Saccharide-Dependent Induction of Chiral Helicity in Achiral Synthetic Hydrogen-Bonding Oligomers

Inoûye, Masahiko; Waki, Minoru; Abe, Hajime

doi:10.1021/ja039371g

Cited by 257 publications

(136 citation statements)

References 19 publications

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“…We used the (13,4), (14,5), (15,6), (16,7), and (17,8) SWBNNTs with diameters ranging from 12.0 to 17.3 . The lengths of these SWBNNTs are about 40 .…”

Section: Methodsmentioning

confidence: 99%

“…[5] Recently, the conformational transitions of some chiral molecules have been observed experimentally through encapsulation in synthetic cavities. [6][7][8] In bulk systems, great effort has been invested in this subject for the resolution of chiral molecules. [9][10][11][12][13][14][15][16][17][18][19] The differences in the structure and the spectrum of molecules with different chiralities have been recognized.…”

Section: Introductionmentioning

confidence: 99%

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Size Dependence of Nanoscale Confinement on Chiral Transformation

Wang

Xiu

et al. 2010

Chemistry A European J

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Molecular dynamic simulations of the chiral transition of a difluorobenzo[c]phenanthrene molecule (C(18)H(12)F(2), D molecule) in single-walled boron-nitride nanotubes (SWBNNTs) revealed remarkable effects of the nanoscale confinement. The critical temperature, above which the chiral transition occurs, increases considerably with the nanotube diameter, and the chiral transition frequency decreases almost exponentially with respect to the reciprocal of temperature. The chiral transitions correlate closely with the orientational transformations of the D molecule. Furthermore, the interaction energy barriers between the D molecule and the nanotube for different orientational states can characterize the chiral transition. This implies that the temperature threshold of a chiral transition can be controlled by a suitable nanotube. These findings provide new insights to the effect of nanoscale confinement on molecular chirality.

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“…We used the (13,4), (14,5), (15,6), (16,7), and (17,8) SWBNNTs with diameters ranging from 12.0 to 17.3 . The lengths of these SWBNNTs are about 40 .…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Size Dependence of Nanoscale Confinement on Chiral Transformation

Wang

Xiu

et al. 2010

Chemistry A European J

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“…5). 60 The poly(m-ethynylpyridine)s would normally adopt unfolded conformations because every nitrogen atom in pyridine is mainly located at the opposite sides of the ethynediyl bonds to cancel the dipoles. However, when the polymers meet with a saccharide, transition from the disordered state to the ordered helical state was driven by hydrogen-bonding with saccharides, and the chiral sense of the helices was transferred from the bound saccharides.…”

Section: Foldamers From Oligomers and Polymersmentioning

confidence: 99%

Self‐assembly of supramolecular polymers into tunable helical structures

Kim

Lim

Lee

2008

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:There is growing interest in the design of synthetic molecules that are able to selfassemble into a polymeric chain with compact helical conformations, which is analogous to the folded state of natural proteins. Herein, we highlight supramolecular approach to the formation of helical architectures and their conformational changes driven by external stimuli. Helical organization in synthetic self-assembling systems can be achieved by the various types of noncovalent interactions, which include hydrogen bonding, solvophobic effects, and metal-ligand interactions. Since the external environment can have a large influence on the strength and configuration of noncovalent interactions between the individual components, stimulus-induced alterations in the intramolecular noncovalent interactions can result in dynamic conformational change of the supramolecular helical structure thus, driving significant changes in the properties of the materials. Therefore, these supramolecular helices hold great promise as stimuli-responsive materials.

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“…This observation confused us because octyl b-d-glucopyranoside induced intense CD signals on association with 2, a lipophilic analogue of 1, in less polar solvents. [7] Detailed investigations on this phenomenon elucidated that helix inversion [8] occurs in polymer 1 as a result of anomerization of b-glucose to a-glucose and vice versa (Scheme 2). In other words, each anomer of glucose caused the polymer to bias a single-handed helix in the opposite sense.…”

mentioning

confidence: 99%

Translation of Mutarotation into Induced Circular Dichroism Signals through Helix Inversion of Host Polymers

Waki¹,

Abe²,

Inoûye³

2007

Angew Chem Int Ed

Self Cite

134

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One of the most exciting and challenging topics in molecular recognition is the development of artificial host molecules that recognize saccharides in aqueous protic media through the formation of hydrogen bonds. [1,2] We recently designed and synthesized water-soluble meta-ethynylpyridine polymers such as 1 (Scheme 1) [3] which spontaneously form helical structures in protic media through intramolecular solvophobic interactions. [3,4] This organization forces the pyridine N atoms to be positioned on the inside of the helix. In the resulting pore, saccharides interact with the polymer through the formation of hydrogen bonds between the OH groups of the saccharide and the pyridine N atoms of the polymer, even in 100 % protic media.[5] The association could be clearly detected by the appearance of induced circular dichroism (ICD) [6] signals in the absorptive region of the polymer. However, among the monosaccharides examined in this investigation, glucose exhibited weak ICD effects. This observation confused us because octyl b-d-glucopyranoside induced intense CD signals on association with 2, a lipophilic analogue of 1, in less polar solvents. [7] Detailed investigations on this phenomenon elucidated that helix inversion [8] occurs in polymer 1 as a result of anomerization of b-glucose to a-glucose and vice versa (Scheme 2). In other words, each anomer of glucose caused the polymer to bias a single-handed helix in the opposite sense. Therefore, the ICD effects should be virtually cancelled out by the existence of both the right-and left-handed helices from an equilibrium mixture of a/b-glucose (ca. 1/1). This finding means that real-time information concerning the mutarotation of glucose is translated into ICD signals of the polymer through recognition-induced chirality transfer from the small molecules to the supramolecular architectures.As mentioned above, a mixture of the water-soluble polymer 1 with d-glucose in MeOH/water (10:1) showed only a weak ICD band around 337 nm.[3] We also observed that the ICD effects could be reversed by changing the solvent composition. Figure 1 a shows the CD spectra for 1 with d-glucose in MeOH/water mixtures of various ratios after the solutions had been allowed to stand over 48 h to reach the equilibrium state. A weak negative ICD was observed around 337 nm in a MeOH/water mixture of 10:1. However, the ICD effects weakened when the fraction of water was increased, and almost disappeared in a MeOH/water mixture of 8:1. Further increasing the water fraction (up to MeOH/water 5:1) resulted in positive ICD signals appearing in the same wavelength region instead. In the case of 2 with octyl b-dglucopyranoside, the sign of the ICD effects remained unchanged regardless of the solvents used, although the ellipticity varied. There is a critical difference between dglucose and octyl b-d-glucopyranoside: the former undergoes mutarotation in solutions and the latter does not.[9] Therefore, we speculated that the curious ICD behaviors of 1 may result from the mutarotation of d-glucose, and...

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Saccharide-Dependent Induction of Chiral Helicity in Achiral Synthetic Hydrogen-Bonding Oligomers

Cited by 257 publications

References 19 publications

Size Dependence of Nanoscale Confinement on Chiral Transformation

Size Dependence of Nanoscale Confinement on Chiral Transformation

Self‐assembly of supramolecular polymers into tunable helical structures

Translation of Mutarotation into Induced Circular Dichroism Signals through Helix Inversion of Host Polymers

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