Hanna, Lauren. Spectroscopic interrogation of metal ligation and photoactive properties in metal-organic frameworks. Retrieved from https://doi.org/doi:10.7282/t3-bhxr-ws11
DescriptionMetal-organic frameworks (MOFs), a class of crystalline hybrid materials, have been studied for a variety of applications ranging from gas sorption to photocatalysis. While the topic of most MOF research focuses on the application of the material, it is important to first understand the structure-function relationship. The adsorption-based functionalities of porous metal-organic framework (MOF) materials that lead to applications such as catalysis and gas separation rely on specific host–guest interactions often involving open metal sites within the nodes of the framework. These interactions are difficult to probe on the molecular level and consequently poorly understood. Spectroscopic methods provide the necessary molecular level information on local metal coordination and electronic structure. In this thesis, steady-state and time resolved optical, x-ray, and vibrational spectroscopic methods are all used to gain molecular level insight, and sometimes a conjunction of techniques are needed to provide a comprehensive answer. Namely, valence-to-core X-ray emission spectroscopy has proven to be exceptionally sensitive to ligand identity, however, for a complete understanding of ligand identity and the nature of the interaction within a given framework, results were complimented with other spectroscopic methods such as Raman spectroscopy and X-ray absorption spectroscopy. Additionally, element specific techniques like X-ray spectroscopic methods, specifically X-ray transient absorption spectroscopy offer element specific excited state information that eludes assignment via convention methods. A brief summary of each chapter is provided below.