On-surface synthesis has emerged as a powerful approach to the atomically precise fabrication of molecular architectures with potential applications in nanotechnology. However, it is challenging to synthesize molecular structures that can protrude from the surface such as polymer chains forming by the molecules with upright conformations, since most of the on-surface reaction products, particularly the conjugated structures, prefer to adsorb parallel on the surface to maximize the molecule–substrate interaction. Here, we show an up-standing phenanthrene polymer chain with an all-cis configuration obtained by on-surface synthesis upon highly selective C–H activation. Using bond-resolved nc-AFM imaging, the reaction route of polymers from an in-plane to an all-cis upright conformation is fully characterized, and the reaction mechanism is further revealed in combination with first principles calculations. Our results on this selective dehydrogenation induced upright-oriented polymer chains that will enrich the toolbox for the on-surface synthesis of novel molecular structures and may provide new insights on designing optimized precursors for preparing three-dimensional molecular frameworks through on-surface synthesis.

中文翻译：

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选择性CH键活化后，全顺式立构菲聚合物的表面合成。

表面合成已经成为原子结构分子精确制造的有力方法，并在纳米技术中具有潜在的应用。但是，合成可能从表面突出的分子结构（例如由具有直立构象的分子形成的聚合物链）具有挑战性，因为大多数表面反应产物（尤其是共轭结构）更喜欢在表面平行吸附，最大化分子与底物的相互作用。在这里，我们显示了通过高度选择性的C–H活化通过表面合成获得的具有全顺式构型的长寿菲聚合物链。使用键分辨的nc-AFM成像，可以充分表征聚合物从平面内到全顺式直立构象的反应路线，结合第一性原理计算，进一步揭示了反应机理。我们关于这种选择性脱氢的结果诱导了直立定向的聚合物链，这将丰富用于新型分子结构的表面合成的工具箱，并可能为设计优化的前体以通过表面合成制备三维分子框架提供新的见解。