Solvent effect on the hammett reaction constant for the electroreduction of substituted benzophenones

Abstract

Solvent effects on the Hammett ρ value for the cathodic reduction of substituted benzophenones were determined. The electrochemistry of a series of 11 compounds was studied in acetonitrile, acetone, dimethyl sulphoxide, propylene carbonate, N,N‐dimethylformamide, N,N‐dimethylacetamide, N,N‐diethylformamide and hexamethylphosphoric triamide. The ρ values for the reversible one‐electron transfer are described by the Lewis acid‐base model ρ = − 0.006AN + 0.003DN + 0.391, where AN = solvent acceptor number and DN = solvent donor number.

Trade-Offs in Capacity and Rechargeability in Nonaqueous Li–O2 Batteries: Solution-Driven Growth versus Nucleophilic Stability

“…[27][28][29][30][31] The location of the half-wave potential is determined by the solvents' ability to solvate the ions. For the cation Li + , the half-wave potential has been found to be well correlated with the DN of the solvent.…”

Application of clean technologies using electrochemistry in ionic liquids

“…6 for [Bmpy] where the ρ value of 0.32 is observed, while a value of 0.31 was obtained for [Bmim]. These values are typical for polar solvents such as acetonitrile 22…”

“…Also, the electrochemical reduction potentials ( E p ) are very sensitive to the electronic nature of substituents,21, 22 as described by the Hammett substituent constants (σ, given in Table 1), which, in turn, are very sensitive to the polarity of the medium via the well know Hammett relation; where E p, x is the reduction potential of benzophenone and E p, s is the reduction potentials of substituted benzopheneones. Significantly, the slope ρ is dependent on the polarity of the medium (e.g.…”

“…Significantly, the slope ρ is dependent on the polarity of the medium (e.g. ρ = 0.33 for acetonitrile22). As such, simple electrochemical experiments using these probe molecules can reveal significant information about the protic (or otherwise) nature of RTILs and also their overall effective polarity.…”

The influence of aluminium cations on electrocarboxylation processes in undivided cells with Al sacrificial anodes

“…The compounds show in cyclic voltammetry one reversible peak couple followed by an irreversible peak at more negative potentials [28][29][30][31][32][33]. The ketyl radical anions derived from aryl alkyl ketones are not very stable; they undergo a radical-radical coupling reaction to give pinacols [28][29][30][31].…”