Developing x-ray spectroscopic method for f-element bond covalency

Recently, there is an increased interest in evaluating bond covalency in 4f element complexes. Bond covalency refers to the degree of electron sharing between a metal ion and surrounding ligands. A higher degree of covalency implies greater sharing of electrons, leading to stronger bonds and potentially influencing important properties such as chemical reactivity and luminescence or magnetism behavior. Herein, we develop spectroscopic methods based on high energy resolution X-ray absorption near edge structure and x-ray emission spectroscopy (HR-XANES, HR-XES) to investigate f-element bond covalency both at the experimental level at the KIT Light Source, KIT, Germany and theoretical ligand-field and density-functional theory level. We demonstrate that advanced spectroscopic tool at lanthanide L3-edge, including core-to-core Resonant Inelastic x-ray Scattering (RIXS), HR-XANES, and valence-band RIXS is sensitive to both the 4f and 5d valence orbitals, and allows us to investigate their levels of delocalization in a chemical bond. The spectroscopic method is applied to a large panel of lanthanide complexes at various oxidation states (II, III and IV) including inorganic salt as well as organometallics compounds, allowing us to achieve a reliable characterization of the lanthanide bonding properties. ... mehrThis presentation also contains description of procedures for sample preparation and transport of air-sensitive organometallics samples to ensure their integrity and stability before and during the experiment.