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Ivan Huc - One of the best experts on this subject based on the ideXlab platform.
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loading linear arrays of cuii inside Aromatic Amide helices
Angewandte Chemie, 2021Co-Authors: Jinhua Wang, Ivan Huc, Victor Maurizot, Barbara Wicher, Alejandro Mendezardoy, Gilles Pecastaings, Thierry Buffeteau, Dario M BassaniAbstract:The very stable helices of 8-amino-2-quinolinecarboxylic acid oligoAmides are shown to uptake CuII ions in their cavity through deprotonation of their Amide functions with minimal alteration of their shape, unlike most metallo-organic structures which generally differ from their organic precursors. The outcome is the formation of intramolecular linear arrays of a defined number of CuII centers (up to sixteen in this study) at a 3 A distance, forming a molecular mimic of a metal wire completely surrounded by an organic sheath. The helices pack in the solid state so that the arrays of CuII extend intermolecularly. Conductive-AFM and cyclic voltammetry suggest that electrons are transported throughout the metal-loaded helices in contrast with hole transport observed for analogous foldamers devoid of metal ions.
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loading linear arrays of cu ii inside Aromatic Amide helices
Angewandte Chemie, 2021Co-Authors: Jinhua Wang, Victor Maurizot, Barbara Wicher, Alejandro Mendezardoy, Gilles Pecastaings, Thierry Buffeteau, Dario M Bassani, Ivan HucAbstract:The very stable helices of 8-amino-2-quinolinecar-boxylic acid oligoAmides are shown to uptake CuIIions in theircavity through deprotonation of their Amide functions with minimal alteration of their shape, unlike most metallo-organicstructures which generally differ from their organic precursors.The outcome is the formation of intramolecular linear arrays of a defined number of CuIIcenters (up to sixteen in this study)at a 3 distance, forming a molecular mimic of a metal wirecompletely surrounded by an organic sheath. The helices packin the solid state so that the arrays of CuIIextend intermolecularly. Conductive-AFM and cyclic voltammetry suggest thatelectrons are transported throughout the metal-loaded helices in contrast with hole transport observed for analogous foldamers devoid of metal ions.
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single molecule mechanics of synthetic Aromatic Amide helices ultrafast and robust non dissipative winding
Chem, 2021Co-Authors: Ivan Huc, Victor Maurizot, Floriane Devaux, Damien Sluysmans, Evangelos Bakalis, Francesco Zerbetto, Annesophie DuwezAbstract:Summary Because of proteins’ many degrees of conformational freedom, programming protein folding dynamics, overall elasticity, and motor functions remains an elusive objective. Instead, smaller and simpler objects, such as synthetic foldamers, may be amenable to design. However, little is known about their mechanical performance. Here, we show that reducing molecular size may not compromise mechanical properties. We report that helical Aromatic oligoAmides as small as 1 nm possess outstanding elasticity and outperform most natural helices. Using single-molecule force spectroscopy, we characterize their folding trajectories and intermediate states. We show that they cooperatively and reversibly unwind at high forces. They extend up to 3.8 times their original length and rewind against considerable forces on a timescale of 10 μs. Pulling and relaxing cycles follow the same trace up to a very high loading rate, indicating that the mechanical energy accumulated during the stretching does not dissipate and is immediately reusable.
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hybrid sequences that express both Aromatic Amide and α peptidic folding features
ChemPlusChem, 2020Co-Authors: P K Mandal, Ivan Huc, Brice KauffmannAbstract:Foldamers combining aliphatic and Aromatic main-chain units often produce atypical structures that cannot easily be accessed from purely Aromatic or aliphatic sequences. We report solid-state evidence that sequences comprising α-amino acids and quinoline-based monomers adopt conformations that combine the folding propensities of both components. Foldamers 2 and 3 having an XQQ repeat motif (X=α-amino acid, Q=quinoline) were synthesized. Crystals of 2 (X=Phe, Q with an anionic side chain) obtained from water revealed an Aromatic helix where Amide groups belonging to the α-amino acids created a hydrogen-bond array typical of peptidic helices. Crystals of 3 (X=Ser, Q with a lipophilic side chain) obtained from organic solvents revealed a helix-turn-helix structure in which α-amino acid side chains interfere with main-chain hydrogen bonding. High sequence-dependency of the conformation is typical of peptides but is shown here to include Aromatic folding features.
