Research ArticleMATERIALS SCIENCE

Rational synthesis of an atomically precise carboncone under mild conditions

See allHide authors and affiliations

Science Advances  23 Aug 2019:
Vol. 5, no. 8, eaaw0982
DOI: 10.1126/sciadv.aaw0982
  • Fig. 1 Structures of carboncone.

    (A) Illustration of all five types of carboncone[n,m] (n = 1 to 5, m = 3 and 4). The bonds of pentagon are marked with green lines. The circles of fused rings are painted with orange, pink, yellow, and white from tips to rims, respectively. The black dot points to the cone tip. (B) The Oak Ridge thermal-ellipsoid plot (ORTEP) diagram of the penta-mesityl carboncone[1,2] derivative (1b) at 50% probability with hydrogen atoms and solvent molecules omitted for clarity (top view), and stick model diagram of crystallographic structure of 1b with five mesityl groups, hydrogen atoms, and solvent molecules omitted for clarity (side view). The cone height and the apex angle in the crystal are displayed.

  • Fig. 2 Three-step organic synthesis of the carboncone[1,2] derivatives 1 from corannulene 2.

    Conditions: (i.) (Ir(OMe)cod)2 [20 mole percent (mol %)], B2(pin)2 (6.5 equiv.), 4,4′-dimetylpyridine (40 mol %), sodium methoxide (10 mol %), cyclohexane, 85°C, 4 days; (ii.) 1-bromonaphthalene or 1-bromo-4-mesitylnaphthalene (10 equiv.), Pd(PPh3)4 (25 mol %), Cs2CO3 (30 equiv.), toluene/H2O (2:1), 100°C, 24 hours; (iii.) DDQ (20 equiv.), TfOH/CH2Cl2 (1:20), 10 min. cod, 1,5-cyclooctadiene; pin, pinacolato; cat., catalyst; DDQ, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

  • Fig. 3 A rational ring closure pathway from the precursor 5a toward 1a calculated by a dication pathway.

    Here, ∆E represents the energy barrier for each step of cyclization. The NICS values of the rings in all intermediate products from A1 to A11 are presented.

  • Fig. 4 Spectrometric and electrochemical properties of the penta-mesityl carboncone[1,2] derivative (1b).

    (A) Ultraviolet-visible (UV-vis) absorption (black solid line), the oscillator strengths (blue bars) obtained by TD-DFT calculations at the B3LYP/6-31G(d,p) level of theory, and emission spectra (red dashed line) of 1b in CH2Cl2. Inset: Digital photograph of a CH2Cl2 solution of 1b irradiated at 456 nm. (B) IR absorption spectrum of 1b. Asterisks mark the dominant bands and humps at 1120.5, 1384.7, 1637.3, 2850.4, and 2919.8 cm−1 in the observed spectrum (red). A theoretical spectrum (black) calculated at the B3LYP/6-31G(d,p) level of theory is shown for comparison. (C) Cyclic voltammogram of 1b and corannulene in N,N-dimethylformamide. (D) The first redox process of 1b measured in o-dichlorobenzene at variable scan rates (120, 100, 80, 60, 40, 20, and 10 mV/s).

  • Fig. 5 Topology structure and strategy for the bottom-up synthesis of structurally uniform carboncones[1,m].

    Carboncone[1,2] molecule (1) is formed by introducing a 60° positive disclination defect in the nanographene sheet, and the growth of carboncone[1,m > 2] undergoes epitaxial expansion from the carboncone[1,2] seed molecule (1).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/8/eaaw0982/DC1

    Fig. S1. Full synthetic scheme of 1.

    Fig. S2. NMR spectra of S2.

    Fig. S3. NMR spectra of 4b.

    Fig. S4. 1H NMR (400 MHz) spectra of 5a.

    Fig. S5. 1H NMR spectra of 5b.

    Fig. S6. 13C NMR spectra of 5b.

    Fig. S7. MALDI-TOF mass spectra of C70H20 (1a).

    Fig. S8. MALDI-TOF mass spectra of C115H70 (1b).

    Fig. S9. 1H NMR spectrum of the carboncone (1b).

    Fig. S10. Theoretical simulations for 1H NMR spectra of 1b and the possible heptagon-containing isomer.

    Fig. S11. 13C NMR spectrum of the carboncone (1b).

    Fig. S12. Packing mode of 1b in the crystal.

    Fig. S13. The transition state (TS) structures for cone-to-cone inversion of 1a and 1b.

    Fig. S14. IRC calculation results of the inversion TS of 1a and 1b.

    Fig. S15. Structures of compounds 7, 8, 9b, and 10b.

    Fig. S16. Energy barriers for different ring closure steps on A2 and the relative energies of the intermediate products by a dication pathway.

