Functional Nanoloops: Strain-Promoted Modification of Acetylene-Containing Cycloparaphenylenes

该项目旨在将环对苯撑（CPP）与反应性乙炔的高度热门研究领域合并，以提供功能化CPP衍生的纳米环库。由此产生的支架将深入研究其资格作为功能材料在有机electronics.The合成策略依赖于一个反应性的乙炔部分，嵌入CPP框架内，转化成相应的乙烯衍生物，通过环加成化学与合适的合作伙伴的应用。事实上，初步的密度泛函理论（DFT）的计算已经显示出一个显着减少的固有应变能从乙炔结合CPP到其乙烯同源物，这是预测提供显着的速率增强。应变促进的转化基于乙炔化学领域内的成熟反应，例如Diels-Alder、[2+2]-环加成-逆电环化或环三聚反应，其将允许将各种各样的官能部分引入大环CPP骨架中。这种方法将提供多功能的访问量身定制的纳米环具有吸引人的属性。所得化合物将用作有机发光二极管中的荧光组分或用于包封富勒烯型客体以促进能量/电子转移过程的大环主体。除此之外，含乙炔的CPP代表了在金属表面和溶液中形成共价2D网络的有价值的分子构建块。应变促进功能化方法将被应用于通过热活化在限定的金属表面上制造具有高结构精度的富碳2D聚合物。这些2D架构的制备和表征将通过DFT计算支持的扫描探针显微镜技术（STM和AFM）进行，以证实实验结果并更深入地了解电子特性和能带结构。不用说，这种多孔石墨纳米材料--高度热门但难以捉摸的目标--不仅对分子级传感器、膜和电子学至关重要，而且由于其独特的光电性质，也具有根本的科学兴趣。总之，该项目不仅解决了目前合成功能化CPP衍生实体的瓶颈，而且还为主体/客体研究和原子定义的2D纳米材料开辟了一条通向多功能大环结构单元的途径。因此，该项目的结果将为来自不同领域的其他研究人员提供一个基础和通用的工具，用于设计和合成具有定制光电和材料特性的前所未有的材料。

The project aims to merge the highly topical research fields of cycloparaphenylenes (CPPs) with reactive acetylenes, to afford a library of functionalized CPP-derived nanoloops. The resulting scaffolds will be studied in-depth concerning their qualification as functional materials for application in organic electronics.The synthetic strategy relies on the transformation of a reactive acetylene moiety that is embedded within the CPP framework, into its corresponding ethylene derivative through cycloaddition chemistry with suitable partners. Indeed, preliminary density functional theory (DFT) calculations have shown a significant reduction of the inherent strain energy on going from the acetylene-incorporating CPP to its ethylene congener, which is predicted to provide for significant rate enhancements. The Strain-promoted transformations are grounded on well-established reactions within the realm of acetylene chemistry, such as Diels-Alder, [2+2]-cycloaddition-retroelectrocyclization or cyclotrimerization reactions that will allow the introduction of a broad variety of functional moieties into the macrocyclic CPP backbone. This approach will provide versatile access to tailored nanorings with appealing properties. The resulting compounds will serve e.g. as fluorescent components in organic light-emitting diodes or macrocyclic hosts for encapsulation of fullerene-type guests to foster energy/electron transfer processes.Beyond that, the acetylene-containing CPPs represent valuable molecular building blocks for the formation of covalent 2D networks on metal surfaces and in solutions. The strain-promoted functionalization approach will be applied to fabricate such carbon-rich 2D polymers with high structural precision on defined metal surfaces through thermal activation. The preparation and characterization of these 2D architectures will be carried out by scanning probe microscopy techniques (STM and AFM) supported by DFT calculations to corroborate the experimental results and gain deeper insight into electronic properties and band structures. Needless to say, such porous graphitic nanomaterials – highly topical, yet elusive targets – are not only vital for molecular-scale sensors, membranes and electronics, but also of fundamental scientific interest owing to their unique optoelectronic properties.In summary, the project not only tackles the current bottleneck of synthetic accessibility of functionalized CPP-derived entities, but also opens up an avenue towards versatile macrocyclic building blocks for host/guest studies and atomically defined 2D nanomaterials. As such, the results of the project will provide a fundamental and versatile tool to other researchers from different fields for the design and synthesis of unprecedented materials with tailored optoelectronic and material properties.