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  • 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.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1995-1997 
    ISSN: 0887-624X
    Keywords: Chemistry ; 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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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1965-1971 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neodymium tris(2-ethylhexylphosphonate)-triisobutylaluminum-water system was investigated as a catalyst in ethylene oxide and propylene oxide copolymerization. Random copolymers of ethylene oxide and propylene oxide were obtained with high yield and high molecular weight in a short reaction time. The reactivity ratios of r1(EO) = 1.60 ± 0.04, r2(PO) = 0.45 ± 0.02 were determined. It was found that poly(propylene oxide) prepared with this catalyst system could initiate additional propylene oxide or ethylene oxide to form poly(propylene oxide) with higher molecular weight or propylene oxide-ethylene oxide diblock copolymer. The microstructures of copolymers were studied by 13C-NMR spectroscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solution behavior of the single-stranded CCAAT-containing octamer 1, d(AGCCAATA), that comprises part of the nuclear factor I (NF-I) recognition site at the origin of replication of human adenovirus has been studied by nmr spectroscopy at 500 and 600 MHz. Proton resonance assignments for 1 were aided by selective 13C enrichment at C1′ of A1 or A5. High-resolution 13C-1H heteronuclear multiple-bond coherence spectra of the 13C-labeled oligomers permitted the selective detection of furanosyl ring protons within each labeled residue due to short- and long-range 13C-1H couplings to the enriched C1′. The resulting assignments provided firm starting points in the interpretation of double quantum filtered correlated spectra, yielding information supplemented by total correlated spectroscopy (TOCSY) and rotating frame nuclear Overhauser effect spectroscopic data to completely assign the 1H-nmr spectrum of 1 and extract 3JHH values for furanose con-formational analysis. Several 13C-1H spin-coupling constants within the 13C-enriched A1 or A5 residues were measured from cross-peak shifts in TOCSY spectra, and their signs determined by inspection of the relative orientations of these shifts. 1H-2-H and 13C-1H spin-couplings both indicate a preference (〉 75%) for south (C2′-endo) conformations by the furanosyl rings of 1. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1683-1689 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase behavior and thermally induced phase separation in blends of poly{styrene-co-[p-(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl)ethyl-α-methylstyrene]} (PS(OH)) and a thermotropic liquid crystalline polymer (LCP) were studied by optical microscopy (OM), infrared spectroscopy (IR) and time-resolved light scattering (TRLS). PS(OH) contains strong proton-donating groups  - C(CF3)2OH, and the LCP is poly[p-(tert-butyl)phenylene fumarate] (PBPF), which is soluble in common solvents. For blends of PS(OH)/PBPF, the miscible region was found only at high PBPF compositions and low temperature due to intermolecular hydrogen bonding between  - C(CF3)2OH groups of PS(OH) and the phenolic OH end-groups of PBPF according to IR. The PS(OH)/PBPF blend undergoes phase separation via spinodal decomposition (SD) during isothermal annealing in the two-phase regime of phase diagram. The SD yielded unique Vv and Hv scattering patterns, which can be attributed to regular periodic phase-separated structures composed of an anisotropic phase and an isotropic phase. Preliminary studies on the SD process by TRLS showed that the phase separation spontaneously occurs at a certain time, that might be associated with the presence of the LCP.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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