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frustrated helicity joining the diverging ends of a stable Aromatic Amide helix to form a fluxional macrocycle
Angewandte Chemie, 2018Co-Authors: Vojislava Pophristic, Zhiwei Liu, Ko Urushibara, Yann Ferrand, Hyuma Masu, Aya Tanatani, Ivan HucAbstract:Macrocyclization of a stable two-turn helical Aromatic pentAmide, that is, an object with diverging ends that are not prone to cyclization, was made possible by the transient introduction of disruptors of helicity in the form of acid-labile dimethoxybenzyl tertiary Amide substituents. After removal of the helicity disruptors, NMR, X-ray crystallography, and computational studies show that the macrocycle possesses a strained structure that tries to gain as high a helical content as possible despite being cyclic. Two points of disruption of helicity remain, in particular a cis Amide bond. This point of disruption of helicity can propagate along the cycle in a fluxional manner according to defined trajectories to produce ten degenerate conformations.
Zhanjiang Zheng - One of the best experts on this subject based on the ideXlab platform.
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asymmetric michael addition of aldimino esters with chalcones catalyzed by silver xing phos mechanism oriented divergent synthesis of chiral pyrrolines
Chemistry: A European Journal, 2016Co-Authors: Xingfeng Bai, Zhanjiang Zheng, Chungu Xia, Yuming CuiAbstract:The mechanism-oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, Aromatic Amide-derived nonbiarylatropisomer/silver (silver/Xing-Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis-Δ(1)-pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing-Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)-pyrrolines, in which an epimerization of the cis-Δ(1)-pyrrolines to the trans-isomers during was revealed.
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Aromatic Amide derived nonbiaryl atropisomer as highly efficient ligand for asymmetric silver catalyzed 3 2 cycloaddition
ACS Catalysis, 2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters.
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Aromatic-Amide-Derived Nonbiaryl Atropisomer as Highly Efficient Ligand for Asymmetric Silver-Catalyzed [3 + 2] Cycloaddition
2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters
Xingfeng Bai - One of the best experts on this subject based on the ideXlab platform.
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asymmetric michael addition of aldimino esters with chalcones catalyzed by silver xing phos mechanism oriented divergent synthesis of chiral pyrrolines
Chemistry: A European Journal, 2016Co-Authors: Xingfeng Bai, Zhanjiang Zheng, Chungu Xia, Yuming CuiAbstract:The mechanism-oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, Aromatic Amide-derived nonbiarylatropisomer/silver (silver/Xing-Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis-Δ(1)-pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing-Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)-pyrrolines, in which an epimerization of the cis-Δ(1)-pyrrolines to the trans-isomers during was revealed.
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Aromatic Amide derived nonbiaryl atropisomer as highly efficient ligand for asymmetric silver catalyzed 3 2 cycloaddition
ACS Catalysis, 2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters.
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Aromatic-Amide-Derived Nonbiaryl Atropisomer as Highly Efficient Ligand for Asymmetric Silver-Catalyzed [3 + 2] Cycloaddition
2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters
Chungu Xia - One of the best experts on this subject based on the ideXlab platform.
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asymmetric michael addition of aldimino esters with chalcones catalyzed by silver xing phos mechanism oriented divergent synthesis of chiral pyrrolines
Chemistry: A European Journal, 2016Co-Authors: Xingfeng Bai, Zhanjiang Zheng, Chungu Xia, Yuming CuiAbstract:The mechanism-oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, Aromatic Amide-derived nonbiarylatropisomer/silver (silver/Xing-Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis-Δ(1)-pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing-Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)-pyrrolines, in which an epimerization of the cis-Δ(1)-pyrrolines to the trans-isomers during was revealed.
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Aromatic Amide derived nonbiaryl atropisomer as highly efficient ligand for asymmetric silver catalyzed 3 2 cycloaddition
ACS Catalysis, 2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters.
