- Patterned recognition of amines and ammonium ions by a stimuli-responsive foldamer-based hexameric oligophenol host
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A stimuli-responsive hexameric oligophenol host undergoes amine-induced co-operative folding from a more fluorescent, more linear structure into less fluorescent, more curved or helically folded states, enabling easy identification and classification of the bound amine guests. The Royal Society of Chemistry 2013.
- Sun, Chang,Ren, Changliang,Wei, Yuchen,Qin, Bo,Zeng, Huaqiang
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supporting information
p. 5307 - 5309
(2013/06/27)
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- Synthesis, structural investigations, hydrogen-deuterium exchange studies, and molecular modeling of conformationally stablilized aromatic oligoamides
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Biasing the conformational preferences of aromatic oligoamides by internally placing intramolecular hydrogen bonds has led to a series of stably folded molecular strands. This article presents the results from extensive solid-state, solution, and computational studies on these folding oligomers. Depending on its backbone length, an oligoamide adopts a crescent or helical conformation. Surprisingly, despite the highly repetitive nature of the backbone, the internally placed, otherwise very similar intramolecular hydrogen bonds showed significantly different stabilities as demonstrated by hydrogen-deuterium exchange data. It was also observed that the hydrogen-bonding strength can be tuned by adjusting the substituents attached to the exterior of the aromatic backbones. Examining the amide hydrogen-deuterium exchange rates of trimers revealed that a six-membered hydrogen bond nearing the ester end is the weakest among all the four intramolecular hydrogen bonds of a molecule. This observation was verified by ab initio quantum mechanical calculations at the level of B3LYP/6-31G. Such a "weak point" creates the "battle of the bulge" where backbone twisting is centered, which is consistently observed in the solid-state structures of the four trimer molecules studied. In the solid state, the oligomers assemble into interesting one-dimensional structures. A pronounced columnar packing of short oligomers (i.e., dimers, trimers, and tetramer) and channel-like, potentially ion-conducting stacks of longer oligomers (i.e., tetramer, pentamer, and hexamer) were observed.
- Yan, Yan,Qin, Bo,Ren, Changliang,Yip, Yeow Kwan,Ye, Ruijuan,Zeng, Huaqiang,Chen, Xiuying,Su, Haibin,Zhang, Dawei
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supporting information; experimental part
p. 5869 - 5879
(2010/07/13)
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- Persistently folded circular aromatic amide pentamers containing modularly tunable cation-binding cavities with high ion selectivity
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In this work, we illustrated a novel design strategy that allows systematically tunable interior properties (effective cavity size, steric crowdedness, and hydrophobicity) contained within a novel class of shape-persistent aromatic pentamers to take place on a scale below 3 A. Such finely tunable structural features are complimented by experimentally observable functional variations in ion-binding potential. Results of the selective, differential binding affinities of three circular pentamers for Li+, Na+, K+, Rb+, and Cs +, substantiated by metal-containing crystal structures and computational modeling, are detailed.
- Qin, Bo,Ren, Changliang,Ye, Ruijuan,Sun, Chang,Chiad, Khalid,Chen, Xiuying,Li, Zhao,Xue, Feng,Su, Haibin,Chass, Gregory A.,Zeng, Huaqiang
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supporting information; experimental part
p. 9564 - 9566
(2010/09/03)
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- Helical organization in foldable aromatic oligoamides by a continuous hydrogen-bonding network
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Introduction of a continuous internal hydrogen-bonding network suppressed the conformational flexibility of a series of oligoaromatic foldamers with a lengthened backbone. The helical ordering over up to six aromatic repeating units was established in solution by a 2D NOESY study and in the solid state by an X-ray diffraction method. Computational molecular modeling further corroborates the experimentally observed helical propagation in this class of foldable molecular strands.
- Yan, Yan,Qin, Bo,Shu, Yingying,Chen, Xiuying,Yip, Yeow Kwan,Zhang, Dawei,Su, Haibin,Zeng, Huaqiang
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supporting information; experimental part
p. 1201 - 1204
(2009/08/07)
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- Crystallographic evidence of an unusual, pentagon-shaped folding pattern in a circular aromatic pentamer
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(Figure Presented) Introduction of a continuous hydrogen-bonding network suppressed the conformational flexibility of an oligomeric backbone. Cyclization of a rigidified, suitably sized oligomer led to a circular aromatic pentamer. Its crystal structure d
- Qin, Bo,Chen, Xiuying,Fang, Xiao,Shu, Yingying,Yip, Yeow Kwan,Yan, Yan,Pan, Siyan,Ong, Wei Qiang,Ren, Changliang,Su, Haibin,Zeng, Huaqiang
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supporting information; experimental part
p. 5127 - 5130
(2009/05/30)
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