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Volumn 48, Issue 47, 2009, Pages 8874-8877

Reusable catalysts based on dendrimers trapped in poly(p-xylylene) nanotubes

Author keywords

Dendrlmers; Electrospmning; Organocatalysis; Oxidation; Polymers

Indexed keywords

CATALYTIC ACTIVITY; CO-ELECTROSPINNING; DENDRLMERS; ELECTROSPMNING; ORGANOCATALYSIS; ORGANOCATALYSTS; PAMAM DENDRIMER; REUSABLE CATALYSTS;

EID: 70449119328     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200903448     Document Type: Article
Times cited : (27)

References (58)
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    • For the immobilization of catalysts, see: a
    • For the immobilization of catalysts, see: a) J. M. Fraile, J.I. Garcia, J. A. Mayoral, Chem. Rev. 2009, 109, 360;
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    • Fraile, J.M.1    Garcia, J.I.2    Mayoral, J.A.3
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    • For the immobilization of TEMPO, see
    • For the immobilization of TEMPO, see: C Bolm, T. Fey, Chem. Commun. 1999, 1795;
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    • Bolm, C.1    Fey, T.2
  • 43
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    • (2004) Adv. Mater. , vol.16 , pp. 1151
    • Li, D.1    Xia, Y.2
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    • We performed solid-state NMR studies to investigate the material obtained after water extraction. We found that around 15-20% of the initial added PEO remained in the tube material (representative NMR spectra are shown in the Supporting Information). The PEO used has a broad molecular weight distribution and we believe that the longest chains were not extracted. We would like to point out that it is wellestablished in terms of theory and experiments that, other than the diffusion of three-dimensional particles such as dendrimers, the diffusion of flexible polymer chains through polymer matrices is not controlled by their hydrodynamic radius but follows reptational motions (i.e., along the length of the chain) so that even rather long chain molecules are able to pass through polymer membranes, see: K. Kremer, G. S. Grest
    • We performed solid-state NMR studies to investigate the material obtained after water extraction. We found that around 15-20% of the initial added PEO remained in the tube material (representative NMR spectra are shown in the Supporting Information). The PEO used has a broad molecular weight distribution and we believe that the longest chains were not extracted. We would like to point out that it is wellestablished in terms of theory and experiments that, other than the diffusion of three-dimensional particles such as dendrimers, the diffusion of flexible polymer chains through polymer matrices is not controlled by their hydrodynamic radius but follows reptational motions (i.e., along the length of the chain) so that even rather long chain molecules are able to pass through polymer membranes, see: K. Kremer, G. S. Grest, J. Chem. Phys. 1990, 92, 5057.
    • (1990) J. Chem. Phys. , vol.92 , pp. 5057
  • 51
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    • Leaching studies with water were performed on core-shell fibers prior to removal of the PEO fibers, in order to make sure that leaching that occurs during core fiber extraction will, also be taken into account.
    • Leaching studies with water were performed on core-shell fibers prior to removal of the PEO fibers, in order to make sure that leaching that occurs during core fiber extraction will, also be taken into account.
  • 54
    • 70449135520 scopus 로고    scopus 로고
    • We also conjugated the dendrimers inside the tubes by adding isothiocyanates containing fluorescein (see the Supporting Information). Gravimetry showed that around 57% of the amino groups were dye-functionalized. These mats showed the typical color. However, for the G4 system after extraction, gravimetry showed that dye functionalization was not successful, thus further indicating that only very small amounts of 04 are present in the system. Unfortunately, confocal fluorescence microscopy did not allow us to learn about the distribution of the dye-loaded catalysts within the tube system.
    • We also conjugated the dendrimers inside the tubes by adding isothiocyanates containing fluorescein (see the Supporting Information). Gravimetry showed that around 57% of the amino groups were dye-functionalized. These mats showed the typical color. However, for the G4 system after extraction, gravimetry showed that dye functionalization was not successful, thus further indicating that only very small amounts of 04 are present in the system. Unfortunately, confocal fluorescence microscopy did not allow us to learn about the distribution of the dye-loaded catalysts within the tube system.
  • 56
    • 70449125565 scopus 로고    scopus 로고
    • We found that the background reaction was slow (7 % ) under the applied conditions. The "background yield" was also obtained by using the G4 system after water extraction, thus further supporting that only very small amounts of G4 dendrimers remained in the tubes after extraction.
    • We found that the background reaction was slow (7 % ) under the applied conditions. The "background yield" was also obtained by using the G4 system after water extraction, thus further supporting that only very small amounts of G4 dendrimers remained in the tubes after extraction.
  • 58
    • 70449125564 scopus 로고    scopus 로고
    • The morphology of the tube material altered over time as partial decomposition of the PPX tube material probably occurred under the strongly oxidizing conditions. This explanation is supported by the observation that morphology change was not observed for system. A while studying the Knoevenagel condensation.
    • The morphology of the tube material altered over time as partial decomposition of the PPX tube material probably occurred under the strongly oxidizing conditions. This explanation is supported by the observation that morphology change was not observed for system. A while studying the Knoevenagel condensation.


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