Research ArticleMATERIALS SCIENCE

Gold tetrahedra coil up: Kekulé-like and double helical superstructures

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Science Advances  09 Oct 2015:
Vol. 1, no. 9, e1500425
DOI: 10.1126/sciadv.1500425
  • Fig. 1 Total structure of the Au40(o-MBT)24 cluster.

    (A) Unit cell comprising two enantiomers. (B) Mirror symmetry of the enantiomers. (C) Snowflake-like Au25 kernel with tetrahedral units coiled up into a Kekulé-like superstructure. (D) Six monomeric staples protecting the Kekulé ring. (E) Three trimeric staples protecting the central Au7 bi-tetrahedron. (F) Overall Au40S24 framework. Blue/green, Au atoms in the kernel; orange, Au atoms in the staples; yellow, sulfur; gray, carbon; pink, hydrogen.

  • Fig. 2 Total structure of the Au52(TBBT)32 cluster.

    (A) Unit cell comprising two enantiomers. (B) Mirror symmetry of the enantiomers. (C) Two helical pentatetrahedral strands forming the double helical kernel. (D) Four monomeric staples protecting the waist of the kernel. (E) Four dimeric staples protecting the top and another four protecting the bottom of the kernel. (F) Overall Au52S32 framework. Blue/green, Au atoms in the kernel; orange, Au atoms in the staples; yellow, sulfur; gray, carbon; pink, hydrogen.

  • Fig. 3 Au-Au bond length distributions in the clusters.

    (A) Au40(o-MBT)24. (B) Au52(TBBT)32. Green/blue/magenta/orange, gold; yellow, sulfur.

  • Fig. 4 Anisotropic growth of the gold FCC lattice into a hexagonal prism in Au40(o-MBT)24 and a tetragonal rod in Au52(TBBT)32.

    (A to C) Model of a 43–gold atom hexagonal prism composed of three layers (green, orange, and blue) stacked along the [111] direction in an a-b-c manner (the three arrows indicate the three missing gold atoms in the real Au40 cluster). (D) Au40(o-MBT)24 as a hexagonal prism. (E to G) Model of a 48–gold atom tetragonal rod composed of six layers stacked along the [100] direction. (H) Au52(TBBT)32 as a tetragonal rod. The four gold atoms not included in the FCC lattice are indicated by arrows.

  • Fig. 5 Thiolate bonding and patterning on the crystalline facets of Au40 and Au52.

    (A) Tetragonal configuration of sulfur atom of o-MBT in the Au40 cluster. (B) Tetragonal configuration of sulfur atom of TBBT in Au52. (C) Twelve–gold atom {111} facets on the Au40 cluster. (D) Twelve–gold atom {100} facets on the Au52 cluster. Orange/magenta, Au; yellow, S; gray, C.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/1/9/e1500425/DC1

    Materials and Methods

    Fig. S1. The left- and right-handed isomers of the chiral double helical Au32 kernel in Au52(TBBT)32.

    Fig. S2. DFT-simulated HOMO distribution of Au40(o-MBT)24.

    Fig. S3. DFT-simulated HOMO distribution of Au52(TBBT)32.

    Fig. S4. Arrangement of thiolates on the flat surface of Au40(o-MBT)24 and Au52(TBBT)32 clusters.

    Fig. S5. Penetration of surface bridging forces into the kernel, leading to the segregation of tetrahedral units.

    Table S1. Crystal data and structure refinement for Au40(o-MBT)24.

    Table S2. Crystal data and structure refinement for Au52(TBBT)32.

    Table S3. Atomic coordinates (×104) and equivalent isotropic displacement parameters (Å2 ×103) for Au40(o-MBT)24.

    Table S4. Atomic coordinates (×104) and equivalent isotropic displacement parameters (Å2 × 103) for Au52(TBBT)32.

    Table S5. Calculated atomic charges.

  • Supplementary Materials

    This PDF file includes:

    • Materials and Methods
    • Fig. S1. The left- and right-handed isomers of the chiral double helical Au32 kernel in Au52(TBBT)32.
    • Fig. S2. DFT-simulated HOMO distribution of Au40(o-MBT)24.
    • Fig. S3. DFT-simulated HOMO distribution of Au52(TBBT)32.
    • Fig. S4. Arrangement of thiolates on the flat surface of Au40(o-MBT)24 and Au52(TBBT)32 clusters.
    • Fig. S5. Penetration of surface bridging forces into the kernel, leading to the segregation of tetrahedral units.
    • Table S1. Crystal data and structure refinement for Au40(o-MBT)24.
    • Table S2. Crystal data and structure refinement for Au52(TBBT)32.
    • Table S3. Atomic coordinates (×104) and equivalent isotropic displacement parameters (Å2 ×103) for Au40(o-MBT)24.
    • Table S4. Atomic coordinates (×104) and equivalent isotropic displacement parameters (Å2 × 103) for Au52(TBBT)32.
    • Table S5. Calculated atomic charges.

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