Rational Synthesis of non-classical Nanographenes via Cyclodehydrofluorination Algorithm

对非经典纳米结构(含有非六角环、多螺旋和/或多孔体系的超大多环芳烃)的巨大兴趣源于对这些材料在下一代技术和未来电子学中可能应用的巨大期望。然而，研究和广泛应用仍然是难以捉摸的，因为仍然缺乏对这类分子的便捷访问。因此，为这类独特的材料开发新的有效的合成方法似乎是该领域的中心任务。该项目的目的是开发基于C-F键活化方法的非经典NGS的简便合成路线。所提出的策略依赖于本课题组开发的高效的芳基-芳基偶联技术(CDHF)。以前我们已经发现，在温和的条件下，分子内的芳基-芳基偶联可以通过热激活氧化铝上的C-F键有效地实现。在第一阶段，我们已经成功地证明了我们的方法用于合成纳米级和应变测地线系统的可行性，包括功能巴氏碗和富勒烯。在高选择性和频繁的定量转换中，CDHF提供了通过执行合理地内置到前体耦合算法中的多米诺骨牌式耦合(HF-Zipping)的可能性。这为前体的设计提供了必要的灵活性，并允许通过一锅分子内组装取代传统的逐步构建碳骨架的方法。由于我们在实现多重CDHF算法的纳米结构合成方面取得了巨大的成功，我们打算进一步研究这一反应，并开发一种通用的合成方法来合成各种非经典的NGS。我们的初步结果表明，简单地结合非六角环和构建多螺旋NGS是可行的。这为以完全可控的方式制备这些独特的材料指明了道路。本项目旨在通过C-F键活化合成螺旋形、碗形(含五角形)和马鞍形(含七角形/八角形)NGS。这包括合成合理的氟化前驱体，然后压缩成所需的纳米结构。我们计划用光谱和电化学方法来研究各自的非经典NGS。在这个项目的许多有趣的方面中，它打算进一步研究金属氧化物介导的缩合的机制。CDHF前所未有的高效率展示了这一提议的巨大潜力，并为实现这一提议的目标提供了强有力的基础。前期工作为解决难以捉摸的非经典NGs的简单合成这一挑战开辟了前景。

The exploding interest in non-classical nanographenes (extra-large PAHs containing non-hexagonal rings, multihelical and/or porous systems) originates from enormous expectations about the possible applications of these materials in the next generation technologiesand future electronics. However the investigation and widespread application have remained elusive since facile access to this class of molecules is still lacking. Therefore the development of new effective synthetic approaches to this unique class of materials appears to be the central task in the field. The aim of this project is to develop facilesynthetic routes to non-classical NGs based on the C-F bond activation approach. The proposed strategy is rely on highly effective Aryl-Aryl coupling technique via cyclodehydrofluorination (CDHF) developed in our group. Previously we have found that intramolecular Aryl-Aryl coupling can be realized effectively under mild conditions via C-F bond activation on thermally activated aluminum oxide. During the first period we have successfully demonstrated the feasibility of our approach for the synthesis of nanographenes and strained geodesic systems including functional buckybowls and fullerenes. Among the high selectivity and frequently quantitative Transformation the CDHF provides the possibility to perform a domino-like coupling(HF-zipping) via execution of the rationally built into a precursor coupling algorithm. This provides essential flexibility in the design of the precursor and allow superseding the conventional step-by-step construction of the carbon-skeleton by the one-pot intramolecularassembly. Because of our big success in the synthesis of nanostructures implementing multiple CDHF algorithm we intend to investigate this reaction further and to develop a general syntheticapproach to various non-classical NGs. Our preliminary results Show that facile incorporation of non-hexagonal rings and construction of multihelical NGs is feasible. This points the way to the preparative fabrication of these unique materials in a fully controllable manner. In this project the synthesis of helical, bowl-shaped (Pentagon containing) and saddle-shaped (heptagon/octagon containing) NGs via C-F bond activation is intended. This includes the synthesis of rationally fluorinated precursors followed by zipping to the desired nanostructures. The respective non-classical NGs are planned to be investigated with spectroscopic and electrochemical methods. Among many further interesting aspects of this project it is intended to investigate the mechanism of metal-oxide mediated condensationfurther. The unprecedentedly high efficiency of CDHF demonstrates the high potential and provides strong basis for achieving the objectives of this proposal. The preliminary work opens up promising vistas for tackling the challenge of facile synthesis of elusive nonclassicalNGs.