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Volumn 112, Issue 50, 2008, Pages 19793-19796

Direct structural understanding of a topochemical solid state photopolymerization reaction

Author keywords

[No Author keywords available]

Indexed keywords

EXPERIMENTAL TECHNIQUES; POLY-CRYSTALLINE; POLYMER PHASE; POWDER X-RAY DIFFRACTIONS; SOLID-STATE POLYMERIZATIONS; STRUCTURAL CHARACTERIZATIONS; STRUCTURE DETERMINATIONS; STRUCTURE OF THE POLYMERS; STRUCTURE SOLUTIONS;

EID: 61349160446     PISSN: 19327447     EISSN: 19327455     Source Type: Journal    
DOI: 10.1021/jp808254f     Document Type: Article
Times cited : (63)

References (51)
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    • (d) Thomas, J. M. Nature 1981, 289, 633.
    • (1981) Nature , vol.289 , pp. 633
    • Thomas, J.M.1
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    • David, W. I. F, Shankland, K, McCusker, L. B, Baerlocher, C, Eds, OUP/IUCr
    • (f) David, W. I. F.; Shankland, K.; McCusker, L. B.; Baerlocher, C., Eds. Structure Determination from Powder Diffraction Data, OUP/IUCr, 2002.
    • (2002) Structure Determination from Powder Diffraction Data
  • 29
    • 61349199019 scopus 로고    scopus 로고
    • We note that, as the structure of the monomer phase is known, structure determination of the polymer phase should still be feasible if the powder sample comprised a mixture of monomer and polymer phases. However, structure determination should clearly be more straightforward if the powder sample is a monophasic sample of the polymer phase
    • We note that, as the structure of the monomer phase is known, structure determination of the polymer phase should still be feasible if the powder sample comprised a mixture of monomer and polymer phases. However, structure determination should clearly be more straightforward if the powder sample is a monophasic sample of the polymer phase.
  • 32
    • 61349172591 scopus 로고    scopus 로고
    • From a survey of the Cambridge Structural Database (version 5.29, November, 2007).
    • From a survey of the Cambridge Structural Database (version 5.29, November, 2007).
  • 34
    • 61349145064 scopus 로고    scopus 로고
    • The polymerization reaction was carried out by UV irradiation of a polycrystalline sample of DSP (ca. 0.5 g) in a vessel of 2.5 cm diameter [Oriel ultrahigh-pressure 200 W Hg(Xe) UV lamp; CVI Technical Optics 385 nm filter; current, 2 A; sample-to-lamp distance, ca. 13 cm, The polycrystalline sample was occasionally subjected to manual stirring to minimize the chance that different crystallites (e.g, those originally at the top and bottom of the sample) would receive significantly different amounts of incident radiation within the total duration of the experiment. A total of 45 h of irradiation time under these conditions was sufficient to produce a sample for which the powder X-ray diffraction pattern was characteristic of the polymer phase, with no detectable peaks characteristic of the monomer phase. For shorter irradiation times e.g, 20 h, powder X-ray diffraction indicated that the product was predominantly the polymer phase but with some residual peaks due to the
    • The polymerization reaction was carried out by UV irradiation of a polycrystalline sample of DSP (ca. 0.5 g) in a vessel of 2.5 cm diameter [Oriel ultrahigh-pressure 200 W Hg(Xe) UV lamp; CVI Technical Optics 385 nm filter; current, 2 A; sample-to-lamp distance, ca. 13 cm]. The polycrystalline sample was occasionally subjected to manual "stirring" to minimize the chance that different crystallites (e.g., those originally at the top and bottom of the sample) would receive significantly different amounts of incident radiation within the total duration of the experiment. A total of 45 h of irradiation time under these conditions was sufficient to produce a sample for which the powder X-ray diffraction pattern was characteristic of the polymer phase, with no detectable peaks characteristic of the monomer phase. For shorter irradiation times (e.g., 20 h), powder X-ray diffraction indicated that the product was predominantly the polymer phase but with some residual peaks due to the monomer phase. In such cases, a pure sample of the polymer phase could be obtained by washing the sample with acetone. The powder X-ray diffraction pattern of the material after washing was identical to the powder X-ray diffraction pattern of the material obtained after long (45 h) irradiation time (i.e., pure polymer phase).
  • 35
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    • High-quality powder X-ray diffraction data for use in the structure determination of the polymer phase were recorded at ambient temperature in transmission mode on a Bruker D8 diffractometer [CuKα, Ge-monochromated; linear position-sensitive detector covering 12° in 2θ 2θ range, 5°-70° step size, 0.017° data collection time, 12 h; foil sample holder
    • α, Ge-monochromated; linear position-sensitive detector covering 12° in 2θ 2θ range, 5°-70° step size, 0.017° data collection time, 12 h; foil sample holder].
  • 36
    • 61349124293 scopus 로고    scopus 로고
    • The significant background in the powder X-ray diffraction pattern provides possible evidence for an amorphous component, although we note that the majority of the background in the powder X-ray diffraction pattern can be attributed to scattering from the tape used to hold the sample in the foil sample holder and recalling that the powder X-ray diffraction data were recorded in transmission mode, As the background is subtracted from the powder X-ray diffraction data in the structure determination calculations, the structural analysis discussed here considers only the Bragg scattering due to the crystalline polymer phase
    • The significant background in the powder X-ray diffraction pattern provides possible evidence for an amorphous component, although we note that the majority of the background in the powder X-ray diffraction pattern can be attributed to scattering from the tape used to hold the sample in the foil sample holder (and recalling that the powder X-ray diffraction data were recorded in transmission mode). As the background is subtracted from the powder X-ray diffraction data in the structure determination calculations, the structural analysis discussed here considers only the Bragg scattering due to the crystalline polymer phase.
  • 38
    • 84868911243 scopus 로고    scopus 로고
    • 1H 90° pulse length was 5 μs, and the recycle delay was 150 s.
    • 1H 90° pulse length was 5 μs, and the recycle delay was 150 s.
  • 50
    • 84868903977 scopus 로고    scopus 로고
    • 3.
    • 3.
  • 51
    • 61349130167 scopus 로고    scopus 로고
    • The packing efficiencies are calculated to be 68.9% and 69.9% for the monomer and polymer structures, respectively
    • The packing efficiencies are calculated to be 68.9% and 69.9% for the monomer and polymer structures, respectively.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.