Low oxidation state actinide heterolide complexes

点击翻译按钮获取中文摘要

This project seeks to develop the chemistry of low oxidation state (OS) actinide (An2+ and An3+) ions towards a deeper understanding of the properties that affect their valence electron configuration (VEC), bonding, and reactivity, and the potential for divergent chemistry driven by different VECs. Contemporary low OS, actinide chemistry has defined two classes of An2+ and An3+ ion where the VEC can be described using the following two formalisms: fn+1 or fnd1 (note that these simply describe an approximation of the configuration of the outermost electrons in these ions). In some cases both exist for the same metal with different coordination environments. Here we will exploit a modular molecular design to target low OS actinide An ions using soft donor ligands which allow a single variable (the identity of a heteroatom) can be changed with minimal changes to the coordination environment. This will afford unprecedented insight into the physicochemical properties of these ions, and the factors which govern their stabilities. We will achieve this by:1) synthesising low OS f-block complexes using modular frameworks where ligand donor atoms can be altered with minimal changes to the overall stereochemical properties; 2) using donor elements which are amenable to advanced spectroscopic characterisation;3) characterising molecules by magnetism (SQUID), magnetic resonance (NMR, EPR), X-ray absorption spectroscopy (at metal edges), to deepen understanding of their electronic structure. This systematic approach has not yet been applied to this nascent research area and is a logical next step to expand its frontier. This work will produce fundamental knowledge to inform future work into configuration control of f-block ions, and redox-driven lanthanide/actinide chemistry.Questions:Can we use novel soft-donor ligands to isolate low-oxidation state and actinide complexes?What is the electronic structure of these complexes, does the electron density reside on the metal or ligand?Does this change with the donor type?Do these low oxidation state complexes react like traditional actinide complexes, or more like transition metals?Approach:Design and synthesize ligands.Make complexes in readily available oxidation states.Reduce complexes to lower formal oxidation states.Characterize using state of the art experimental and theoretical approaches.Study reactivity using classical transition metal reaction classes.Remit / themes:Synthetic coordination chemistry/Computational and theoretical chemistry.Condensed matter: electronic structure.Condensed matter: magnetism and magnetic materials.