Spontaneous chiral resolution in supramolecular assembly of 2,4,6-tris(2-pyridyl)-1,3,5-triazine on Au(111).
Spontaneous chiral resolution in supramolecular assembly of 2,4,6-tris(2-pyridyl)-1,3,5-triazine on Au(111).
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DOI：
10.1021/ja9001986
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发表时间：
2009-04
影响因子：
15
通讯作者：
Jing Zhang;Bin Li;Xuefeng Cui;B. Wang;Jinlong Yang;Jianguo Hou
中科院分区：
文献类型：
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作者：
Jing Zhang;Bin Li;Xuefeng Cui;B. Wang;Jinlong Yang;Jianguo Hou
利用双真空低温扫描隧道显微镜研究了2，4，6-三（2-吡啶基）-1，3，5-三嗪（TPTZ）分子在Au（111）表面的自组装. TPTZ分子形成由菱形超晶胞组成的对映结构域，其具有取决于分子覆盖度的各种周期，即在低覆盖度下的“1 x 1”和“2 x 2”结构，以及在较高覆盖度下的“6 x 6”、“7 x 7”和“8 x 8”结构。在某一对映体的晶胞中，由吸附的TPTZ分子组成的两个三角形半晶胞彼此中心对称。每个半晶胞内的分子通过单个-CH相互结合。半晶胞之间的分子通过双-CH键结合，而半晶胞之间的分子则通过双-CH键结合。N-氢键。STM图像和密度泛函理论计算表明，在对映结构域中，TPTZ分子具有与R-TPTZ和L-TPTZ相同的吸附取向，表明TPTZ分子在Au（111）表面发生了自发手性拆分。分子间相互作用和分子-基底相互作用之间的微妙平衡调节了超结构的周期。从DFT计算得到的总相互作用能密度定量地解释了实验观察。
We have investigated the self-assembly of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) molecule on Au(111) surface using an ultrahigh vacuum low-temperature scanning tunneling microscope. The TPTZ molecules form enantiomorphous domains composed of rhombic supercells with various periods depending on the coverage of molecules, that is, "1 x 1" and "2 x 2" structures at low coverages, and "6 x 6", "7 x 7", and "8 x 8" structures at higher coverages. In a unit cell of a certain enantiomer, the two triangular half-unit cells, consisting of adsorbed TPTZ molecules, are centrosymmetric to each other. The molecules inside each half-unit cell are bound to each other through a single -CH...N- hydrogen bond, while the molecules at the boundaries between half-unit cells are bound through double -CH...N- hydrogen bonds. The STM images and the DFT calculations reveal that the molecules in an enantiomorphous domain adopt the same adsorption orientation of either R-TPTZ or L-TPTZ, which indicates that the adsorbed TPTZ molecules on Au(111) undergo spontaneous chiral resolution. The subtle balance between the intermolecular interaction and the molecule-substrate interaction tunes the period of the superstructure. The total interaction energy densities obtained from the DFT calculations explain the experimental observations quantitatively.