Selective assemblies of giant tetrahedra via precisely controlled positional interactions

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Science  24 Apr 2015:
Vol. 348, Issue 6233, pp. 424-428
DOI: 10.1126/science.aaa2421
  • Fig. 1 Schematic illustration of the A15 phase.

    (A) In an A15 cubic unit cell, the dark red and pale red colors represent different coordination environments. (B) Schemes of CN = 12 and CN = 14 coordination environments in the A15 lattice. (C) 2D-projected view of the A15 lattice along the 〈001〉 direction. The inset shows a 2D 44 tiling pattern along the z axis. The spheres at the sparse layers (z/4 and 3z/4) are represented by gray circles; the spheres at the dense layers are shown by black and white circles (z/2 and z).

  • Fig. 2 Chemical structures and molecular models (shown in shadow) of the four categories of giant tetrahedra.

    Cartoons in the boxes are corresponding simplifications of the giant tetrahedra, in which blue spheres represent hydrophilic POSS cages and red spheres represent hydrophobic BPOSS cages.

  • Fig. 3 Selectively assembled structures of 2a.

    (A) Combined SAXS and WAXD profiles of 2a evaporated from tetrahydrofuran-acetonitrile (THF/MeCN) mixed solvents at 25°C. (B) BF TEM image and corresponding FFT pattern (inset) of a microtomed thin-sectioned 2a sample. (C) SAXS pattern of 2a after the sample was heated to above its Tm and annealed at 140°C for 12 hours. (D) A {100} plane of an A15 supramolecular lattice was identified by the BF TEM image after the thin-sectioned sample was stained by RuO4. The inset is the FFT pattern of this image. (E) Fourier filtering of the image shown in (D) revealed a clear view of the 2D 44 tiling along the 〈100〉 direction. (F) Inverse colored and magnified image of (E). White spheres represent the hydrophilic POSS domains with different sizes. The inset shows a simulated projection view along the 〈100〉 direction. Spheres in the red-dot circles correspond to the dark red ones shown in Fig. 1A. (G) Schematic illustrations of the selective assembly mechanism and molecular packing in the A15 lattice.

  • Fig. 4 Selectively assembled structures from giant tetrahedra 3 and 4.

    (A to C) SAXS patterns of 3c (A), 3a (B), and 4b (C) were taken at 25°C after corresponding thermal treatments. (D) BF TEM image of thin-sectioned 3c confirms the lamellar lattice deduced from the SAXS result shown in (A). (E) BF TEM image of thin-sectioned and RuO4-stained 3a confirms the double-gyroid lattice deduced from the SAXS result shown in (B). (F) BF TEM image of thin-sectioned 4b confirms the honeycomb-like hexagonal lattice deduced from the SAXS result shown in (C). In (D) to (F), the insets are the FFT patterns of the TEM images. (G) Schematic illustration of the selective assembly mechanisms and packing models of 3a to 3c. (H) Schematic packing models of 4a to 4c.

  • Table 1 Supramolecular lattice analysis of the giant tetrahedra with different symmetry.

    Lattice I structures were formed by slow evaporation of the sample solutions in THF/MeCN mixed solvents at 25°C; lattice II structures were formed after annealing treatment. dI is the determined periodicity of the lamellar structures.

    MoleculeLattice ITm (°C)dI (nm)Lattice IIdII (nm)Μ
    1Triclinic crystal138Disordered
    3aLamellae1775.40Double gyroid6.35

    *Dimensions of the A15 or bcc unit cells.

    †Lamellar periodicities in supramolecular lattice II.

    ‡The corresponding principal (01) spacing between the cylinders in the honeycomb-like hexagonal lattices.

    §Calculated numbers of giant tetrahedra in two types of spheres in the A15 lattice (the size ratios of two types of spheres in 2b and 2c are assumed to be 1.1, the same as in 2a) or in each sphere in the bcc lattice.

    #Average number of giant tetrahedra within 1-nm-thick cross section of the cylinders in the honeycomb-like hexagonal supramolecular lattices.

    Supplementary Materials

    • Selective assemblies of giant tetrahedra via precisely controlled positional interactions

      Mingjun Huang, Chih-Hao Hsu, Jing Wang, Shan Mei, Xuehui Dong, Yiwen Li, Mingxuan Li, Hao Liu, Wei Zhang, Takuzo Aida, Wen-Bin Zhang, Kan Yue, Stephen Z. D. Cheng

      Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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      • Materials and Methods
      • Supplementary Text
      • Figs. S1 to S8
      • Table S1
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