Solvation Effect of Li⁺ on the Voltammetric Properties of [PMo₁₂O₄₀]³⁻. Part 2: Comparative Studies on the Preferential Solvation in Acetonitrile+S and Acetone+S Mixtures

Abstract

, the presence of Li produced a two-electron wave at nearly the same potential as the first oneelectron wave in acetonitrile or acetone. The voltammetric behavior of [PMo 12 O 40 ] 3À in a binary mixture of acetonitrile and solvent S was compared with those in a mixture of acetone and S. When the donor number (DN) of S > 20, the first two-electron wave was converted into one-electron waves in such binary mixtures. The conversion occurred at lower mole fractions of S in an acetonitrile S mixture than in an acetone S mixture. The 7 Li NMR results showed that the preferential solvating ability of Li with S was greater in the former mixture. A linear relationship was found between the iso-solvation point x iso (S) and the reciprocal of the difference between the DNs of S and acetonitrile, which gave the basis to explain the anomalies observed for a mixture of acetonitrile and H 2 O.

Electrochemistry of Polyoxometalates: From Fundamental Aspects to Applications

“…The effects of Li + and Na + on the voltammetric behavior of Keggin‐type POMs were investigated in various solvents with the help of 7 Li NMR, leading to the selective solvation of Li + in binary solvents. The Li‐coupled reduction processes of PMo 12 O 40 ] 3‐ was investigated in acetone to obtain protonation constants and Li association constants (Scheme S6) –…”

Preparation of tetrabutylammonium salt of a mono-Ru(iii)-substituted α-Keggin-type silicotungstate with a 4,4′-bipyridine ligand and its electrochemical behaviour in organic solvents

“…It is well known that the redox potential of POMs depends on negative charges of POMs, the type of counter cations and the pH of the solution. [17][18][19][20][21][22][23] It is also known that the redox potentials of POMs are affected by anion solvation. 18,19,[24][25][26] Keita and Nadjo's group reported that the first one-electron reduction potentials of [SiW 12 O 40 ] 4−/5− and [P 2 W 18 O 62 ] 6−/7− were shifted to more positive potentials with increases in the Gutmann acceptor number 27 of the solvent.…”

“…Small cations, such as H + , Li + and Na + , were more strongly associated with the reduced forms of POMs than with the corresponding oxidised forms and caused changes in the redox potentials and/or number of transferred electrons. [20][21][22][23]31,32 Himeno's group reported that the solvation ability to small cations increased with an increase in the Lewis basicity (≈donor number) of solvents and that the solvation of cations caused weakening of the interaction between the small cations and POMs. 21,22 Thus, the redox potential changes for POM anions are rationalized in terms of the electron donor-acceptor concept of the solvent.…”

Study on Preferential Solvation of Water by Electrochemical Method

“…However, the effect of water always is ubiquitous but often overlooked as a background environment in the water and organic solvent. In fact, the preferential solvation of water plays an important role in electrochemical behavior of solute , hydrogen evolution reaction , double layer capacitance , the process of electronic transfer . Exploring preferential solvation of water by electrochemical methods would provide new insights into the effect of water in the field of electrochemical research.…”