Actinide (An) chemistry is one of the great fundamental challenges in inorganic chemistry especially since An-chalcogen binding is relatively unexplored. The complicated nature of the valence f-orbitals, partial shielding of these valence orbitals by previously filled s and p orbitals, and small difference in energy between the 5f and 6d orbitals leads to chemical and physical properties that are unique in the periodic chart. A solution is to look at coordination compounds with chalcogenolate (-ER: E = S, Se; R = organic) and chalcogenido (S or Se) ligands as probes to understand the nature of An-E bonds. We have synthesized four thorium chalcogenido clusters, (py)8Th4Se4(SePh)8 (1), (py)8Th4S4(SPh)8 (2), (py)8Th4S4(SePh)8 (3), and (py)8Th4Se4(SPh)8 (4) from ligand based redox reactions of elemental E with Th(EPh)4. All four compounds adopt a distorted cubane core structure with four Th(IV) and four chalcogenido µ3-E atoms. There are four bridging, µ2-EPh and four terminal, η-EPh chalcogenolate ligands in each structure. The compounds are structurally characterized via single-crystal X-ray diffraction and crystalize in the P212121, C2/c, C2/c and I4 space groups respectively. In pyridine solution of the Se derivatives all three chalcogen containing ligands were revealed by 77Se NMR studies and are in agreement with previously published Se NMR dataThermolysis of the heterochalcogen compounds [(py)2ThS(SePh)2]4 [(py)2ThSe(SPh)2]4 was performed at various temperatures and the solid state products are under investigation. to the new cluster materials can be in potential interest as probes to understand the nature of An-E bonds used in many separation technologies. Additionally, as energy demands increase, many look to thorium (Th) as a fuel source, and thus are interested in new ways to arrive at solid state chalcodenides.

Novel impact in actinide chemistry: Thorium sulfido and selenido compounds

254th National Meeting (2017)

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