Research ArticleORGANIC CHEMISTRY

Near-IR squaraine dye–loaded gated periodic mesoporous organosilica for photo-oxidation of phenol in a continuous-flow device

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Science Advances  11 Sep 2015:
Vol. 1, no. 8, e1500390
DOI: 10.1126/sciadv.1500390
  • Fig. 1 Schematic representation of the preparation and 1O2 generation of Sq-azo@PMO.

    Overall process for the preparation of Sq-azo@PMO and its capability for the photo-oxidation of phenol in water.

  • Fig. 2 Photoisomerization of azo@PMO.

    (A) Schematic representation of reversible isomerization between trans-azo@PMO and cis-azo@PMO under light irradiation and heat. a.u., absorbance units. (B) UV/Vis absorption spectra of Ph-PMO-NH2, cis-azo@PMO, and trans-azo@PMO (1.5 mg ml−1 in aqueous solution). The changes in the UV/Vis absorption spectra due to the isomerization of trans-azo@PMO to cis-azo@PMO (1.5 mg ml−1) were recorded under the irradiation of 383-nm UV light for 20 min. (C) Absorbance changes of the UV/Vis spectra of azo@PMO at 383 nm as a function of cycles upon alternating UV light irradiation and heating at 55°C.

  • Fig. 3 Photophysical studies of Sq-azo@PMO.

    (A) UV/Vis absorption spectra of Sq in dichloromethane (DCM) (red curve), trans-azo@PMO in water (black curve), and Sq-azo@PMO in water (blue curve). (B) Emission spectra of Sq in DCM (red curve) and Sq-azo@PMO in water (blue curve).

  • Fig. 4 TEM images of PMOs.

    (A to D) TEM images of (A) Ph-PMO, (B) Ph-PMO-NH2, (C) trans-azo@PMO, and (D) Sq-azo@PMO.

  • Fig. 5 Microfluidic free-flow device loaded with Sq-azo@PMO for photo-oxidation of phenol.

    (A) Photograph of the microfluidic device under normal light. (B) Operational mode of Sq-azo@PMO loaded microreactor under the irradiation of 664-nm light. Scale bar, 1 cm. (C and D) Photo-oxidation of phenol inside the microfluidic channel as a function of cycles upon (C) alternating irradiation of light and (D) continuous irradiation of light.

  • Table 1 Textural and porosity data of different PMOs.
    No.PMOBET (m2 g−1)Pore diameter (nm)
    1Ph-PMO10786.2
    2Ph-PMO-NH27273.7
    3trans-azo@PMO5442.5
    4Sq-azo@PMO4701.7

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/1/8/e1500390/DC1

    Experimental section

    Fig. S1. Synthetic route for two-step amination of Ph-PMO.

    Fig. S2. Synthetic route for the preparation of azobenzene compounds.

    Fig. S3. Synthetic route for Sq dye.

    Fig. S4. Difference between consecutive absorbance at each time intervals was plotted against time for (a) the absorption decrease of ADMA upon the irradiation of 664 nm light by mixing with aqueous suspension of Sq-azo@PMO under stirring, and (b) the absorption decrease of ADMA upon the irradiation of 660 nm light by mixing with aqueous suspension of MB under stirring.

    Table S1. EA results of various PMO materials.

    FT-IR analyses of PMOs

    Fig. S5. FT-IR spectra of (a) Ph-PMO, Ph-PMO-NO2, and Ph-PMO-NH2 as well as (b) trans-azo@PMO.

    13C CP-MAS NMR analyses of PMOs.

    Fig. S6. 13C CP-MAS solid-state NMR spectra of Ph-PMO, Ph-PMO-NH2, and trans-azo@PMO.

    29Si CP-MAS NMR analyses of PMOs

    Fig. S7. 29Si CP-MAS solid-state NMR spectra of (a) Ph-PMO-NH2 and (b) trans-azo@PMO.

    UV/Vis analyses of Sq-azo@PMO and azo@PMO

    Fig. S8. UV/Vis spectra of (a) Sq-trans-azo@PMO measured after 48 hours of stirring in DCM and (b) azo@PMO obtained after the removal of Sq in DCM.

    TEM images of Sq-azo@PMO and azo@PMO

    Fig. S9. Wall thickness from TEM images of (a) Ph-PMO and (b) azo@PMO obtained after the removal of Sq from Sq-trans-azo@PMO.

    Fig. S10. TEM images of (a and b) Sq-azo@PMO and (c and d) azo@PMO obtained after the removal of Sq from Sq-trans-azo@PMO.

    N2 adsorption/desorption measurements of PMOs

    Fig. S11. Plots for N2 adsorption/desorption isotherms with NLDFT pore size distribution (in the insets) of (a) Ph-PMO, (b) Ph-PMO-NH2, (c) trans-azo@PMO, and (d) Sq-azo@PMO.

    UV/Vis analysis of Sq-trans-azo@PMO and Sq-cis-azo@PMO

    Fig. S12. UV/Vis absorption spectra of (a) Sq-trans-azo@PMO in water and (b) Sq-cis-azo@PMO obtained after irradiation of 383 nm UV light on Sq-trans-azo@PMO in water for 60 min.

