On-Surface Synthesis of Linear Polyphenyl Wires Guided by Surface Steric Effect
On-Surface Synthesis of Linear Polyphenyl Wires Guided by Surface Steric Effect
复制标题
表面空间效应引导线性聚苯线材的表面合成
DOI：
10.1021/acs.jpcc.6b00284
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发表时间：
2016-03-31
影响因子：
3.7
通讯作者：
Zhong, Dingyong
中科院分区：
文献类型：
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作者：
Cai, Zeying;She, Limin;Zhong, Dingyong
在原子尺度上剪裁功能化纳米结构在纳米技术中具有重要意义。我们报道了通过对六苯基（p-6 P）在各向异性Au（110）表面上的直接C-H活化和C-C偶联来可控制造线性聚苯线。由于表面的一维空间限制，p-6 P分子的等效C-H键随着不同的反应概率而有所不同。因此，p-6P的线性聚合是通过间位上的C-C键实现的，每6个亚苯基单元形成一个扭结。另一方面，支化聚合被有效地抑制。在这些扭结的聚苯线，反式构象是占主导地位的，相比顺式构象。此外，排他性的C-C键的形成在p-6P对位已被相邻的三联苯自由基，它具有反应性对位网站，从而导致形成直的parapolyphenyl线，而不是扭结的。我们的研究表明，表面位阻效应可以应用于引导表面合成的途径朝向所需的共价键合的纳米结构。
Tailoring functionalized nanostructures at the atomic scale is of importance in nanotechnology. We report on the controllable fabrication of linear polyphenyl wires by direct C-H activation and C-C coupling of para-sexiphenyl (p-6P) on an anisotropic Au(110) surface. Because of the one-dimensional spatial constraint at the surface, the equivalent C-H bonds of p-6P molecules were differentiated with various reaction probabilities. Consequently, linear polymerization of p-6P was achieved via C-C bonding at the meta-sites, with the kink formation every 6 phenylene units. On the other hand, branched polymerization was efficiently suppressed. Among such kinked polyphenyl wires, the trans conformation is predominant, compared with the cis conformation. Furthermore, exclusive C-C bond formation at the p-6P para-sites has been promoted by the neighboring terphenyl radicals, which possess reactive para-sites, resulting in the formation of straight parapolyphenyl wires instead of kinked ones. Our study demonstrates that the surface steric effect can be applied to guide the pathway of on-surface synthesis toward desired covalently bonded nanostructures.