Altering the spectroscopy, electronic structure, and bonding of organometallic curium(III) upon coordination of 4,4′−bipyridine

Structural and electronic characterization of (Cp′ 3 Cm) 2 ( μ −4,4′−bpy) (Cp′ = trimethylsilylcyclopentadienyl, 4,4′−bpy = 4,4′−bipyridine) is reported and provides a rare example of curium−carbon bonding. Cp′ 3 Cm displays unexpectedly low energy emission that is quenched upon coordination by 4,4′−bipyridine. Electronic structure calculations on Cp′ 3 Cm and (Cp′ 3 Cm) 2 ( μ −4,4′−bpy) rule out significant differences in the emissive state, rendering 4,4′−bipyridine as the primary quenching agent. Comparisons of (Cp′ 3 Cm) 2 ( μ −4,4′−bpy) with its samarium and gadolinium analogues reveal atypical bonding patterns and electronic features that offer insights into bonding between carbon with f -block metal ions. Here we show the structural characterization of a curium−carbon bond, in addition to the unique electronic properties never before observed in a curium compound. Despite the distinct electronic properties of the wide variety Cm3+ compounds that have been prepared to date, no singlecrystal structural characterization of a complex containing a Cm−C bond has been reported. Here the authors report the synthesis of a Cm complex bearing trimethylsilylcyclopentadienyl and 4,4’-bipyridine ligands with a low energy emission and identify the 4,4’-bipyridine ligand as the primary quenching agent.