Synthesis and Study of Symmetric Olefin-Bridged Bidentate Adsorbates and their Monolayers on Gold

This project describes the synthesis of a series of symmetric olefin-bridged dithiols and their use in the generation of self-assembled monolayers (SAMs) on gold. The olefin-bridged bidentate adsorbates were designed to possess systematically increasing alkyl chain lengths, C-13 and C-14. SAMs from the adsorbates were generated at room temperature in a variety of solvents and at varying concentrations in efforts to create thin films with dense packing and good conformational order. To investigate the influence of the olefin bridge on the overall physical and chemical properties of the films, the resulting SAMs were analyzed using ellipsometry, X-ray photoelectron spectroscopy, polarization-modulation IR reflection-adsorption spectroscopy, and contact angle goniometry, which provided information on film thickness, chemical composition as well as packing density, structural order, and wettability, respectively. For comparison, the olefin-bridged dithiol SAMs were evaluated with respect to those generated from analogous disulfides and monothiol adsorbates.