X-ray spectroscopic study of solvent effects on the ferrous and ferric hexacyanide anions

J Phys Chem A. 2014 Oct 9;118(40):9411-8. doi: 10.1021/jp5055588. Epub 2014 Sep 25.

Abstract

We present an Fe Kα resonant inelastic X-ray scattering (RIXS) and X-ray emission (XES) study of ferrous and ferric hexacyanide dissolved in water and ethylene glycol. We observe that transitions below the absorption edge show that the solvent has a distinct effect on the valence electronic structure. In addition, both the RIXS and XES spectra show a stabilization of the 2p levels when dissolved in water. Using molecular dynamics simulations, we propose that this effect arises from the hydrogen-bonding interactions between the complex and nearby solvent molecules. This withdraws electron density from the ligands, stabilizing the complex but also causing a slight increase in π-backbonding.