ICMADS (In-situ Chemistry of Molecular Assemblies on Dielectric Surfaces)

近年来，表面化学的概念已被用于制造功能分子结构。这种方法开辟了创造热稳定性和化学稳定性结构的可能性，这是标准沉积和组装技术无法实现的。此外，将反应限制在两个维度上可能会出现在溶液中无法到达的新反应路线。到目前为止，已发表的涉及表面化学的实验仅限于金属表面，或者最近在NaCl/Ag单层上的一个例子（100）。在这个项目中，我们将探索在介电表面上创建分子结构的表面化学。两种根本不同的表面化学策略将在两个模型表面上进行研究，即氟化钙和方解石。首先，我们将探索在二酸、三酸或多氮杂化合物与金属原子共吸附的情况下，通过金属络合形成扩展结构。其次，我们将诱导自由基的共价偶联，这些自由基是通过碘芳烃分子的原位异裂解热裂解以及二硼酸和三硼酸与-二醇的酯化反应获得的。该项目包括设计和合成量身定制的分子，它们的活化和详细的表面和分子特征，通过使用可变温度非接触式扫描力显微镜以及紫外光电子和亚稳冲击电子能谱的直接成像。模拟将进行深入了解分子结构和确认反应途径。

Recently, the concept of on-surface chemistry has been exploited for fabrication of functional molecular structures. This approach opens up the possibility for creating thermally and chemically stable structures that cannot be achieved by standard deposition and assembly techniques. Moreover, confining the reaction in two dimensions may enable new reaction routes that are not accessible in solution. Published experiments involving on-surface chemistry have been limited to metallic surfaces so far, or in one recent example on a monolayer of NaCl/Ag(100). In this project we will explore on-surface chemistry for creating molecular structures on dielectric surfaces. Two fundamentally different strategies for on-surface chemistry will be investigated on two model surfaces, namely calcium fluoride and calcite. First, we will explore the formation of extended structures by metal-complexation upon co-adsorption of diacids, triacids or polyazaaromatics and metal atoms. Second, we will induce covalent coupling of radicals obtained by in-situ heterolytic thermal cleavage of molecules such as iodoaromatics and by esterification of di- and triboronic acids with alpha-diiols. The project includes the design and synthesis of tailor-made molecules, their activation and a detailed surface and molecular characterisation by direct imaging using variable-temperature non-contact scanning force microscopy as well as ultraviolet photoelectron and metastable impact electron spectroscopy. Simulations will be performed for gaining insights into the molecular structures and to confirm reaction pathways.