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.