Induced Helix of an Aliphatic Polyacetylene Detected by Circular Dichroism

Yashima, Eiji; Goto, Hidetoshi

doi:10.1295/polymj.30.69

Cited by 32 publications

(21 citation statements)

References 18 publications

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“…In fact, similar helicity induction in the presence of chiral molecules capable of noncovalently interacting with the polymer×s functional groups was achieved for aliphatic polyacetylenes (10,11), [25] polyphosphazene (12), [26] polyisocyanate (13), [27] polyguanidine (14), [28] and polyisocyanide (15) [29] by our group or others. [33] Inai et al took advantage of the helicity induction concept combined with the structural feature of an achiral oligopeptide (16) as a template to induce a predominantly one-handed helix by chiral carboxylic acids.…”

Section: Chirality Sensing By Supramolecular Systemssupporting

confidence: 67%

Detection and Amplification of Chirality by Helical Polymers

Yashima

Maeda

Nishimura

2003

Chemistry A European J

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534

302

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A unique feature of synthetic helical polymers for the detection and amplification of chirality is briefly described in this article. In sharp contrast to host-guest and supramolecular systems that use small synthetic receptor molecules, chirality can be significantly amplified in a helical polymer, such as poly(phenylacetylene)s with functional pendants, which enable the detection of a tiny imbalance in biologically important chiral molecules through a noncovalent bonding interaction with high cooperativity. The rational design of polymeric receptors can be possible by using chromophoric helical polymers combined with functional groups as the pendants, which target particular chiral guest molecules for developing a highly efficient chirality-sensing system. The chirality sensing of other small molecular and supramolecular systems is also briefly described for comparison.

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Section: Chirality Sensing By Supramolecular Systemssupporting

confidence: 67%

Detection and Amplification of Chirality by Helical Polymers

Yashima

Maeda

Nishimura

2003

Chemistry A European J

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534

302

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“…In sharp contrast to the similar helicity induction and memory of poly(phenylacetylene)s bearing carboxy and phosphonic acid residues as the pendants, the presence of the common salt of the chiral amines was required for the effective helicity induction and the memory of poly-1 in DMSO due to the highly acidic sulfonate groups of poly-1 which favorably dissociate into free ions in DMSO in the absence of common salts. The present results indicate that a similar helicity induction and subsequent memory may be possible for other dynamic helical polymers [53][54][55][56][57][58][59][60][61] including polyacetylenes [62][63][64][65][66][67][68][69] bearing acidic or basic functional groups by the precise control of their ion pair formation and dissociation into free ions in solutions, respectively.…”

Section: Resultssupporting

confidence: 57%

Helicity Induction on a Poly(phenylacetylene) Derivative Bearing a Sulfonic Acid Pendant with Chiral Amines and Memory of the Macromolecular Helicity in Dimethyl Sulfoxide

Hasegawa

Maeda

Ishiguro

et al. 2006

Polym J

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ABSTRACT:A stereoregular poly(phenylacetylene) derivative bearing a sulfonic acid residue (poly-1) as the pendant was found to form a predominantly one-handed helix upon complexation with various chiral amines through noncovalent acid-base interactions in dimethyl sulfoxide (DMSO). In sharp contrast to analogous poly(phenylacetylene)s bearing relatively weak carboxy and phosphonic acid residues as the pendants, the poly-1-amine complexes exhibited a weak induced circular dichroism (ICD) in the UV-visible region of the polymer backbone. However, in the presence of a strong acid, such as p-toluenesulfonic acid (TosOH), the ICD intensity significantly increased, resulting from a favorable ion pair formation between the sulfonic acid residues of the poly-1 and chiral amines, leading to an increase in the helical sense excess of poly-1. Moreover, the macromolecular helicity of poly-1 induced by chiral amines in the presence of TosOH was ''memorized'' after the chiral amines and their salts were completely removed and replaced with an achiral diamine, i.e., ethylene diamine, in DMSO, while no memory effect was observed for a helical poly-1 induced by the same chiral amines in the absence of TosOH.

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“…The stereoregularities of all the polymers were rich in cis-transoid judging from 1 H NMR spectroscopy ( Figure S1). 17,[20][21][22][23][24][25][26][27] Figure 1 shows the CD and absorption spectra of poly-3 and poly-4 in dimethyl sulfoxide (DMSO) containing a small amount of acetic acid, which was used due to the solubility problem of these polymers in DMSO. Poly-3 and poly-4 showed a difference in their CD and absorption spectral patterns because of the methylene linker of poly-4 that likely reduced the -conjugated length of the polymer.…”

Section: Resultsmentioning

confidence: 99%

“…Here we report an alternative method for preparing optically active helical poly(phenylacetylene)s [16][17][18][19][20][21][22][23] based on the helicity induction [16][17][18][24][25][26][27] on optically inactive poly(phenylacetylene)s bearing azide pendant groups (poly-1 and poly-2) by the click polymer reaction using chiral acetylenes (Scheme 1). We anticipated that a preferred-handed helical structure could be induced in the optically inactive poly-1 and poly-2 through the covalent bonding of optically active substituents after the click polymer reaction, which could be easily detected by circular dichroism (CD) spectroscopy, and that this approach might be applicable for developing a facile system to sense the chirality of chiral acetylenes.…”

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confidence: 99%