Publication 810

Dalton Trans., 45, 19053-19061, 2016 DOI:10.1039/C6DT03870K
Self-assembled monolayer formation of a (N5)Fe(II) complex on gold electrodes: electrochemical properties and coordination chemistry on a surface

Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Université Paris Saclay, CNRS, Orsay Cedex, France
Laboratoire d'Electrochimie Moléculaire, UMR CNRS 7591, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris Cedex 13, France

A coordinatively unsaturated FeII complex bearing a pentadentate ligand (N,N′,N′-tris(2-pyridyl-methyl)-1,2-diaminoethane) functionalized with a cyclic disulfide group has been prepared in order to graft reactive metal entities as self-assembled monolayers (SAMs) on gold electrodes. Prior to grafting, exogenous ligand exchange has been investigated by cyclic voltammetry (CV) in solution, showing that the nature of the first coordination sphere (N5)FeII–X (X = Cl−, OTf−, MeCN, acetone) can be tuned, thanks to the control of the chemical conditions. The FeII complex has been immobilized on gold electrodes by spontaneous (passive) adsorption as well as by an electro-assisted method. The resulting SAMs were characterised by XPS and AFM analyses. CV experiments implementing these SAMs as working electrodes showed that the first coordination sphere of the grafted FeII complex can be controlled by adjusting the chemical conditions, similarly to the studies in a homogeneous solution. Finally, the supported FeII complex proved to be reactive with superoxide generated at the electrode surface by reduction of dissolved dioxygen. Under the employed conditions, leaking of the metal complex was not observed.