fibrils suggests that they are formed by several rows of fullerene–porphyrin complexes. 相似文献
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Emiliano Tamanini Dr. Stephen E. J. Rigby Dr. Majid Motevalli Matthew H. Todd Dr. Michael Watkinson Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(15):3720-3728
Click to detect! Azamacrocyclic complexes with a triazole scorpion ligand may be easily assembled, as shown for a biotin‐functionalised cyclam derivative. Coordination of the triazole to the metal is perturbed by the binding of avidin to the pendant ligand (see scheme). This event can be sensitively detected with EPR and ENDOR spectroscopy, which confirm the loss of the axial triazole nitrogen donor upon avidin binding. This general strategy may have wide applications in imaging and therapeutics.
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Guowei Wang Xiaolan Luo Chao Liu Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(6):2154-2166
Well‐defined ABCD 4‐Miktoarm star‐shaped quarterpolymers of [poly(styrene)‐poly(tert‐butyl acrylate)‐poly(ethylene oxide)‐poly(isoprene)] [star(PS‐PtBA‐PEO‐PI)] were successfully synthesized by the combination of the “click” chemistry and multiple polymerization mechanism. First, the poly(styryl)lithium (PS?Li+) and the poly(isoprene)lithium (PI?Li+) were capped by ethoxyethyl glycidyl ether (EEGE) to form the PS and PI with both an active ω‐hydroxyl group and an ω′‐ethoxyethyl‐protected hydroxyl group, respectively. After these two hydroxyl groups were selectively modified to propargyl and 2‐bromoisobutyryl group for PS, the resulted PS was used as macroinitiator for ATRP of tBA monomer and the diblock copolymer PS‐b‐PtBA with a propargyl group at the junction point was achieved. Then, using the functionalized PI as macroinitiator for ROP of EO monomer and bromoethane as blocking agent, the diblock copolymer PI‐b‐PEO with a protected hydroxyl group at the conjunction point was synthesized. After the hydrolysis, the recovered hydroxyl group of PI‐b‐PEO was modified to bromoacetyl and then azide group successively. Finally, the “click” chemistry between them was proceeded smoothly. The obtained star‐shaped quarterpolymers and intermediates were characterized by 1H NMR, FT‐IR, and SEC in detail. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2154–2166, 2008 相似文献