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Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality

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Science Advances  03 Nov 2017:
Vol. 3, no. 11, e1701208
DOI: 10.1126/sciadv.1701208
  • Fig. 1 Chemical structures of the BIC derivatives and 1-octanol analogs.

    To abbreviate a 1-octanol analog, letter “S” or “R” and a number are used to represent the spatial configuration and the position of the chiral center, respectively, and letter O represents octanol. Similarly, to abbreviate a BIC analog, one letter S or R symbolizes an S-type or R-type chiral center at one side chain.

  • Fig. 2 Enantiomorphous honeycomb networks of the BIC-C7/1-octanol coassembly.

    High-resolution STM images of (A) the CW network and (B) the CCW network in the BIC-C7/1-octanol coassembly. I = 0.500 nA and Vbias = 0.900 V. (C) Formation of the enantiomorphous networks in the BIC-C7/1-octanol coassembly. The thick blue sticks, thin blue sticks, and yellow sticks represent the backbones of BIC-C7, side chains of BIC-C7, and 1-octanol molecules, respectively. The blue arrows indicate the chirality of the networks.

  • Fig. 3 Chiral induction triggered by (S)-6O in the 2D assembly of BIC-C7.

    (A) High-resolution STM image of the BIC-C7/(S)-6O coassembly. I = 0.400 nA and Vbias = 0.900 V. (B) Calculated molecular model of the trimeric unit in the BIC-C7/(S)-6O assembly. The red dot marks the (S)-type chiral center in (S)-6O. (C) Chiral coadsorber-induced chirality in the BIC-C7/(S)-6O assembly. The thick blue sticks, thin blue sticks, and red sticks represent the backbones of BIC-C7, side chains of BIC-C7, and coadsorbed (S)-6O molecules, respectively. (D) Plot of the coverage of the CW network in the assembly (RCW, estimated based on the number of domains) versus the fraction of (S)-6O in a mixed solution of (S)-6O and 1-octanol.

  • Fig. 4 Intrinsic molecular chirality induced the 2D molecular assembly.

    (A) High-resolution STM image of the (R)-BIC-C7/1-octanol assembly. I = 0.400 nA and Vbias = 0.900 V. (B) Calculated molecular model of the CCW trimer unit in the (R)-BIC-C7/1-octanol coassembly. The green dot marks the (R)-type chiral center in (R)-BIC-C7. (C) Formation of CCW trimer in the (R)-BIC-C7/1-octanol coassembly. The thick blue sticks, thin blue sticks, and green sticks represent the backbones, achiral side chains, and side chains with a chiral center of (R)-BIC-C7, respectively. The yellow sticks represent the coadsorbed 1-octanol molecules. (D) Plot of the coverage of the CW network in the ((S)-BIC-C7 + BIC-C7)/1-octanol assembly (RCW, estimated based on the number of domains) versus the fraction of (S)-BIC-C7 (compared to the total content of BIC analogs) in the solution.

  • Fig. 5 Chiral competitive coassembly of (R)-BIC-C7 and (S)-6O.

    (A) High-resolution STM image of the CW network in the (R)-BIC-C7/(S)-6O coassembly. I = 0.400 nA and Vbias = 0.900 V. (B) Formation of the CW trimeric unit in the (R)-BIC-C7/(S)-6O coassembly. The thick blue sticks, thin blue sticks, and green sticks represent the backbones, achiral side chains, and side chains with an (R)-type chiral center of (R)-BIC-C7, respectively. The red sticks represent the coadsorbed (S)-6O. (C) Plot of the coverage of the CW honeycomb network in the assembly (RCW, estimated based on the number of domains) versus the fraction of (S)-6O (black line) or (R)-6O (red line) in the solution. (D) Calculated molecular model of the CW trimeric unit in the (R)-BIC-C7/(S)-6O assembly. The green and red dots mark the (R)-type and (S)-type chiral centers, respectively.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/11/e1701208/DC1

    fig. S1. Relationship between the BIC-C7/1-octanol assembly and the substrate lattice.

    fig. S2. Calculated molecular models of the BIC-C7/1-octanol assembly.

    fig. S3. Formation of the CW network in the BIC-C7/(R)-6O assembly.

    fig. S4. Coassembly of (S)-BIC-C7 and 1-octanol.

    fig. S5. Chiral competitive coassembly of (S)-BIC-C7 and (R)-6O.

    fig. S6. Typical STM image of the assembly when (R)-BIC-C7, 1-octanol, and (S)-6O are codeposited together.

    fig. S7. Chiral competition between chiral coabsorber and (R,R)-BIC-C7 [or (S,S)-BIC-C7].

    fig. S8. Coassembly of (R)-BIC-C7 and 1-octanol before and after the presence of (S)-4O.

    fig. S9. Adaptable adsorption conformation of a trimeric unit in the BIC-C7/1-octanol coassembly.

    fig. S10. Calculated hexagonal units of the networks in the BIC-C7/(S)-6O coassembly.

    fig. S11. Calculated hexagonal units of the networks in the (R)-BIC-C7/1-octanol coassembly.

    fig. S12. Calculated hexagonal units of the networks in the (R)-BIC-C7/(S)-6O coassembly.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Relationship between the BIC-C7/1-octanol assembly and the substrate lattice.
    • fig. S2. Calculated molecular models of the BIC-C7/1-octanol assembly.
    • fig. S3. Formation of the CW network in the BIC-C7/(R)-6O assembly.
    • fig. S4. Coassembly of (S)-BIC-C7 and 1-octanol.
    • fig. S5. Chiral competitive coassembly of (S)-BIC-C7 and (R)-6O.
    • fig. S6. Typical STM image of the assembly when (R)-BIC-C7, 1-octanol, and (S)-6O are codeposited together.
    • fig. S7. Chiral competition between chiral coabsorber and (R,R)-BIC-C7 or (S,S)-BIC-C7.
    • fig. S8. Coassembly of (R)-BIC-C7 and 1-octanol before and after the presence of (S)-4O.
    • fig. S9. Adaptable adsorption conformation of a trimeric unit in the BIC-C7/1-octanol coassembly.
    • fig. S10. Calculated hexagonal units of the networks in the BIC-C7/(S)-6O coassembly.
    • fig. S11. Calculated hexagonal units of the networks in the (R)-BIC-C7/1-octanol coassembly.
    • fig. S12. Calculated hexagonal units of the networks in the (R)-BIC-C7/(S)-6O coassembly.

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