TY  - JOUR
A1  - Jay, Raphael M.
A1  - Vaz da Cruz, Vinicius
A1  - Eckert, Sebastian
A1  - Fondell, Mattis
A1  - Mitzner, Rolf
A1  - Föhlisch, Alexander
T1  - Probing solute-solvent interactions of transition metal complexes using L-edge absorption spectroscopy
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - In order to tailor solution-phase chemical reactions involving transition metal complexes, it is critical to understand how their valence electronic charge distributions are affected by the solution environment. Here, solute-solvent interactions of a solvatochromic mixed-ligand iron complex were investigated using X-ray absorption spectroscopy at the transition metal L-2,L-3-edge. Due to the selectivity of the corresponding core excitations to the iron 3d orbitals, the method grants direct access to the valence electronic structure around the iron center and its response to interactions with the solvent environment. A linear increase of the total L-2,L-3-edge absorption cross section as a function of the solvent Lewis acidity is revealed. The effect is caused by relative changes in different metal-ligand-bonding channels, which preserve local charge densities while increasing the density of unoccupied states around the iron center. These conclusions are corroborated by a combination of molecular dynamics and spectrum simulations based on time-dependent density functional theory. The simulations reproduce the spectral trends observed in the X-ray but also optical absorption experiments. Our results underscore the importance of solute-solvent interactions when aiming for an accurate description of the valence electronic structure of solvated transition metal complexes and demonstrate how L-2,L-3-edge absorption spectroscopy can aid in understanding the impact of the solution environment on intramolecular covalency and the electronic charge distribution.
KW  - basis-sets
KW  - charge-transfer
KW  - density
KW  - dynamics
KW  - electron localization
KW  - iron
KW  - solvation
KW  - spin-crossover
KW  - tranfer excited-state
KW  - x-ray-absorption
Y1  - 2020
U6  - https://doi.org/10.1021/acs.jpcb.0c00638
SN  - 1520-6106
SN  - 1520-5207
VL  - 124
IS  - 27
SP  - 5636
EP  - 5645
PB  - American Chemical Society
CY  - Washington
ER  -