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Aromatic-Amide-Derived Nonbiaryl Atropisomer as Highly Efficient Ligand for Asymmetric Silver-Catalyzed [3 + 2] Cycloaddition
2015Co-Authors: Xingfeng Bai, Chungu Xia, Zhanjiang ZhengAbstract:In this work, we have successfully determined that the Aromatic Amide-derived nonbiaryl atropisomer/silver complex (silver-Xing-Phos) is an effective catalyst system for the solvent-dependent exo-selective cycloaddition of glycine aldimino esters with chalcones or less-reactive methyl cinnamates to give the corresponding chalcone- or cinnamate-derived pyrrolidines with multiple stereogenic centers in good yields and high diastereoselectivities as well as excellent enantioselectivities. Remarkably, it is the first example of highly enantioselective silver-catalyzed [3 + 2] cycloaddition of methyl cinnamates with glycine aldimino esters
Xikui Jiang - One of the best experts on this subject based on the ideXlab platform.
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folding of Aromatic Amide based oligomers induced by benzene 1 3 5 tricarboxylate anion in dmso
Journal of Organic Chemistry, 2009Co-Authors: Guitao Wang, Xin Zhao, Xikui JiangAbstract:In this paper, we describe the folding of a series of linear arylAmide oligomers in DMSO that is induced by benzene-1,3,5-tricarboxylate anion. The oligomers are comprised of naphthalene-2,7-diamine and 1,3,5-benzenetricarboxylic acid segments with two (tert-butoxycarbonylamino) groups at the ends and two to four hydrophilic N,N-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)amino groups at one side of the backbones. (2D NOESY) 1H NMR, fluorescence and UV−vis studies indicate that the oligomers do not adopt defined conformations in DMSO but fold into compact structures in the presence of the anion. It is revealed that the folded conformation is induced by intermolecular hydrogen bonds between the Amide and Aromatic hydrogen atoms of the oligomers and the oxygen atoms of the anion. 1H NMR and UV−vis titrations support a 1:1 binding stoichiometry, and the associated constants are determined, which are found to increase with the elongation of the oligomers.
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self assembly of vesicles from amphiphilic Aromatic Amide based oligomers
Langmuir, 2009Co-Authors: Guitao Wang, Xin Zhao, Xikui JiangAbstract:A novel class of linear arylAmide oligomers has been designed and synthesized from naphthalene-2,7-diamine and benzene-1,3,5-tricarboxylic acid segments. The molecules carry two (tert-butoxycarbonylamino) groups at the ends and one to three hydrophilic N,N-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)amino groups at one side of the backbone. The oligomers self-assembled into vesicular structures in methanol as a result of ordered stacking of the oligomeric Amide backbones, which were evidenced by SEM, AFM, TEM, and fluorescent micrography experiments. It was also found that the tert-butoxycarbonylamino groups at the ends played an important role in promoting the ordered stacking of the backbones. Structural factors that affected the self-assembly of the oligomers were investigated. A two-layer model that was supported by TEM has been proposed for the formation of the vesicular structures, which was driven by both the hydrogen bonding and Aromatic stacking.
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hydrogen bonding induced Aromatic oligoAmide foldamers as spherand analogues to accelerate the hydrolysis of nitro substituted anisole in aqueous media
Journal of Organic Chemistry, 2007Co-Authors: Kuiling Ding, Xikui JiangAbstract:Four intramolecular hydrogen bonding-driven Aromatic Amide foldamers 2−5 have been designed and synthesized in which a 2-methoxy-3-nitrobenzAmide unit was incorporated at the end of the backbone. Kinetic studies in dioxane−water (4:1, v/v) at 60−90 °C have revealed that the folded backbone of the oligomers was, like the rigidified spherand, able to complex Li+, Na+, and K+ and, consequently, accelerated the hydrolysis of the nitro-appended anisole unit of the foldamers. Generally, longer foldamers displayed an increased accelerating effect, and LiOH displayed the highest reactivity probably due to the most efficient complexation by the folded oligomers. Addition of excessive potassium chloride substantially reduced the complexing interaction, and the hydrolysis of the longer oligomers became slower than that of the shorter ones due to an increased steric effect. The results indicate that, even in a hot aqueous medium of high polarity, intramolecular hydrogen bonding is still able to induce structurally ma...