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  • Physics  (13)
  • optically active polymer  (4)
  • chiral stationary phases  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2013-2019 
    ISSN: 0887-624X
    Keywords: asymmetric polymerization ; anionic polymerization ; (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl) methyl methacrylate ; optically active polymer ; helix ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel racemic methacrylate, (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl)-methyl methacrylate1 (2F4F2PyMA), was synthesized and polymerized with chiral complexes of N,N′-diphenylethylenediamine monolithium amide (DPEDA-Li) with (-)-sparteine (Sp), (2S, 3S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane (DDB), and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP) in toluene at -78°C. The monomer showed higher resistance against methanolysis compared with triphenylmethyl methacrylate (TrMA) and several other analogues. In the asymmetric anionic polymerization of 2F4F2PyMA, PMP was found to be a more effective chiral ligand than DDB and Sp and gave quantitatively an optically active polymer with nearly perfect isotacticity. Enantiomer selection was observed in the polymerization of racemic 2F4F2PyMA with the chiral lithium complexes. Chiral recognition ability of the optically active poly(2F4F2PyMA) was examined by an enantioselective adsorption experiment. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2013-2019, 1998
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2721-2728 
    ISSN: 0887-624X
    Keywords: phenyl[bis(2-pyridyl)]methyl methacrylate ; optically active polymer ; solvolysis ; chiral stationary phase ; anionic polymerization ; (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine ; optical resolution ; high performance liquid chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel monomer, phenyl[bis(2-pyridyl)]methyl methacrylate (PB2PyMA), was synthesized. The solvolysis rate of PB2PyMA measured in CDCl3-CD3 OD [1/1 (v/v)] by 1H-NMR spectroscopy at 35°C was much smaller than those of triphenylmethyl methacrylate (TrMA) and diphenyl-2-pyridylmethyl methacrylate (D2PyMA). PB2PyMA was anionically polymerized with the complexes of organolithiums with (-)-sparteine (Sp), (S,S)-(+)-and (R,R)-(-)-2,3-dimethoxy-1,4-bis(dimethylamino)butanes[(+)-and (-) -DDB], and (S)-(+)-1-(2-pyrrolidinylmethyl) pyrrolidine (PMP) in toluene at low temperature. The polymers obtained with Sp and DDB complexes showed low optical activity. PMP complexes, particularly that with N,N′-diphenylethylenediamine monolithium amide, were effective in synthesizing a polymer of high optical rotation ([α]25365 ∼ +1350°) which was comparable to those of poly(TrMA) and poly(D2PyMA) with one-handed helical structure. The optical rotation of poly(PB2PyMA) in a mixture of CHCl3 and 2,2,2-trifluoroethanol (9/1, v/v) slowly decreased with time. Optically active poly(PB2PyMA) coated on macroporous silica gel was able to resolve racemic compounds as a chiral stationary phase for high-performance liquid chromatography. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 309-315 
    ISSN: 0887-624X
    Keywords: polyisocyanate ; asymmetric anionic polymerization ; helix ; optically active polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The asymmetric anionic polymerization of o-, m-, and p-methylphenyl isocyanates, p-methoxyphenyl isocyanate, p-chlorophenyl isocyanate, 2,6- and 3,4-dimethylphenyl isocyanates, and 1-naphthyl isocyanate was carried out using chiral anionic initiators such as the lithium salts of (-) -menthol, (-) -(2-methoxymethyl) pyrrolidine, and (+) -1-(2-pyrrolidinylmethyl) pyrrolidine. Although o-methylphenyl isocyanate gave an insoluble polymer and 2,6-dimethylphenyl isocyanate afforded no polymer, the other monomers gave soluble polymers, which showed optical activity due to the prevailing helicity of the polymer chain induced by chiral initiator residues attached to the α-end of the polymer chain. The molecular mechanics conformational calculation for a tetramer of m-methylphenyl isocyanate supported the helical conformation of the main chain. The optical rotation of the polymers depended significantly on temperature. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 0899-0042
    Keywords: asymmetric polymerization ; stereospecific polymerization ; optically active polymer ; helix ; (+)-tartaric acid ; L-proline ; (+)-(S)-2-(1-pyrrolidinylmethyl)pyrrolidine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of diphenyl-2-pyridylmethyl methacrylate was carried out with the complexes of organolithium compounds with 22 chiral ligands. Helix-sense-selectivity of the polymerization was largely affected by a slight structural difference of chiral ligands. (+)-(S)-2-(1-Pyrrolidinylmethyl)pyrrolidine was the most effective ligand in producing a one-handed helical polymer with narrow molecular weight distribution.
