Coordination States of Fe3+ and Fe2+ Dissolved in Organic Solvents

We spectroscopically investigated the coordination states of Fe2+ and Fe3+ dissolved in several organic solvents. Ultraviolet-visible (UV-vis) spectra and extended X-ray absorption fine structure (EXAFS) analyses revealed that Fe3+ forms [FeCl4](-) complex in all the solutions. The EXAFS analysis suggests that Fe2+ forms [FeCl4](2-) in N,N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP) solutions while it forms [FeL6](2+) (L is solvent molecule) in ethylene glycol (EG) and methanol (MeOH) solutions. We interpreted the solvent dependence of the Fe2+ coordination state in terms of the L-Fe2+ interaction and Cl- solubility in solvent.

Automated summary

In this study, the coordination states of Fe2+ and Fe3+ in organic solvents were investigated using spectroscopic techniques. The results showed that Fe3+ formed [FeCl4](-) complex in all the solutions, while Fe2+ formed different coordination structures in different solvents.