Novel Synthetic Design and Methods for Atomically Precise Nanographenes

由于其无与伦比的光电特性，原子精密纳米石墨烯及其相关结构在化学和材料科学的几个领域获得了重要的意义。然而，由于缺乏合成方法，几种非常有前途的结构还不能有效地制备，因此它们的全部潜力尚未得到开发。我们研究项目的核心目标是开发创新和通用的合成工具，用于制备前所未有的、定义明确的纳米石墨烯（ng）、石墨烯纳米带（gnr）和具有独特物理性质的碳同素异形体。本提案分为四个相关主题：分子内C-C偶联的无金属光化学反应2. gnr和其他一维碳同素异形体；3. 锯齿形边缘的NGs和gnr；4. 具有高双自由基性质的共轭分子。作为一个中短期项目，我们将继续致力于开发和研究一种称为环脱氢氯化反应（CDHC）的反应，以制备不同拓扑结构的NGs， gnr和新的碳同素异形体。我们的中长期目标将是使用这种方法制备受欢迎的扶手椅gnr的前所未有的拓扑结构，其合成尚不可能使用已知的湿化学策略。此外，还将制备低带隙、具有5元环和7元环的一维碳同素异形体。最佳候选材料将作为有机电子器件的活性材料集成。另一个中期目标是制备长、稳定、带隙小的锯齿边纳米石墨烯。我们提出了一种创新的方法，包括使用短的，稳定的锯齿状边缘分子，如萘和芘，作为构建块来制备更长的类似物。将采用不同的合成方法制备短的定长模型化合物，以研究其稳定性及其结构和性质之间的关系。我们的长期目标是合成锯齿边gnr并评估其单线态裂变特性。纳米碳纳米管和纳米碳纳米管将被用作制备高双自由基分子的支架。我们建议在不同的ngg和gnr中“按需”生成双自由基，通过与芳香骨架内的金属进行配位化学，利用可调节的空间位阻。利用我们的创新方法所取得的发现将对物理有机化学和材料科学产生重大影响。这项研究计划基于我们在芳香化合物领域的长期专业知识，完全符合我们的长期目标，即获得非正统的富碳分子和材料，这些分子和材料可以超越电子应用中最知名的材料。

Atomically precise nanographenes and related structures have gained significant importance in several areas of chemistry and materials science due to their unmatched optoelectronic properties. Yet, their full potential has not yet been exploited as several types of very promising structures cannot yet be prepared efficiently due to the lack of synthetic methods. The central objective of our research program is to develop innovative and versatile synthetic tools for the preparation of unprecedented, well-defined nanographenes (NGs), graphene nanoribbons (GNRs) and carbon allotropes with unique physical properties. This proposal is separated into four related themes: 1. Metal-free photochemical reaction for intramolecular C-C coupling; 2. GNRs and other one-dimensional carbon allotropes; 3. Zigzag-edged NGs and GNRs; 4. Conjugated molecules with a high diradical character. As a short- to medium-term project, we will pursue our efforts in the development and study of a reaction called the cyclodehydrochlorination (CDHC) for the preparation of NGs, GNRs and new carbon allotropes of different topologies by following three strategies. Our medium- to long-term goal will be to use this method to prepare unprecedented topologies of sought-after armchair GNRs whose synthesis is not yet possible using known wet chemistry strategies. Also, low bandgap, one-dimensional carbon allotropes with 5- and 7-membered rings will be prepared. The best candidates will be integrated as active materials in organic electronics devices. Another medium-term objective is to prepare long, stable zigzag-edged nanographenes with low bandgap. We propose an innovative approach that consists of using short, stable zigzag-edged molecules, such as naphthalene and pyrene, as building blocks to prepare longer analogs. Short, definite-length model compounds will be prepared using different synthetic approaches to study their stability and the relationships between their structures and properties. Our long-term goal is to synthesize zigzag-edged GNRs and evaluate their singlet fission properties. NGs and GNRs will be used as scaffolds to prepare molecules with a high diradical character. We propose to generate diradicals "on demand" in various NGs and GNRs by using tunable steric hindrance through coordination chemistry with metals within the aromatic skeleton. The discoveries that will be made using our innovative approaches will have a significant impact on physical organic chemistry and materials science. This research program is based on our long-standing expertise in the area of aromatic compounds and fits perfectly with our long-term objective, which is to have a access to unorthodox carbon-rich molecules and materials that could surpass the best-known materials in electronics applications.