    Additional Material: 3 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 122-124 
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; HPLC ; chiral stationary phases ; cellulose tris(1-phenylethylcarbamate) ; amylose tris(1-phenylethylcarbamate) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 1 (1989), S. 216-222 
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; chiral stationary phases ; cellulose tris(phenylcarbamate) ; amylose tris(3,5-dimethylphenylcarbamate) ; CD spectra ; absolute configuration ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Separation and optical resolution of 6 diastereomers and 25 racemates of β-lactams were examined by HPLC on chiral stationary phases composed of six cellulose and one amylose tris(phenylcarbamate) derivatives. Most β-lactams were optically resolved at least by one of the derivatives. The absolute configuration of β-lactams was estimated by CD spectroscopy.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 3043-3051 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylmethyl methacrylate (TrMA) was polymerized with two types of asymmetric anionic catalyst, lithium (R)-N-(1-phenylethyl)anilide (LiAn) and (-)-sparteine-butyllithium complex (Sp-BuLi), at -78°C. Both catalysts yielded optically active polymers. The polymers obtained with LiAn in toluene and tetrahydrofuran (THF) showed specific rotations [α]20D of from -50° to -90° (in THF). The [α]20D of the polymer obtained with Sp-BuLi in toluene was positive and increased with polymer yield reaching above +300°s, whereas the polymer obtained in THF showed a low [α]20D (ca. +7°). Gel permeation chromatograms of both polymers obtained with LiAn and Sp-BuLi in THF exhibited rather narrow molecular weight distributions, whereas those obtained in toluene showed at least two or three components with markedly different molecular weights. The circular dichroism (CD) spectrum of the polymer obtained with Sp-BuLi showed strong positive peaks at 208 and 232 nm and a weak band at 250-280 nm; the polymer produced with LiAn showed a similar spectrum with opposite sign. The poly(methyl methacrylate)s derived from these poly(TrMA)s were highly isotactic but showed negligible rotations ([α]20D ± 2° in toluene). The polymer of high molecular weight showed clear polarization under a polarizing microscope and the low polymer obtained with LiAn appeared to show flow birefringence in chloroform at room temperature.
    Additional Material: 6 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 1161-1174 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomer reactivity ratios, r1 and r2 were determined in the anionic copolymerizations of methyl methacrylate (MMA, M1) with ethyl (EtMA), isopropyl (i-PrMA), tert-butyl (t-BuMA), benzyl (BzMA), α-methylbenzyl (MBMA), diphenylmethyl (DPMMA), α,α-dimethylbenzyl (DMBMA), and trityl (TrMA) methacrylates (M2) by use of n-BuLi as an initiator in toluene and THF at -78°C. The order of the reactivity of the monomers towards MMA anion was DPMMA 〉 BzMA 〉 MMA 〉 EtMA 〉 MBMA 〉 i-PrMA 〉 t-BuMA 〉 TrMA 〉 DMBMA in toluene and TrMA 〉 BzMA 〉 MMA 〉 DPMMA 〉 EtMA 〉 MBMA 〉 i-PrMA 〉 DMBMA 〉 t-BuMA in THF. Except for the extremely low reactivity of TrMA and DPMMA in toluene due to steric hindrance, the order was explained in terms of the polar effect of the ester groups. A linear relationship was found between log (1/r1) and Taft's σ* values of the ester groups, where the ρ* value was 1.1. The plots of log (1/r1) vs. the 1Ha (cis to the carbonyl) and 13Cß chemical shifts of the monomers were also on straight lines. The polymer obtained in the copolymerization of MMA with TrMA in toluene by n-BuLi at -78°C was a mixture of poly-MMA and a copolymer, suggesting that there exist two kinds of growing centers.
    Additional Material: 10 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 1215-1225 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomer reactivity ratios r1 and r2 were determined in the copolymerizations of methyl methacrylate (MMA, M1) with 1, 1-diphenylethyl (DPEMA), α,α-dimethylbenzyl (DMBMA), tert-butyl (t-BuMA), diphenylmethyl (DPMMA), phenyl (PhMA), and 1-naphthyl (NpMA) methacrylates (M2) in tetrahydrofuran (THF) by azobisisobutyronitrile (AIBN) at 60°C and butyllithium (n-BuLi) at -78°C. The reactivities of the monomers were explained in terms of the polar effect of the ester groups in both copolymerizations. All the copolymers isolated in low yields were converted to PMMA either directly or by copoly(MMA - methacrylic acid) to determine the triad tacticities of the copolymers. Coisotactic parameters σ12 and σ21 were determined by assuming the terminal model statistics. The σ21 values always accorded to the σ21 values within experimental error, and in radical copolymerizations they were between isotactic parameters σ11 and σ22 of the homopolymerizations of MMA and M2 monomers. In anionic copolymerizations, however, the σ12 = σ21 values varied, depending on the M2 monomers. In copolymerization with DPEMA the values were less than both σ11 and σ22 with DMBMA they were between σ11 and σ22, with DPMMA, nearly equal to σ11, and with PhMA and NpMA, greater than both σ11 and σ22. The application of these parameters to copolymerizations performed at high conversion was also investigated.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 2647-2650 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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