Redox-active ferrocenyl dendrimers and polymers in solution and immobilised on electrode surfaces

This article reviews the electrochemical properties of different families of redox-active silicon- and amine-based fenocenyl polymers and dendrimers prepared in our laboratory over the last: few years. The electrochemical behaviour of the ferrocenyl polymers both in solution and immobilised oh the electrode depends on the polymer structure. Solution electrochemical studies of Silicon-based ferrocenyl polymers showed that all the redox centres were: electrochemically independent and that polymers containing pendant ferrocenyl moieties undergo oxidative precipitation, yielding polymer films on electrode surfaces. The application of electrodes modified with a ferrocenyl polymer containing octakis(dimethyl-siloxy)-octasilsesquioxane as framework, as mediator in the electrocatalytic oxidation of ascorbic. acid is described. The electrochemical behaviour of silicon- and amine-based dendrimers in which ferrocenyl moieties behave as electronically isolated centres, and also of dendritic macromolecules containing interacting ferrocenyl units has been studied. The feasibility of:modifying electrode Surfaces with these redox-active,metallo-dendrimers containing a controlled number of metal centres has been demonstrated. The application of ferrocenyl dendrimers as electron transfer mediators in amperometric biosensors and in the electrochemical recognition of anions, as well as the use of dendritic terminal ferrocenyl groups for inclusion complexation by cyclodextrins has been outlined. (C) 1999 Elsevier Science S.A. All rights reserved.