Probing f‑Block Covalency at the Limits of Hard-Metal/Soft-Ligand Interactions through Chalcogenoether Complexes

We report a systematic probe of covalency at the boundaries of f-block hard-metal/soft-ligand interactions by employing monoanionic ligands containing formally neutral chalcogen donors to facilitate isostructural comparisons of early to middle trivalent actinides (An = U, Np, Pu, Am) and their near isoradial lanthanide counterparts (Ln = La, Ce, Pr, Nd). The single-crystal structural data on [(AE₂^Ph2)₂M^IIII] (1-M, E = S, M = La, Ce, Pr, Nd, U, …