    Fig. S17. Energy barriers for different ring closure steps on A3 and the relative energies of the intermediate products by a dication pathway.

    Fig. S18. Energy barriers for different ring closure steps on A4 and the relative energies of the intermediate products by a dication pathway.

    Fig. S19. Energy barriers for different ring closure steps on A5 and the relative energies of the intermediate products by a dication pathway.

    Fig. S20. Energy barriers for different ring closure steps on A6 and the relative energies of the intermediate products by a dication pathway.

    Fig. S21. Energy barriers for different ring closure steps on A7 and the relative energies of the intermediate products by a dication pathway.

    Fig. S22. Energy barriers for different ring closure steps on A8 and the relative energies of the intermediate products by a dication pathway.

    Fig. S23. Energy barriers for different ring closure steps on A3′ and the relative energies of the intermediate products by a dication pathway.

    Fig. S24. UV-vis absorption spectra of 7 and 8.

    Fig. S25. Molecular orbitals (from HOMO−1 to LUMO+1) of carboncone 1a and 1b calculated at the B3LYP/6-31G(d,p) level.

    Fig. S26. Molecular orbitals (from HOMO−1 to LUMO+1) of nanographene 7 calculated at the B3LYP/6-31G(d,p) level.

    Fig. S27. Molecular orbitals (from HOMO−1 to LUMO+1) of 2 and 8 calculated at the B3LYP/6-31G(d,p) level.

    Table S1. Crystallographic data and structure refinement details of 1b.

    Table S2. Cartesian coordinates of optimized species at the B3LYP/6-31G(d,p) level on Gaussian 09.

    Table S3. UV-vis absorption of 1a predicted by TD-DFT calculations at the B3LYP/6-31G(d,p) level.

    Table S4. Calculated vibrational frequencies at the B3LYP/6-31G(d,p) level for prominent bands of carboncone 1b in the IR spectrum (in cm−1).

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Full synthetic scheme of 1.
    • Fig. S2. NMR spectra of S2.
    • Fig. S3. NMR spectra of 4b.
    • Fig. S4. 1H NMR (400 MHz) spectra of 5a.
    • Fig. S5. 1H NMR spectra of 5b.
    • Fig. S6. 13C NMR spectra of 5b.
    • Fig. S7. MALDI-TOF mass spectra of C70H20 (1a).
    • Fig. S8. MALDI-TOF mass spectra of C115H70 (1b).
    • Fig. S9. 1H NMR spectrum of the carboncone (1b).
    • Fig. S10. Theoretical simulations for 1H NMR spectra of 1b and the possible heptagon-containing isomer.
    • Fig. S11. 13C NMR spectrum of the carboncone (1b).
    • Fig. S12. Packing mode of 1b in the crystal.
    • Fig. S13. The transition state (TS) structures for cone-to-cone inversion of 1a and 1b.
    • Fig. S14. IRC calculation results of the inversion TS of 1a and 1b.
    • Fig. S15. Structures of compounds 7, 8, 9b, and 10b.
    • Fig. S16. Energy barriers for different ring closure steps on A2 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S17. Energy barriers for different ring closure steps on A3 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S18. Energy barriers for different ring closure steps on A4 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S19. Energy barriers for different ring closure steps on A5 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S20. Energy barriers for different ring closure steps on A6 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S21. Energy barriers for different ring closure steps on A7 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S22. Energy barriers for different ring closure steps on A8 and the relative energies of the intermediate products by a dication pathway.
    • Fig. S23. Energy barriers for different ring closure steps on A3′ and the relative energies of the intermediate products by a dication pathway.
    • Fig. S24. UV-vis absorption spectra of 7 and 8.
    • Fig. S25. Molecular orbitals (from HOMO−1 to LUMO+1) of carboncone 1a and 1b calculated at the B3LYP/6-31G(d,p) level.
    • Fig. S26. Molecular orbitals (from HOMO−1 to LUMO+1) of nanographene 7 calculated at the B3LYP/6-31G(d,p) level.
    • Fig. S27. Molecular orbitals (from HOMO−1 to LUMO+1) of 2 and 8 calculated at the B3LYP/6-31G(d,p) level.
    • Table S1. Crystallographic data and structure refinement details of 1b.
    • Table S2. Cartesian coordinates of optimized species at the B3LYP/6-31G(d,p) level on Gaussian 09.
    • Table S3. UV-vis absorption of 1a predicted by TD-DFT calculations at the B3LYP/6-31G(d,p) level.
    • Table S4. Calculated vibrational frequencies at the B3LYP/6-31G(d,p) level for prominent bands of carboncone 1b in the IR spectrum (in cm−1).

    Download PDF

    Files in this Data Supplement:

Navigate This Article