Adsorption of 1,10-Phenanthroline-2,9-dithiol on Gold and Silicon Surfaces

Abstract

Derivatives of 1,10-phenanthroline are used in bio- and chemosensors as well as in supramolecular chemistry. A reliable method of fixation onto gold, silicon, and other surfaces is necessary to solve some problems in these fields and will provide new application opportunities. In this study, adsorption of a sulfur-containing 1,10-phenanthroline derivative (PhenSH) onto gold and silicon surfaces was examined using atomic force microcsopy, surface plasmon resonance (SPR), and X-ray photoelectron spectroscopy techniques and compared to that of a sulfur-free derivative. We report PhenSH–Au bond formation with most likely orthogonal orientation with respect to the surface. The adsorption process proceeds by forming a layer of molecules that are not firmly bound to the surface which then form a covalent bond. The compound is sterically accessible to reagents in the solution, such as metal ions, which will allow using its coordinating properties to create SPR and surface-enhanced Raman spectroscopy-based chemosensors and to attach phenanthroline-based supramolecular nanostructures to nanoparticles or nanodevices.