Electrochemistry and Spectroelectrochemistry of Polynuclear Rhenium (III) Chloride Cluster Complexes and Their One-Electron-Reduction Products in a Basic Room-Temperature Chloroaluminate Molten Salt

Sandra K.D. Strubinger, I-Wen Sun, Walter E. Cleland, Charles L. Hussey

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32 Citations (Scopus)

Abstract

The dimeric, metal-metal-bonded rhenium(III) complex [Re2Cl8]2− is stable in the basic aluminum chloride-1-methyl-3-ethyl-imidazolium chloride (AlCl3-MeEtimCl) molten salt and can be reduced to [Re2Cl8]3− at a glassy-carbon electrode in a reversible electrode reaction with a voltammetric half-wave potential, E1/2, of ca. −0.58 V in the 49.0/51.0 mol % melt versus the A13+/Al couple in the 66.7/33.3 mol % melt at 40°C. It is possible to electrochemically generate stable, bulk solutions containing [Re2Cl8]3−, provided that oxygen is rigorously excluded from the electrochemical cell. The average Stokes-Einstein products for [Re2Cl8]2− and [Re2Cl8] are 2.0 × 10−10 and 1.2 × 10−10 g cm s−2 K−1, respectively. The addition of Re3Cl9 to basic AlCl3–MeEtimCl produces the trimeric, metal-metal-bonded rhenium(III) complex [Re3Cl12]3−. This species can also be reduced at a glassy-carbon electrode in a one-electron, reversible electrode reaction with an E1/2 of about −0.34 V in this same basic melt. However, E1/2 for this reaction is dependent upon the pCl of the melt, indicating the loss of chloride ion from the coordination sphere of the cluster during reduction to form a species of the type [Re3Cl12_x](4−x)− for which x may be 1. It is possible to electrochemically generate stable solutions of this reduced species in the absence of oxygen. The average Stokes-Einstein products for [Re3Cl12]3− and its one-electron-reduction product are 1.3 × 10−10 and 1.0 × 10−10 g cm s−2 K−1, respectively. Both [Re2Cl8]2− and [Re3Cl12]3− exhibit an additional multielectron voltammetric reduction process at potentials negative of their one-electron reduction waves. In both cases, bulk electrolysis experiments conducted at potentials negative of these very large waves destroyed the parent clusters. In basic melt at temperatures of ca. 175° C or more, each [Re3Cl12]3− ion is irreversibly converted to one [Re2Cl8]2− ion. Absorption spectroscopic data for [Re2Cl8]2−, [Re3C12]3−, and their one-electron-reduction products are reported.

Original languageEnglish
Pages (from-to)993-999
Number of pages7
JournalInorganic Chemistry
Volume29
Issue number5
DOIs
Publication statusPublished - 1990 Jan 1

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Spectroelectrochemistry
Rhenium
molten salts
rhenium
Electrochemistry
electrochemistry
Molten materials
Chlorides
Salts
chlorides
Metals
Electrons
room temperature
products
Electrodes
electrodes
glassy carbon
Glassy carbon
Ions
electrons

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

@article{454a03180b7d46bf8bf83982e895acda,
title = "Electrochemistry and Spectroelectrochemistry of Polynuclear Rhenium (III) Chloride Cluster Complexes and Their One-Electron-Reduction Products in a Basic Room-Temperature Chloroaluminate Molten Salt",
abstract = "The dimeric, metal-metal-bonded rhenium(III) complex [Re2Cl8]2− is stable in the basic aluminum chloride-1-methyl-3-ethyl-imidazolium chloride (AlCl3-MeEtimCl) molten salt and can be reduced to [Re2Cl8]3− at a glassy-carbon electrode in a reversible electrode reaction with a voltammetric half-wave potential, E1/2, of ca. −0.58 V in the 49.0/51.0 mol {\%} melt versus the A13+/Al couple in the 66.7/33.3 mol {\%} melt at 40°C. It is possible to electrochemically generate stable, bulk solutions containing [Re2Cl8]3−, provided that oxygen is rigorously excluded from the electrochemical cell. The average Stokes-Einstein products for [Re2Cl8]2− and [Re2Cl8] are 2.0 × 10−10 and 1.2 × 10−10 g cm s−2 K−1, respectively. The addition of Re3Cl9 to basic AlCl3–MeEtimCl produces the trimeric, metal-metal-bonded rhenium(III) complex [Re3Cl12]3−. This species can also be reduced at a glassy-carbon electrode in a one-electron, reversible electrode reaction with an E1/2 of about −0.34 V in this same basic melt. However, E1/2 for this reaction is dependent upon the pCl of the melt, indicating the loss of chloride ion from the coordination sphere of the cluster during reduction to form a species of the type [Re3Cl12_x](4−x)− for which x may be 1. It is possible to electrochemically generate stable solutions of this reduced species in the absence of oxygen. The average Stokes-Einstein products for [Re3Cl12]3− and its one-electron-reduction product are 1.3 × 10−10 and 1.0 × 10−10 g cm s−2 K−1, respectively. Both [Re2Cl8]2− and [Re3Cl12]3− exhibit an additional multielectron voltammetric reduction process at potentials negative of their one-electron reduction waves. In both cases, bulk electrolysis experiments conducted at potentials negative of these very large waves destroyed the parent clusters. In basic melt at temperatures of ca. 175° C or more, each [Re3Cl12]3− ion is irreversibly converted to one [Re2Cl8]2− ion. Absorption spectroscopic data for [Re2Cl8]2−, [Re3C12]3−, and their one-electron-reduction products are reported.",
author = "Strubinger, {Sandra K.D.} and I-Wen Sun and Cleland, {Walter E.} and Hussey, {Charles L.}",
year = "1990",
month = "1",
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doi = "10.1021/ic00330a019",
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journal = "Inorganic Chemistry",
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Electrochemistry and Spectroelectrochemistry of Polynuclear Rhenium (III) Chloride Cluster Complexes and Their One-Electron-Reduction Products in a Basic Room-Temperature Chloroaluminate Molten Salt. / Strubinger, Sandra K.D.; Sun, I-Wen; Cleland, Walter E.; Hussey, Charles L.