    Generation of 1O2 by Sq-azo@PMO in aqueous medium

    Fig. S13. UV/Vis absorption spectra of (a) ADMA in aqueous solution, (b) Sq-azo@PMO in aqueous suspension, and (c) ADMA along with Sq-azo@PMO in aqueous solution.

    Fig. S14. UV/Vis absorption changes of ADMA aqueous solution in the presence of (a) Sq-azo@PMO and (b) trans-azo@PMO upon the irradiation of 664 nm light.

    Photo-oxidation of phenol in aqueous medium

    Fig. S15. Production of BQ as a function of time in cuvette-based aqueous phase.

    Fig. S16. (a) Photograph of microfluidic channels, (b) loading of Sq-azo@PMO in the cavity, and (c) schematic representation of the cross-sectional view of the prepared microreactor.

    UV/Vis analysis of Sq-azo@PMO before and after photo-oxidation reaction

    Fig. S17. UV/Vis absorption spectra of Sq-azo@PMO in water (a) before the photo-oxidation reaction and (b) after recovered from the photo-oxidation reaction in a microfluidic reactor.

    Preparation of Sq@PhPMO for control study

    Fig. S18. UV/Vis absorption spectrum of Sq@PhPMO in water.

    References (4446)

  • Supplementary Materials

    This PDF file includes:

    • Experimental section
    • Fig. S1. Synthetic route for two-step amination of Ph-PMO.
    • Fig. S2. Synthetic route for the preparation of azobenzene compounds.
    • Fig. S3. Synthetic route for Sq dye.
    • Fig. S4. Difference between consecutive absorbance at each time intervals was plotted against time for (a) the absorption decrease of ADMA upon the irradiation of 664 nm light by mixing with aqueous suspension of Sq-azo@PMO under stirring, and (b) the absorption decrease of ADMA upon the irradiation of 660 nm light by mixing with aqueous suspension of MB under stirring.
    • Table S1. EA results of various PMO materials.
    • FT-IR analyses of PMOs
    • Fig. S5. FT-IR spectra of (a) Ph-PMO, Ph- PMO-NO2, and Ph-PMO-NH2 as well as (b) trans-azo@PMO.
      13C CP-MAS NMR analyses of PMOs
    • Fig. S6. 13C CP-MAS solid-state NMR spectra of Ph-PMO, Ph-PMO-NH2, and trans-azo@PMO.
    • 29Si CP-MAS NMR analyses of PMOs
      Fig. S7. 29Si CP-MAS solid-state NMR spectra of (a) Ph-PMO-NH2 and (b) trans-azo@PMO.
      UV/Vis analyses of Sq-azo@PMO and azo@PMO
    • Fig. S8. UV/Vis spectra of (a) Sq-trans-azo@PMO measured after 48 hours of stirring in DCM and (b) azo@PMO obtained after the removal of Sq in DCM.
    • TEM images of Sq-azo@PMO and azo@PMO
    • Fig. S9. Wall thickness from TEM images of (a) Ph-PMO and (b) azo@PMO obtained after the removal of Sq from Sq-trans-azo@PMO.
    • Fig. S10. TEM images of (a and b) Sq-azo@PMO and (c and d) azo@PMO obtained after the removal of Sq from Sq-trans-azo@PMO.
    • N2 adsorption/desorption measurements of PMOs
    • Fig. S11. Plots for N2 adsorption/desorption isotherms with NLDFT pore size distribution (in the insets) of (a) Ph-PMO, (b) Ph-PMO-NH2, (c) trans-azo@PMO, and (d) Sq-azo@PMO.
    • UV/Vis analysis of Sq-trans-azo@PMO and Sq-cis-azo@PMO
    • Fig. S12. UV/Vis absorption spectra of (a) Sq-trans-azo@PMO in water and (b) Sq-cis-azo@PMO obtained after irradiation of 383 nm UV light on Sq-trans-azo@PMO in water for 60 min.
    • Generation of 1O2 by Sq-azo@PMO in aqueous medium
    • Fig. S13. UV/Vis absorption spectra of (a) ADMA in aqueous solution, (b) Sq-azo@PMO in aqueous suspension, and (c) ADMA along with Sq-azo@PMO in aqueous solution.
    • Fig. S14. UV/Vis absorption changes of ADMA aqueous solution in the presence of (a) Sqazo@PMO and (b) trans-azo@PMO upon the irradiation of 664 nm light.
    • Photo-oxidation of phenol in aqueous medium
    • Fig. S15. Production of BQ as a function of time in cuvette-based aqueous phase.
    • Fig. S16. (a) Photograph of microfluidic channels, (b) loading of Sq-azo@PMO in the cavity, and (c) schematic representation of the cross-sectional view of the prepared microreactor.
    • UV/Vis analysis of Sq-azo@PMO before and after photo-oxidation reaction
    • Fig. S17. UV/Vis absorption spectra of Sq-azo@PMO in water (a) before the photo-oxidation reaction and (b) after recovered from the photo-oxidation reaction in a microfluidic reactor.
    • Preparation of Sq@PhPMO for control study
    • Fig. S18. UV/Vis absorption spectrum of Sq@PhPMO in water.
    • References (44–46)

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