Ricerc@Sapienza

An innovative approach aimed at disclosing the mechanism of chemical
reactions occurring in solution on the millisecond time scale is presented. Time-resolved
energy dispersive X-ray absorption and UV/vis spectroscopies with millisecond resolution
are used simultaneously to directly follow the evolution of both the oxidation state and the
local structure of the metal center in an iron complex. Two redox reactions are studied, the
former involving the transformation of FeII into two subsequent FeIII species and the latter
involving the more complex FeII?FeIII?FeIV?FeIII sequence. The structural modifications
occurring around the iron center are correlated to the reaction mechanisms. This
combined approach has the potential to provide unique insights into reaction mechanisms
in the liquid phase and represents a new powerful tool to characterize short-lived
intermediates that are silent to common spectroscopic techniques.