Structure and electrochemical reactivity of 3-[tris(2-methoxyethoxy)silyl]-propanethiol adsorbed on silver surface

A novel stable self-assembled chemisorbed layers, providing protection of metal surface against electrooxidation capable of blocking propylene carbonate (PC) electroreduction and Li electrodeposition, were produced from 3-[tris-(2-methoxyethoxy)silyl]-propanethiol (SIS2) on silver. Reflection-absorption infrared spectroscopy (RAIRS) indicated cleavage of the S-H bond upon adsorption of SIS1 [3-(trimethoxysilyl)-propanethiol] and SIS2 species with the formation of S-Ag bonds on the metal surface. By cyclic voltammetry it was found that the primary adsorbate formed on a Ag electrode at E_ad (between − 0.2 and − 1.2 V vs. SCE) underwent reductive desorption at E < − 1.3 V vs. SCE. From the charge involved in this process, the saturation surface coverage was estimated as 4.2 10^− 10 mol cm^− 2. A compact SIS2 layer after long-time aging (hydrolysis and condensation) was electroinactive and thus non-desorbable from the electrode surface during the potential cycling. The structures of SIS2 and its complexes with Li⁺ cations on the Ag surface were calculated and visualized by the AM1d semi-empirical method.