Imad Ali Abu-Yousef
American University of Sharjah, UAE
Title: Synthesis and cyclic voltammetry study of asymmetrical triphenylmethane di- and trisulfides on coated and bare gold electrodes
Biography
Biography: Imad Ali Abu-Yousef
Abstract
A new series of asymmetrical trityl di- (TrSSR) and trisulfides (TrSSSR) were prepared and characterized using 1H-, 13C-NMR and elemental analysis as well as by X-ray crystallography. The materials were tested for their electrochemical reduction processes using cyclic voltammetry on both bare and coated gold electrodes. On a coated gold electrode surface adsorption phenomena are absent; the electrochemical reduction process is irreversible and found to be diffusion controlled. In contrast, on a bare gold electrode surface, a self-assembled monolayer of TrSAuads and RSAuads for disulfides and TrSSAuads or RSSAuads for trisulfides originates after S-S bond breakage observed by simply dipping the gold electrode in a solution of sulfides. The data presented herein indicate that the electrochemical electron transfer process for both systems highly depends on the structure and the type of substituents where the electron transfer process causes the decomposition of the S-S bond on the bare gold electrode and the Tr-S σ bond on the coated gold electrode. The experimental approach allows estimating the values of Eored and the intrinsic barrier for the formation of the radical anions. The results were then compared with those obtained previously on a glassy carbon surface. The structures of the tested compounds are illustrated in the figure below.