In: Inorganic Chemistry, Vol. 29, No. 5, 01.01.1990, p. 993-999.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Electrochemistry and Spectroelectrochemistry of Polynuclear Rhenium (III) Chloride Cluster Complexes and Their One-Electron-Reduction Products in a Basic Room-Temperature Chloroaluminate Molten Salt

AU - Strubinger, Sandra K.D.

AU - Sun, I-Wen

AU - Cleland, Walter E.

AU - Hussey, Charles L.

PY - 1990/1/1

Y1 - 1990/1/1

N2 - The dimeric, metal-metal-bonded rhenium(III) complex [Re2Cl8]2− is stable in the basic aluminum chloride-1-methyl-3-ethyl-imidazolium chloride (AlCl3-MeEtimCl) molten salt and can be reduced to [Re2Cl8]3− at a glassy-carbon electrode in a reversible electrode reaction with a voltammetric half-wave potential, E1/2, of ca. −0.58 V in the 49.0/51.0 mol % melt versus the A13+/Al couple in the 66.7/33.3 mol % melt at 40°C. It is possible to electrochemically generate stable, bulk solutions containing [Re2Cl8]3−, provided that oxygen is rigorously excluded from the electrochemical cell. The average Stokes-Einstein products for [Re2Cl8]2− and [Re2Cl8] are 2.0 × 10−10 and 1.2 × 10−10 g cm s−2 K−1, respectively. The addition of Re3Cl9 to basic AlCl3–MeEtimCl produces the trimeric, metal-metal-bonded rhenium(III) complex [Re3Cl12]3−. This species can also be reduced at a glassy-carbon electrode in a one-electron, reversible electrode reaction with an E1/2 of about −0.34 V in this same basic melt. However, E1/2 for this reaction is dependent upon the pCl of the melt, indicating the loss of chloride ion from the coordination sphere of the cluster during reduction to form a species of the type [Re3Cl12_x](4−x)− for which x may be 1. It is possible to electrochemically generate stable solutions of this reduced species in the absence of oxygen. The average Stokes-Einstein products for [Re3Cl12]3− and its one-electron-reduction product are 1.3 × 10−10 and 1.0 × 10−10 g cm s−2 K−1, respectively. Both [Re2Cl8]2− and [Re3Cl12]3− exhibit an additional multielectron voltammetric reduction process at potentials negative of their one-electron reduction waves. In both cases, bulk electrolysis experiments conducted at potentials negative of these very large waves destroyed the parent clusters. In basic melt at temperatures of ca. 175° C or more, each [Re3Cl12]3− ion is irreversibly converted to one [Re2Cl8]2− ion. Absorption spectroscopic data for [Re2Cl8]2−, [Re3C12]3−, and their one-electron-reduction products are reported.

AB - The dimeric, metal-metal-bonded rhenium(III) complex [Re2Cl8]2− is stable in the basic aluminum chloride-1-methyl-3-ethyl-imidazolium chloride (AlCl3-MeEtimCl) molten salt and can be reduced to [Re2Cl8]3− at a glassy-carbon electrode in a reversible electrode reaction with a voltammetric half-wave potential, E1/2, of ca. −0.58 V in the 49.0/51.0 mol % melt versus the A13+/Al couple in the 66.7/33.3 mol % melt at 40°C. It is possible to electrochemically generate stable, bulk solutions containing [Re2Cl8]3−, provided that oxygen is rigorously excluded from the electrochemical cell. The average Stokes-Einstein products for [Re2Cl8]2− and [Re2Cl8] are 2.0 × 10−10 and 1.2 × 10−10 g cm s−2 K−1, respectively. The addition of Re3Cl9 to basic AlCl3–MeEtimCl produces the trimeric, metal-metal-bonded rhenium(III) complex [Re3Cl12]3−. This species can also be reduced at a glassy-carbon electrode in a one-electron, reversible electrode reaction with an E1/2 of about −0.34 V in this same basic melt. However, E1/2 for this reaction is dependent upon the pCl of the melt, indicating the loss of chloride ion from the coordination sphere of the cluster during reduction to form a species of the type [Re3Cl12_x](4−x)− for which x may be 1. It is possible to electrochemically generate stable solutions of this reduced species in the absence of oxygen. The average Stokes-Einstein products for [Re3Cl12]3− and its one-electron-reduction product are 1.3 × 10−10 and 1.0 × 10−10 g cm s−2 K−1, respectively. Both [Re2Cl8]2− and [Re3Cl12]3− exhibit an additional multielectron voltammetric reduction process at potentials negative of their one-electron reduction waves. In both cases, bulk electrolysis experiments conducted at potentials negative of these very large waves destroyed the parent clusters. In basic melt at temperatures of ca. 175° C or more, each [Re3Cl12]3− ion is irreversibly converted to one [Re2Cl8]2− ion. Absorption spectroscopic data for [Re2Cl8]2−, [Re3C12]3−, and their one-electron-reduction products are reported.

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