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

Structural and electronic characterization of (Cp′3Cm)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′3Cm displays unexpectedly low energy emission that is quenched upon coordination by 4,4′-bipyridine. Electronic structure calculations on Cp′3Cm and (Cp′3Cm)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′3Cm)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.