Bottom-up Synthesis of Novel 3D Carbon-Allotropes, Derived from 6.8² P and 6.8² D Polybenzene

该项目的中心目标是开发获得分子构建块所需的合成方法，这些分子构建块可以组装成6.8² D和6.8² P聚苯的三维结构，这些结构可以添加到合成碳同素异形体（SCA）家族中。SCA如富勒烯，碳纳米管和石墨烯表现出巨大的高性能应用潜力，这就是为什么寻求新的碳基功能纳米材料是目前受到极大关注的主题。其中一种最好的形式是以聚苯（pbz）网络为代表。6.8² D和6.8² P两种可能的拼接结构，都是sp2杂化碳原子的三维拼接结构，只包含一种碳原子，它们以2：3的比例组装成六元环和八元环。由于连接性的不同，其结构、稳定性和电子特性有很大差异。而金属6.8² P聚苯具有与C60富勒烯相当的稳定性，并提供足够大的空腔以嵌入更大的离子（K+，Sr 2+，Br-）或甚至小分子（CO，N2，O2），间接半导体6.8² D聚苯比6.8² P网络更稳定，并表现出适合小离子封装的固有孔隙率（Li+、Na+、Mg2+）。我试图设计一个可扩展的合成和详细的表征的小分子积木环辛-1，3，5，7-四酮功能酮基，将允许一个控制的交联反应所需的三维碳网络。提出的这种关键前体的网状自组装是基于迭代的刘易斯或布朗斯特酸催化的烯醇化，然后是自缩合。在此，我将依赖于在水存在下羟醛缩合机制的可逆性，以促进对形成高度结晶样品至关重要的动态误差校正。为了实现化学稳定性较低的6.8² P聚苯瓦的开发，我打算利用依赖于非共价阳离子-π相互作用的模板辅助结晶方法。将使用同步加速器X射线衍射、透射电子显微镜和固态13 C NMR技术进行完整的结构表征。

The central goal of this project is to develop the synthetic methodologies required to access molecular building blocks that can be assembled into the three-dimensional structure of both 6.8² D and 6.8² P polybenzene which can be added to the family of synthetic carbon allotropes (SCA). SCAs such as fullerenes, carbon nanotubes and graphene exhibit enormous potential for high-performance application which is why the quest for new carbon-based functional nanomaterials is a topic that currently receives tremendous attention. One of the most auspicious form is represented by the polybenzene (pbz) network. The two possible tillings, 6.8² D and 6.8² P polybenzene, are both 3D tilings of sp² hybridized carbon atoms contain just a single type of carbon atom which assemble into six- and eight-membered rings in a ratio of 2:3. Due to the different connectivity, the structure, stability, and electronic characteristic differs much. While the metallic 6.8² P polybenzene has a stability comparable to C60 fullerene and provides cavities large enough for intercalation of bigger ions (K+, Sr2+, Br–) or even small molecules (CO, N2, O2), the indirect semiconductor 6.8² D polybenzene is significantly more stable than the 6.8² P network and exhibits an intrinsic porosity suitable for the encapsulation of small ions (Li+, Na+, Mg2+). I seek to design a scalable synthesis and a detailed characterisation of the small molecular building block cycloocta-1,3,5,7-teraone featuring functional keto-groups that will allow for a controlled cross-linking reaction to the desired 3D carbon-network. The proposed reticular self-assembly of this key precursor is based on iterative Lewis or Brønsted acid catalysed enolizations followed by self-condensations. I will herein rely on the reversibility of the aldol condensation mechanism in the presence of water to facilitate the dynamic error-correction essential to the formation of a highly crystalline sample. To realise the development of the thermodynamically less stable 6.8² P polybenzene tiling, I intend to take advantage of template assisted crystallisation methods relying on no-covalent cation-π interactions. Complete structural characterisation will be performed using synchrotron X-ray diffraction, transmission electron microscopy and solid state 13C NMR techniques.