In continuation of our collaboration with Prof. Emad F. Aziz and Dr. Igor Yu. Kiyan from Helmholtz-Zentrum in Berlin, a new investigation has been recently published. In this study, we address the early photodynamics of ferricyanide ion in solution applying transient XUV photoelectron spectroscopy in tandem with theoretical modeling.
Phys. Chem. Chem. Phys., 2017,19, 14248-14255 Light-induced relaxation dynamics of the ferricyanide ion revisited by ultrafast XUV photoelectron spectroscopy
This combination has been already applied by us to unravel peculiarities of spin crossover in [Fe(bpy)3]2+ complex. Here, we have addressed the problem of charge localization and symmetry-breaking in the simple prototypical coordination compound – ferricyanide. Upon absorption of UV light, it is excited to the charge-transfer state, which can undergo non-radiative relaxation to the ground state or be involved in further chemical reactions. This is a usual trait of coordination and organometallic compounds, which is often used by nature and chemists in, e.g., photosynthesis or photocatalytic retrieval of ecologic fuels.
In previous UV pump – IR probe spectroscopic study of the photochemical fate of ferricyanide, it was concluded that the initially populated charge-delocalized state relaxes to the localized one and the process is driven by the reorganization of the polar solvent. However, we obtained strong evidence for the spin crossover followed by geometrical distortions due to Jahn–Teller effect, rather than localization/delocalization dynamics, as suggested previously. Remarkably, our interpretation also consistently explains the transient features observed in UV-IR pump-probe experiments along with transient XUV PES.