Research ArticleSOLID STATE PHYSICS

Tunable chiral metal organic frameworks toward visible light–driven asymmetric catalysis

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Science Advances  18 Aug 2017:
Vol. 3, no. 8, e1701162
DOI: 10.1126/sciadv.1701162
  • Scheme 1 Basic illustration, ligand design, and synthesis.

    (A) Scheme of photocatalytic asymmetric α-alkylation of aldehyde by MOFs that are constructed with chiral photoredox ligands and metal ions. (B) Route to synthesize chiral photoredox ligands.

  • Fig. 1 XRD patterns of crystalline MOFs.

    (A to F) Zn-MOF (A), Zr-MOF (C), and Ti-MOF (E) before (black curves) and after (red curves) Boc group removal. Corresponding crystal structures of Zn-MOF (B), Zr-MOF (D), and Ti-MOF (F). In the crystal structures, metal ion is included in the polyhedron, oxygen atom is in red color, carbon atom is in brown color, and the ball in blue color represents a functional group with chiral induction and catalytic ability.

  • Fig. 2 The light property measurements.

    (A) UV-vis absorption spectra of H2BDC-NH2 and chiral HL and (B) UV-vis absorption spectra of Zn-MOF, Zr-MOF, and Ti-MOF. CD spectra of (C) chiral HL, (D) Zn MOF, (E) Zr-MOF, and (F) Ti-MOF.

  • Table 1 Catalytic performance under different conditions.

    THF, tetrahydrofuran.

    EntryOutput
    (W)
    CatalystTemperature
    (°C)
    SolventConversion
    (%)
    ee
    (%)
    Substrate: 3-phenylpropionaldehyde*
    1200S-HL0DMF50+78
    2200R-HL20DMF52−72
    3200S-HL20DMF55+74
    425S-HL20DMF8nd
    525S-Zn-MOF20DMF40+55
    625R-Zn-MOF20DMF38−53
    725S-Zr-MOF20DMF46+64
    825R-Zr-MOF20DMF47−66
    925S-Ti-MOF20DMF95+84
    1025R-Ti-MOF20DMF98−85
    1125S-Ti-MOF0DMF90+87
    1225S-Ti-MOF20THF21+45
    1325S-Ti-MOF20CH3CN43+56
    14S-Ti-MOF20DMF5nd
    152520DMF0nd
    Substrate: cis-6-nonenal*
    1625S-Ti-MOF20DMF97+85
    1725R-Ti-MOF20DMF98−84

    *Catalytic condition: catalyst (0.025 mmol, 0.05 equiv), alkyl bromide (0.5 mmol, 1 equiv), aldehyde (1.0 mmol, 2 equiv), 2,6-lutidine (1.0 mmol, 2 equiv), and solvent (1 ml) under light irradiation for 20 hours. Light source was 8 cm away from the reaction vessel.

    †Light source used in all reaction was an output tunable xenon lamp housed with a filter to cut off the light at <400 nm.

    ‡nd, not detected; ee value was tested following the reported method.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/8/e1701162/DC1

      Supplementary Text

      scheme S1. Pathway to synthesize chiral Boc-HL.

      scheme S2. Pathway to synthesize chiral HL.

      scheme S3. Proposed reaction mechanism for visible light–driven asymmetric α-alkylation of aldehydes in the presence of chiral MOFs.

      fig. S1. 1H NMR spectrum of 2-aminoterephthalic acid.

      fig. S2. 1H NMR spectrum of N-(tert-butoxycarbonyl)-prolinal.

      fig. S3. 1H NMR spectrum of Boc-HL without hydrogenation.

      fig. S4. 1H NMR spectrum of Boc-HL.

      fig. S5. 13C NMR spectrum of Boc-HL.

      fig. S6. 1H NMR spectrum of HL.

      fig. S7. Absorption spectra (200 to 500 nm) of chiral N-Boc-prolinal, H2BDC-NH2, and chiral HL.

      fig. S8. FT-IR spectra of chiral Boc-HL, Boc-Zn-MOF, Boc-Zr-MOF, and Boc-Ti-MOF.

      fig. S9. TGA of Boc-metal-MOFs.

      fig. S10. SEM images of Zn-MOF, Zr-MOF, and Ti-MOF.

      fig. S11. N2 adsorption-desorption isotherms of Boc-Zn-MOF and Zn-MOF.

      fig. S12. N2 adsorption-desorption isotherms of Boc-Zr-MOF and Zr-MOF.

      fig. S13. N2 adsorption-desorption isotherms of Boc-Ti-MOF and Ti-MOF.

      fig. S14. FT-IR spectra of Boc-Ti-MOF and Ti-MOF.

      fig. S15. Photos of catalysts, Zn-MOF, Zr-MOF, and Ti-MOF.

      fig. S16. Photos illustrating the experimental process of photocatalysis.

      fig. S17. GC-MS result for standard reaction in absence of light illumination.

      fig. S18. GC-MS result for catalytic reaction with pure chiral HL at 20°C and under 25-W illumination.

      fig. S19. GC-MS result for catalytic reaction with chiral Zn-MOF at 20°C and under 25-W illumination.

      fig. S20. GC-MS result for catalytic reaction with chiral Zr-MOF at 20°C and under 25-W illumination.

      fig. S21. GC-MS result for catalytic reaction with chiral Ti-MOF at 20°C and under 25-W illumination.

      fig. S22. MS spectrum of 3-phenylpropionaldehyde.

      fig. S23. MS spectrum of cis-6-nonenal.

      fig. S24. MS spectrum of diethyl bromomalonate.

