Helicity induction on a poly(phenylacetylene) derivative bearing aza‐18‐<i>crown</i>‐6 ether pendants in water

Nonokawa, Ryuji; Yashima, Eiji

doi:10.1002/pola.10634

Cited by 43 publications

(39 citation statements)

References 33 publications

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“…The first example was reported for poly(phenylacetylene) with aza-18-crown-6 (2), in which a macromolecular helicity was induced on the main chain through the host-guest complexation with the perchlorate salts of amino acids [27,28]. For this helicity induction system, an unprecedented sensitivity was observed, that is, the polymer could respond to an extremely small amount of chiral information.…”

Section: Helicity Inductionmentioning

confidence: 99%

New Functional Polymers Using Host–Guest Chemistry

Sakai

Kakuchi

2012

Functional Polymers by Post‐Polymerization Modification

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Section: Helicity Inductionmentioning

confidence: 99%

New Functional Polymers Using Host–Guest Chemistry

Sakai

Kakuchi

2012

Functional Polymers by Post‐Polymerization Modification

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“…In addition, Takeishi et al25 reported that for a helical polyamide consisting of atropisomeric binaphthyl units and crown ether rings, the complex formation of crown ether with metal cation caused a conformational change. Recently, Yashima and coworkers27–29 and we30, 31 accomplished the macromolecular helicity induction of poly(phenylacetylene)s and poly(phenyl isocyanate)s bearing crown ether, respectively. These polymers formed the one‐handed helical structure in the main chain through the host–guest complexation with optically active guests, in which crown ether oriented in the helical array based on the polymer helix axis.…”

Section: Introductionmentioning

confidence: 99%

Chiral discrimination of a helically organized crown ether array parallel to the helix axis of polyisocyanate

Sakai

Otsuka

Satoh

et al. 2005

J. Polym. Sci. A Polym. Chem.

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The asymmetric polymerization of 4′‐isocyanatobenzo‐18‐crown‐6 with the lithium amide of (S)‐(2‐methoxymethyl)pyrrolidine successfully proceeded to afford end‐functionalized poly(4′‐isocyanatobenzo‐18‐crown‐6) with (S)‐(2‐methoxymethyl)pyrrolidine (polymer 2). In the circular dichroism (CD) spectrum of 2, a clear positive Cotton effect was observed in the range of 240–350 nm corresponding to the absorption of the polymer backbone, indicating that 2 partially formed a one‐handed helical structure, which was preserved by the chirality of (S)‐(2‐methoxymethyl)pyrrolidine bonding to the terminal end in 2. In the titration experiments for the CD intensity of 2 in the presence of D‐ and L‐Phe·HClO4 (where Phe is phenylalanine), a small but remarkable difference was observed in the amount of the chiral guest needed for saturation of the CD intensity and in the saturated CD intensity, indicating that the extremely stable, one‐handed helical part should exist in the main chain of 2, which was not inverted even when the unfavorable chiral guest for the predominant helical sense, L‐Phe·HClO4, was added. In addition, helical polymer 2 exhibited a chiral discrimination ability toward racemic guests; that is, the guests were extracted from the aqueous phase into the organic phase with enantiomeric excess. The driving force of the chiral discrimination ability of 2 should certainly be attributed to the one‐handed helical structure in 2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 325–334, 2006

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“…Previous research indicates that chiral ammonium salts have an effect on polymers with flexible main chain structures, such as poly(phenylacetylene) and poly(isocyanate). [17][18][19][20][21][22][23][24][25] In this study, we investigated the effect of adding a chiral ammonium salt to the maleimide polymer with a rigid main chain structure. Because the main chain structure is rigid, there is no space between the bulky N-substituents, including a crown ether unit.…”

Section: Optical Properties Of Polymersmentioning

confidence: 99%

“…Recently, polymers bearing various crown ethers have been investigated. For example, Yashima and co-workers [18][19][20][21][22] and Kakuchi and co-workers [23][24][25][26] reported that poly(phenylacetylene) and poly(isocyanate) bearing an aza crown ether or a benzo crown ether induced a one-handed helical structure upon the addition of chiral alkyl ammonium salts, chiral amino alcohols and chiral amino acids.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and asymmetric polymerization of chiral maleimides bearing an aza crown ether

Azechi

Iwai

Yamabuki

et al. 2011

Polym J

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Chiral N-substituted maleimide derivatives bearing L-phenylalanine-or L-leucine-introduced aza crown ether ((S)-A15C5PAMI, (S)-A15C5LMI) were synthesized from maleic anhydride, corresponding amino acids and aza crown ether, and polymerized with an organometal/chiral ligand. The number-average-molecular weights and the specific optical rotations of the polymers were 700-5600 and À105.81 to À38.31, respectively. The specific optical rotations of all polymers tended to a positive direction, Keywords: amino acid; anionic polymerization; asymmetric polymerization; aza crown ether; maleimide INTRODUCTIONThe synthesis of optically active polymers is interesting from the standpoints of the formation process, stereoregularity and asymmetric functionality. The optical activity of these polymers is dependent on the main chain forming a one-handed helical structure. The main chain structure of these optically active polymers is very important for special functions such as molecular recognition and asymmetric catalysis. To artificially form a one-handed helical structure, it is necessary to synthesize an optically active polymer by asymmetric polymerization. For example, Okamoto and coworkers [1][2][3][4] reported that the polymers obtained from the asymmetric polymerization of methacrylate derivatives bearing bulky substituents showed substantial optical activity on the basis of one-handed helical conformations.N-Substituted maleimides (RMIs) have been well known as a type of attractive monomer that provides optically active polymers through asymmetric anionic polymerization. 5,6 Because the RMI has a 1,2-disubstituted structure, poly(RMI) can be presumed to produce four types of structures: threo-diisotactic, threo-disyndiotactic, erythrodiisotactic and erythro-disyndiotactic. Erythro-diisotactic and erythro-disyndiotactic structures cannot be formed with cis-additional reactions because of steric hindrance among monomeric units due to carbonyl groups in the imide rings. 7 Trans-additional structures, that is, threo-diisotactic and threo-disyndiotactic structures, can be formed during the polymerization of RMI. Threo-disyndiotactic structures show no optical activity because the (S, S)-and (R, R)-configurational pairs exist at equivalent levels in the polymer main chains. Poly(RMI) with a threo-diisotactic structure can show optical activity when one of the asymmetric carbon pairs in the monomer unit exists in excess. Furthermore, the high continuity of the same configurational pair

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Helicity induction on a poly(phenylacetylene) derivative bearing aza‐18‐crown‐6 ether pendants in water

Cited by 43 publications

References 33 publications

New Functional Polymers Using Host–Guest Chemistry

New Functional Polymers Using Host–Guest Chemistry

Chiral discrimination of a helically organized crown ether array parallel to the helix axis of polyisocyanate

Synthesis and asymmetric polymerization of chiral maleimides bearing an aza crown ether

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