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所需的合成方法，以获得可以组装成6.8²D和6.8²P多苯的三维结构的分子构建块，这些结构可以添加到合成碳同素异形体（SCA）家族中。富勒烯、碳纳米管和石墨烯等SCAs在高性能应用方面表现出巨大的潜力，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话题。最吉祥的一种形式是以多苯（pbz）网络为代表的。两种可能的铺层，6.8²D和6.8²P多苯，都是sp²杂化碳原子的三维铺层，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。由于连接方式的不同，结构、稳定性和电子特性都有很大的不同。虽然金属6.8²P多苯具有与C60 fullerene相当的稳定性，并且提供足够大的空腔来嵌入较大的离子（K+, Sr2+, Br -）甚至小分子（CO, N2, O2），但间接半导体6.8²D多苯比6.8²P网络稳定得多，并且具有适合封装小离子（Li+, Na+, Mg2+）的固有孔隙。我试图设计一种可扩展的合成方法，并详细描述具有功能酮基的小分子构建块环-1,3,5,7-太龙，这将允许与所需的3D碳网络进行可控的交联反应。该关键前驱体的网状自组装是基于迭代Lewis或Brønsted酸催化的烯化反应，然后是自缩聚。在此，我将依靠存在水的醛醇缩合机制的可逆性来促进对形成高结晶样品必不可少的动态误差校正。为了实现热力学不稳定的6.8²P聚苯瓷砖的发展，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。完整的结构表征将使用同步加速器x射线衍射，透射电子显微镜和固态13C核磁共振技术进行。

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.