Electrochemical Characterization of the Self‐assembled Monolayer of 6‐Thioguanine on the Mercury Electrode

Abstract

A self-assembled monolayer (SAM) of 6-thioguanine (6TG) was formed on the hanging mercury drop electrode, under open circuit potential, from 6TG solutions. The SAM has been characterized by cyclic voltammetry under both in situ and ex situ conditions and the experimental data reveal that the film is a densely packed structure of chemisorbed (mercury-thiol) molecules. The presence of this SAM has no influence on the rate of outer-sphere electrode reactions but strongly inhibits inner-sphere processes. The electrode reaction involving the Fe(CN) 3À=4À 6 couple appears reversible in a hanging mercury drop electrode coated by the 6TG-SAM.

Mercury reduction and complexation by natural organic matter in anoxic environments

“…Thiol compounds and DOM are also reported to have a high affinity to sorb elemental Hg(0) (47)(48)(49)(50). Therefore, direct interaction and stabilization of dissolved Hg(0) by HA cannot be ruled out in our experiment ( Fig.…”

“…Reactions and high affinities of thiols for Hg(0) are well documented (32,(47)(48)(49)(50), although direct bond formation between Hg(0) and thiols (-SH) is unlikely due to both species being electron rich and Hg(0) having no unshared electrons. However, Hg is a class B soft metal with a strong tendency to coordinate or complex with soft bases such as thiols (21,32).…”

Oxidation process induced by 2-mercaptopyrimidine at a mercury electrode

“…This means that the "condensed" monolayer of C 4 H 3 N 2 S-Hg does not inhibit such a reaction. In contrast, the product of a similar reaction involving thiopurines forms full monolayers that block further occurrence of that reaction [14][15][16][17][18]. This different behavior is attributed to the fact that ring-ring stacking interactions between pyrimidine molecules are weaker than those between purines.…”

“…The oxidative and interfacial behavior of thiopurines on the HMDE has recently been studied in detail using a variety of voltammetric techniques [14][15][16][17][18]. A similar investigation in relation with 2MP has not yet been reported.…”

Electrochemical study of S–nitrosoglutathione and nitric oxide by carbon fibre NO sensor and cyclic voltammetry – possible way of monitoring of nitric oxide

“…In the case of GSH, there are evident both reductive (at potential about −0.48 V) and oxidative (about −0.40 V) signals. The thirst signal at −0.48 V corresponds to reduction of GSHg complex, which is formed according to reaction 1 [71,72]:…”