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Cyclic Voltammetry Study of Asymmetrical Trityl Di- and Trisulfides on Coated and Bare Gold Electrodes

2008; American Chemical Society; Volume: 112; Issue: 17 Linguagem: Inglês

10.1021/jp712138c

1932-7455

Nathir A. F. Al‐Rawashdeh, Imad A. Abu‐Yousef, Sofian M. Kanan,

Electrochemical Analysis and Applications

The electrochemical reduction processes of a new series of asymmetrical trityl di- (TrSSR) and trisulfides (TrSSSR) were studied using cyclic voltammetry on 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. This study shows that the electron-transfer mechanism of the studied compounds causes the cleavage of the S−S σ bond on the bare gold electrode and cleavage of the Tr−S σ bond on the coated gold electrode. The electrochemical electron-transfer process for both systems strongly depends on the structure and the type of substituents that are electron donors or acceptors. The experimental approach allows estimating the values of Eored and the intrinsic barrier for the formation of the radical anions.