Determination of kinetic parameters of 1,1′-diacylferrocene at a gold microdisc electrode

Abstract

Ferrocene and its derivatives have been widely studied by various physical methods because of their key role in the stimulation of the development of organometallic chemistry and material science [1-6]. They are valuable in organic and organometallic syntheses, for example in asymmetric synthesis, catalytic hydrogenation peptide synthesis etc.. They are also potential aids to the understanding of biological electron transfer and the design of molecular electronic devices. Their redox potential and kinetic parameters are helpful for selecting d o n o r / a c c e p t o r couples for the establishment of biomimetic membrane system. However, the absence of straightforward and reliable procedures for the determination of kinetics of heterogeneous electron transfer reactions with rate constants above 10 -4 m s -~ has long been a problem. In recent years, microelectrodes have become popular as a means of ameliorating this difficulty, especially when used in conjunction with voltammetry [1,5,7-12]. The most striking feature of microelectrodes is their extremely small surface areas which can both enhance the effective mass transport rate and reduce the potential drop in the resistive solution. In general, they exhibit sigmoidal vol tammograms at slow scan rates, which offers a number of advantages over the more familiar transient voltammetry. In this work we synthesized the ferrocene derivatives FcX2; the substituents are generally bonded to the cyclopentadienyl ring through a n sp 3 hybridized