Electrochemical Studies of Chlorine Containing Silanes

Abstract

The reduction potentials of a series of mono-, di- and trichloro alkyl and aryl substituted silanes was investigated by cyclic voltammetry. It was shown that chlorosilanes can be reduced in two one electron steps at potentials more positive than -1V vs SCE. The solvent type (THF, MeCN), silane type and polymerization and electrolyte concentration were varied and found to greatly impact the reduction potential.

General Concepts and Recent Advances in the Electrochemical Transformation of Chloro‐ and Hydrosilanes

“…Mechanistic conclusions based on CV studies without synthetic evidence should therefore be treated with caution, since standing alone they leave much room for interpretation. [107] One trend by which the verisimilitude to the discussion of chlorosilane reduction can be estimated is the decreasing reduction potential of oligo-and polychlorosilanes with increasing SiÀ Si chain length. [41,61] Reduction of chlorosilanes in the low cathodic range should accordingly allow readily accessible reduction to silicon deposition, which is not the case in practice.…”

“…Since no standard electrolytes and electrode materials have yet been established for CV studies of hydro‐ and halosilanes, it is futile to compare reduction potentials of halosilanes in different environments, as shown by Jouikov [24] . In the past, [39,50,67,103,104–106] as well as in more recent studies, [43,61,107] reduction potentials of halosilanes are therefore found in a wide potential window, especially the frequently investigated Me 3 SiCl (Table 2, entries 1–6). However, within an identical electrolyte and electrode system, clear trends can be identified for the reduction potential of halosilanes:…”

“…In addition, a reversible signal often occurs in the low cathodic range, which can be caused by traces of moisture and accompanying HCl formation, [36,39–41] or by the presence of oxygen, [24,63] if not carefully dried and prepared, at best in a glovebox. Mechanistic conclusions based on CV studies without synthetic evidence should therefore be treated with caution, since standing alone they leave much room for interpretation [107] . One trend by which the verisimilitude to the discussion of chlorosilane reduction can be estimated is the decreasing reduction potential of oligo‐ and polychlorosilanes with increasing Si−Si chain length [41,61] .…”