      fig. S25. MS spectrum of product 1.

      fig. S26. MS spectrum of product 2.

      fig. S27. Reaction time–dependent conversion using Ti-MOFs as catalyst at 20°C.

      fig. S28. Representative 1H NMR spectrum for determining ee value of the product obtained with racemic Ti-MOF (3-phenylpropionaldehyde as substrate).

      fig. S29. Representative 1H NMR spectrum for determining ee value of the product obtained with S-Ti-MOF (3-phenylpropionaldehyde as substrate).

      fig. S30. Representative 1H NMR spectrum for determining ee value of the product obtained with R-Ti-MOF (3-phenylpropionaldehyde as substrate).

      fig. S31. XRD patterns of chiral Ti-MOF after recycle use for three times.

      fig. S32. FT-IR spectra of 3-phenylpropionaldehyde, Ti-MOF, and their mixture.

      fig. S33. X-ray photoelectron spectroscopy spectra of Ti-MOF and mixture of Ti-MOF and diethyl bromomalonate.

      fig. S34. FT-IR spectra of bromomalonate, Ti-MOF, and their mixture.

      fig. S35. Diagram of energy level for alkyl bromide and Ti-MOF (versus saturated calomel electrode).

      table S1. Catalytic performance with error ranges.

      table S2. Contrast tests by using Boc-protected chiral ligand, corresponding MOFs, or large output of light source.

      table S3. Catalytic property of reused MOFs.

      References (6066)

    • Supplementary Materials

      This PDF file includes:

      • Supplementary Text
      • scheme S1. Pathway to synthesize chiral Boc-HL.
      • scheme S2. Pathway to synthesize chiral HL.
      • scheme S3. Proposed reaction mechanism for visible light–driven asymmetric α-alkylation of aldehydes in the presence of chiral MOFs.
      • fig. S1. 1H NMR spectrum of 2-aminoterephthalic acid.
      • fig. S2. 1H NMR spectrum of N-(tert-butoxycarbonyl)-prolinal.
      • fig. S3. 1H NMR spectrum of Boc-HL without hydrogenation.
      • fig. S4. 1H NMR spectrum of Boc-HL.
      • fig. S5. 13C NMR spectrum of Boc-HL.
      • fig. S6. 1H NMR spectrum of HL.
      • fig. S7. Absorption spectra (200 to 500 nm) of chiral N-Boc-prolinal, H2BDC-NH2, and chiral HL.
      • fig. S8. FT-IR spectra of chiral Boc-HL, Boc-Zn-MOF, Boc-Zr-MOF, and Boc-Ti-MOF.
      • fig. S9. TGA of Boc-metal-MOFs.
      • fig. S10. SEM images of Zn-MOF, Zr-MOF, and Ti-MOF.
      • fig. S11. N2 adsorption-desorption isotherms of Boc-Zn-MOF and Zn-MOF.
      • fig. S12. N2 adsorption-desorption isotherms of Boc-Zr-MOF and Zr-MOF.
      • fig. S13. N2 adsorption-desorption isotherms of Boc-Ti-MOF and Ti-MOF.
      • fig. S14. FT-IR spectra of Boc-Ti-MOF and Ti-MOF.
      • fig. S15. Photos of catalysts, Zn-MOF, Zr-MOF, and Ti-MOF.
      • fig. S16. Photos illustrating the experimental process of photocatalysis.
      • fig. S17. GC-MS result for standard reaction in absence of light illumination.
      • fig. S18. GC-MS result for catalytic reaction with pure chiral HL at 20°C and under 25-W illumination.
      • fig. S19. GC-MS result for catalytic reaction with chiral Zn-MOF at 20°C and under 25-W illumination.
      • fig. S20. GC-MS result for catalytic reaction with chiral Zr-MOF at 20°C and under 25-W illumination.
      • fig. S21. GC-MS result for catalytic reaction with chiral Ti-MOF at 20°C and under 25-W illumination.
      • fig. S22. MS spectrum of 3-phenylpropionaldehyde.
      • fig. S23. MS spectrum of cis-6-nonenal.
      • fig. S24. MS spectrum of diethyl bromomalonate.
      • fig. S25. MS spectrum of product 1.
      • fig. S26. MS spectrum of product 2.
      • fig. S27. Reaction time–dependent conversion using Ti-MOFs as catalyst at 20°C.
      • fig. S28. Representative 1H NMR spectrum for determining ee value of the product obtained with racemic Ti-MOF (3-phenylpropionaldehyde as substrate).
      • fig. S29. Representative 1H NMR spectrum for determining ee value of the product obtained with S-Ti-MOF (3-phenylpropionaldehyde as substrate).
      • fig. S30. Representative 1H NMR spectrum for determining ee value of the product obtained with R-Ti-MOF (3-phenylpropionaldehyde as substrate).
      • fig. S31. XRD patterns of chiral Ti-MOF after recycle use for three times.
      • fig. S32. FT-IR spectra of 3-phenylpropionaldehyde, Ti-MOF, and their mixture.
      • fig. S33. X-ray photoelectron spectroscopy spectra of Ti-MOF and mixture of
        Ti-MOF and diethyl bromomalonate.
      • fig. S34. FT-IR spectra of bromomalonate, Ti-MOF, and their mixture.
      • fig. S35. Diagram of energy level for alkyl bromide and Ti-MOF (versus saturated calomel electrode).
      • table S1. Catalytic performance with error ranges.
      • table S2. Contrast tests by using Boc-protected chiral ligand, corresponding MOFs, or large output of light source.
      • table S3. Catalytic property of reused MOFs.
      • References (60–66)

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