Specific features of formyl- and acetylferrocene oxidation with peroxides in water and organic solvents

Abstract

Specific features of formyl- and acetylferrocene oxidation with peroxides ROOR (R = H, tert-C4H9) in different solvents are studied. It is shown that despite of the presence in complexes of strong electronacceptor substituents they can be oxidized with hydrogen peroxide in the absence of strong Bronsted acids. Dilution of water with organic solvent leads to deceleration and complete standstill of the reaction. In the absence of acids the second order of the process with respect to peroxide and first one with respect to the metal complex was evaluated. In the presence of perchloric or trifluoroacetic acid the order with respect to peroxide decreases to the first one. The dependence of the reaction rate on the concentration of acid has an extremum point. The activity of other peroxides in the reaction with the above-mentioned compounds is significantly lower than the activity of hydrogen peroxide. Probable alternative mechanisms of oxidation of the abovementioned ferrocenes with hydrogen peroxide in the presence and in the absence of acids differing in the way of coordination of reagents with one another and considering direct participation of substituent in the oxidation is suggested.