We demonstrate a family of molecular precursors based on 7,10-dibromo-triphenylenes that can selectively produce different varieties of atomically precise porous graphene nanomaterials through the use of different synthetic environments. Upon Yamamoto polymerization of these molecules in solution, the free rotations of the triphenylene units around the C–C bonds result in the formation of cyclotrimers in high yields. In contrast, in on-surface polymerization of the same molecules on Au(111) these rotations are impeded, and the coupling proceeds toward the formation of long polymer chains. These chains can then be converted to porous graphene nanoribbons (pGNRs) by annealing. Correspondingly, the solution-synthesized cyclotrimers can also be deposited onto Au(111) and converted into porous nanographenes (pNGs) via thermal treatment. Thus, both processes start with the same molecular precursor and end with a porous graphene nanomaterial on Au(111), but the type of product, pNG or pGNR, depends on the specific coupling approach. We also produced extended nanoporous graphenes (NPGs) through the lateral fusion of highly aligned pGNRs on Au(111) that were grown at high coverage. The pNGs can also be synthesized directly in solution by Scholl oxidative cyclodehydrogenation of cyclotrimers. We demonstrate the generality of this approach by synthesizing two varieties of 7,10-dibromo-triphenylenes that selectively produced six nanoporous products with different dimensionalities. The basic 7,10-dibromo-triphenylene monomer is amenable to structural modifications, potentially providing access to many new porous graphene nanomaterials. We show that by constructing different porous structures from the same building blocks, it is possible to tune the energy band gap in a wide range.

中文翻译：

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由同一分子前体选择性合成的多孔纳米石墨烯、石墨烯纳米带和纳米多孔石墨烯


我们展示了一系列基于 7,10-二溴三亚苯的分子前体，它们可以通过使用不同的合成环境选择性地生产不同种类的原子级精确的多孔石墨烯纳米材料。在溶液中对这些分子进行山本聚合时，三亚苯单元围绕 C-C 键自由旋转，导致高产率形成环三聚体。相反，在 Au(111) 上相同分子的表面聚合中，这些旋转受到阻碍，并且偶联继续形成长聚合物链。然后可以通过退火将这些链转化为多孔石墨烯纳米带（pGNR）。相应地，溶液合成的环三聚体也可以沉积在Au(111)上，并通过热处理转化为多孔纳米石墨烯(pNGs)。因此，这两个过程都以相同的分子前体开始，并以 Au(111) 上的多孔石墨烯纳米材料结束，但产物的类型（pNG 或 pGNR）取决于具体的偶联方法。我们还通过在高覆盖率下生长的 Au(111) 上高度排列的 pGNR 横向融合来生产扩展纳米多孔石墨烯 (NPG)。 pNGs 也可以通过环三聚体的 Scholl 氧化环化脱氢直接在溶液中合成。我们通过合成两种 7,10-二溴苯并菲，选择性地产生六种不同尺寸的纳米多孔产品，证明了这种方法的通用性。基本的 7,10-二溴苯并菲单体易于进行结构修饰，有可能为许多新型多孔石墨烯纳米材料提供途径。我们表明，通过用相同的构建块构建不同的多孔结构，可以在很宽的范围内调整能带隙。