Uncovering the 3d and 4d Electronic Interactions in Solvated Ru Complexes with 2p3d Resonant Inelastic X‑ray Scattering

The
electronic structure and dynamics of ruthenium complexes
are
widely studied given their use in catalytic and light-harvesting materials.
Here we investigate three model Ru complexes, [RuIII(NH3)6]3+, [RuII(bpy)3]2+, and [RuII(CN)6]4–, with L3-edge 2p3d resonant inelastic X-ray scattering
(RIXS) to probe unoccupied 4d valence orbitals and occupied 3d orbitals
and to gain insight into the interactions between these levels. The
2p3d RIXS maps contain a higher level of spectral information than
the L3 X-ray absorption near edge structure (XANES). This
study provides a direct measure of the 3d spin–orbit splittings
of 4.3, 4.0, and 4.1 eV between the 3d5/2 and 3d3/2 orbitals of the [RuIII(NH3)6]3+, [RuII(bpy)3]2+, and [RuII(CN)6]4– complexes, respectively.