Electrochemical Deposition of a Luminescent Alkoxysilyl-Based Fluorenone Film Exhibiting Halide Sensitivity

The luminescent alkoxysilyl-functionalized fluorenone (N-(9-N-fluorenimine)-N'-(triethoxysilanepropyl) urea) has been synthesized to chelate specifically halide ions via hydrogen bonding of the fluorenimine moiety. Based on the propensity of siloxanes to form electrodeposited films, we examined the electrochemical behavior of this alkoxysilyl functionalized fluorenone on gold electrode in THF-based electrolyte. In the presence of water traces, quartz crystal microbalance coupled with cyclic voltammetry underlines the electrocatalyzed surface-condensation of the molecule occurring on the electrode surface in cathodic reduction. Scanning electrochemical microscopy allows to perform localized electrodeposition in the feedback mode. Epitaxially and PVD-grown polycrystalline gold surfaces were used for topography observations by STM and spectroscopic characterizations of the resulting coating. Finally, spectrofluorometry was carried out specifically for sensing halide ions chelated by the alkoxysilyl fluorenone-based mono-layer electrodeposited on the electrode surface. (C) 2016 The Electrochemical Society.