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.