Mechanism of the photochemical reaction between ferrocene and iodine

Abstract

In benzene solution the photochemical reaction of iodine with ferrocene proceeds by three steps, namely (i) the photodissociation of I₂ to I atoms, (ii) the oxidation of ferrocene by an I atom (or an I· benzene charge-transfer complex) to produce the ferricenium iodide ion-pair and (iii) the reaction of ferricenium iodide with I₂ to yield the ferricenium tri-iodide ion-pair. Rate constants have been measured for processes (ii) and (iii) which indicate that the former is very near and the latter quite near the diffusion-controlled limit.