Preparation and helical folding of aromatic polyamides

Cao, Jianxin; Kline, Mark D.; Chen, Zhongzhu; Luan, Bao; Lv, Menglan; Zhang, Wenrui; Lian, Chunxia; Wang, Qiwei; Huang, Qingfei; Wei, Xiang; Deng, Jingen; Zhu, Jin; Gong, Bing

doi:10.1039/c2cc35886g

Cited by 25 publications

(24 citation statements)

References 54 publications

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“…All the aromatic units of polymer P5 are hydrogen bonded, which enables a rigid helical conformation. Since solvophobically driven intramolecular aromatic stacking is also a driving force for the formation of helical conformations for long aromatic sequences, to exploit the efficiency of this driving force for the aromatic amide sequences, Zhu and Gong and co‐workers prepared polymers P10a ‐ c from the coupling reactions of 8 and 9 (Scheme ) . The two alkoxyl groups on the isophthalamide units form stable intramolecular six‐membered R'O−H⋅⋅⋅N hydrogen bonding, while the 3,5‐diaminobenzamide units can only form intermolecular cross‐amide hydrogen bonding.…”

Section: Polymeric Aromatic Amide‐based Tubular Helicesmentioning

confidence: 99%

Section: Polymeric Aromatic Amide‐based Tubular Helicesmentioning

confidence: 99%

“…In contrast, polymeric analogues are more attractive because they not only enable the formation of long tubular helices (Figure ) but also can be prepared from one‐pot reactions of readily available monomers. In this context, we and other groups have developed aromatic amide‐, hydrazide‐, and urea‐based polymeric backbones that can be driven by intramolecular hydrogen bonding, solvophobicity, or guest‐binding induction to form dynamic tubular helices. This article summarizes the advances for the generation of this family of tubular macromolecular helices, their structural characterization, guest encapsulation, and one‐handedness control.…”

Section: Introductionmentioning

confidence: 99%

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Polymeric Tubular Aromatic Amide Helices

Zhang

Wang

2017

Macromol. Rapid Commun.

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Conjugated polymers may be induced by intra- and/or intermolecular non-covalent forces to fold into helical conformations. Helices formed by aromatic amide, hydrazide, and urea polymers possess a well-organized cavity and depth, which is defined by their degree of polymerization. Driving forces may be intramolecular hydrogen bonding and/or solvophobicity, or guest induction. The resulting long helices represent a new class of unimacromolecular dynamic tubular architectures that exhibit unique properties or functions in, for example, molecular recognition, chirality transfer, and ion transporting. The recent advances are highlighted here.

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Section: Polymeric Aromatic Amide‐based Tubular Helicesmentioning

confidence: 99%

Section: Polymeric Aromatic Amide‐based Tubular Helicesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polymeric Tubular Aromatic Amide Helices

Zhang

Wang

2017

Macromol. Rapid Commun.

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“…The low yields of the coupling steps however limited the number of coupled amino acids to 21, making the creation of a helix with more than one helical turn impossible . To obtain higher molecular weights, an approach via polycondensation of meta ‐diamines and meta ‐diacid chlorides was recently described by the Gong group . The formation of macrocycles could be observed because of the preorganizational effect of the rigid, shape‐persistent backbone.…”

Section: Introductionmentioning

confidence: 99%

Toward large tubular helices based on the polymerization of tri(benzamide)s

Schulze

Kilbinger

2016

J. Polym. Sci. Part A: Polym. Chem.

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Herein we present the synthesis and polycondensation of mono-and di-N-protected, bis-substituted tri(benzamide)s with the aim to create large, tubular helices. We synthesized 2,4-dimethoxy and 2,5-bis-TEGylated aminobenzoic acid derivatives as bent and linear monomers and introduced p-methoxybenzyl (PMB) amide protecting groups to the oligobenzamide backbone. An iterative coupling strategy allowed for sequence control, giving rise to oligomers consisting of one bent and two linear monomers. The resulting meta-parapara-linked aromatic trimers carried either one or two PMBprotecting groups. With high organosolubility and flexibility, this synthetic strategy generated suitable precursors for subsequent polycondensation reactions. After polymerization, treatment with acid triggered the cleavage of the N-protecting groups. We hypothesize that the hydrogen bonding pattern generated along the polyaramide backbone could lead to the formation of a helical polymer. A drastic change in hydrodynamic volume was observed by gel permeation chromatography and dissolution in a chiral solvent lead to the observation of a circular dichroism signal for this polymer. The results of the polycondensations of N-protected oligobenzamides are reported herein. The formation of macrocycles as well as polymers could also be observed, giving a highly interesting insight into the underlying mechanism of the polycondensation of flexible, oligobenzamide-based oligomers.

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“…In a similar way, Cao and coworkers [159] prepared folded aromatic polyamides with partially rigidified backbones by repetitive precipitation (Scheme 43, P70). Fractions of high molecular masses and low dispersity were obtained, adopting a hollow helical conformation that is stabilized by intramolecular H-bonding interactions between side chains.…”

Section: Miscellaneousmentioning

confidence: 99%

Functional Aromatic Polyamides

et al. 2017

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Abstract:We describe herein the state of the art following the last 8 years of research into aromatic polyamides, wholly aromatic polyamides or aramids. These polymers belong to the family of high performance materials because of their exceptional thermal and mechanical behavior. Commercially, they have been transformed into fibers mainly for production of advanced composites, paper, and cut and fire protective garments. Huge research efforts have been carried out to take advantage of the mentioned characteristics in advanced fields related to transport applications, optically active materials, electroactive materials, smart materials, or materials with even better mechanical and thermal behavior.

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Preparation and helical folding of aromatic polyamides

Abstract: Long aromatic polyamide chains are prepared from the corresponding monomers. The resultant polymer adopts a hollow helical conformation that is stabilized by intramolecular H-bonding interaction between side chains.

Cited by 25 publications

References 54 publications

Polymeric Tubular Aromatic Amide Helices

Polymeric Tubular Aromatic Amide Helices

Toward large tubular helices based on the polymerization of tri(benzamide)s

Functional Aromatic Polyamides

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