Molecule-Oxide Bond Formation

有机/氧化物界面的基于知识的设计需要对分子-氧化物键的形成有详细的见解。在与funCOS伙伴项目的密切合作下，funCOS 3旨在通过将两种互补的表面光谱，即振动光谱(红外反射吸收光谱)和光电子光谱(也使用同步辐射的X射线光电子光谱，近边X射线吸收精细结构)与其他方法相结合，提供这一信息。从超高真空(UHV)的研究开始，我们将通过探索常压和液体环境中的锚定反应(漫反射红外傅里叶变换光谱、偏振调制红外光谱、近环境压力XPS、电化学红外反射吸收光谱)来弥合理想条件和实际条件之间的差距。此外，我们将直接将超高压实验与在液体环境中进行的反应性研究和光谱分析相结合。FunCOS3提供的关键信息包括反应机理、成键几何结构、能量、动力学和成键的可逆性。在第一个资助期，我们探索了分子锚定的基本方面，使用了简单的模型表面、小的测试分子和简单的卟啉衍生物。在此基础上，该项目现在将进入下一步，探索复杂的分子、纳米结构表面和现实环境。我们将把我们的注意力从氧化镁(100)转移到更复杂的氧化钴(Co3O4，CoO)和二氧化钛(Ti02)的案例上，这是探索从超高真空到液体环境中分子锚定的理想测试案例。具体地说，我们将针对五个关键挑战：(1)将知识和方法从小测试分子转移到功能化的卟啉衍生物。利用我们在羧酸盐锚定方面的专业知识，我们将调整取代模式，使用多个锚定或使用螯合锚定来控制分子取向、形成动力学和稳定性。(2)探索水在分子锚定中的作用。从识别锚定薄膜中质子和羟基的UHV研究开始，我们将研究H2O对键形成的影响，最后将这些研究与常压和液体环境下的光谱分析联系起来。(3)基于我们在羧酸锚定方面的综合工作，我们将探索可用于调节分子-表面相互作用(磷酸、异羟肟酸、羟基、邻苯二酚)的替代锚定。(4)我们将探索通过取代和金属化(通过芳香和空间相互作用、极性基团、氢键、金属配位)来独立调节分子间和分子-表面相互作用的概念。(5)最后，我们将利用这一知识来探索对纳米结构氧化物的选择性锚定，例如通过使用具有特定表面结构的锚定的选择性相互作用。

The knowledge-based design of organic/oxide interfaces requires detailed insights into molecule-oxide bond formation. In close collaboration with its funCOS partner projects, funCOS 3 aims at providing this information, by combining two complementary surface spectroscopies, namely vibrational spectroscopy (infrared reflection absorption spectroscopy) and photoelectron spectroscopy (X-ray photoelectron spectroscopy using also synchrotron radiation, near edge X-ray absorption fine structure), in combination with other methods. Starting from studies in ultrahigh vacuum (UHV), we will bridge the gap between ideal and real conditions by exploring anchoring reactions at ambient pressure and in liquid environments (diffuse reflectance infrared Fourier transform spectroscopy, polarization-modulation IRAS, near ambient pressure XPS, electrochemical infrared reflection absorption spectroscopy). In addition, we will directly couple UHV experiments to reactivity studies and spectroscopy performed in liquid environments. The key information provided by funCOS 3 comprises reaction mechanisms, bonding geometries, the energetics, the kinetics, and the reversibility of bond formation. In the first funding period, we explored the fundamental aspects of molecular anchoring, using simple model surfaces, small test molecules, and simple porphyrin derivatives. Building on this foundation, the project will now take the next step and explore complex molecules, nanostructures surfaces, and realistic environments. We will shift our attention from MgO(100) towards the more complex cases of cobalt oxide (Co3O4, CoO) and titanium dioxide (TiO2), ideal test cases to explore molecular anchoring from UHV to liquid environments. Specifically, we will target five key challenges: (1) We will transfer knowledge and methods from small test molecules to functionalized porphyrin derivatives. Using our expertise with carboxylate anchors, we will tune substitution patterns, use multiple anchoring or employ chelating anchors to control the molecular orientation, the formation kinetics, and the stability. (2) We will explore the role of water in molecular anchoring. Starting from UHV studies to identify protons and OH groups in the anchored film, we will investigate the influence of H2O on bond formation and, finally, link these studies to spectroscopy at ambient pressure and in liquid environments. (3) Based on our comprehensive work on carboxylate anchors, we will explore alternative anchors to tune molecule-surface interactions (phosphonic acid, hydroxamic acid, hydroxyl, catechol). (4) We will explore concepts to tune intermolecular and molecule-surface interactions independently by substitution and metalation (by aromatic and steric interactions, polar groups, H bonds, metal coordination). (5) Finally, we will use this knowledge to explore selective anchoring to nanostructured oxides, e.g. by employing selective interactions of anchors with specific surface structures.