Transport and electron transfer dynamics in a polyether-tailed cobalt bipyridine molten salt: Electrolyte effects

Mary Elizabeth Williams, Leslie J. Lyons, Jeffrey W. Long, Royce W. Murray

Research output: Contribution to journalArticle

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Abstract

Transport, ionic conductivity, and viscosity properties of the metal complex molten salt [Co(bpy(CO 2 MePEG-350) 2 ) 3 ](ClO 4 ) 2 (MePEG = monomethyl-terminated polyether, average MW = 350) are strongly affected by dissolution of LiClO 4 electrolyte in the melt. The physical self-diffusion of the [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+ and the rate of [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange are slowed, the melt viscosity increased and ionic conductivity decreased, and thermal activation barriers for all are enhanced by increasing [LiClO 4 ]. Most of the effects are associated with the Li + cation/polyether coordination well-known in polymer electrolytes, in which chain cross-linking and a decrease in chain segmental mobility occurs. The [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange reaction is shown to be adiabatic (kinetic prefactor ca. 10 13 s -1 ), and modest changes in its rate with [LiClO 4 ] are caused by changes in the electron transfer barrier energy. The results are used to draw a hierarchy of dynamics in the metal complex melt in which, for [LiClO 4 ] = 1.3 M, the average diffusive jump rate is ca. 3 s -1 , the average electron hopping rate is ca. 3 s -1 , and the rate of short-range motions of the hard metal complex core within its soft polyether shell (producing adjacent core - core contacts) is ca. ≥ 10 5 s -1 .

Original languageEnglish (US)
Pages (from-to)7584-7591
Number of pages8
JournalJournal of Physical Chemistry B
Volume101
Issue number38
StatePublished - Sep 18 1997

Fingerprint

molten salt electrolytes
Polyethers
Carbon Monoxide
Cobalt
Electrolytes
Molten materials
Coordination Complexes
electron transfer
cobalt
Metal complexes
Salts
Electrons
Ionic conductivity
ion currents
Viscosity
electrolytes
metals
Energy barriers
viscosity
electrons

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

@article{e527a23446b34c5e920f0e1ba3b347a0,
title = "Transport and electron transfer dynamics in a polyether-tailed cobalt bipyridine molten salt: Electrolyte effects",
abstract = "Transport, ionic conductivity, and viscosity properties of the metal complex molten salt [Co(bpy(CO 2 MePEG-350) 2 ) 3 ](ClO 4 ) 2 (MePEG = monomethyl-terminated polyether, average MW = 350) are strongly affected by dissolution of LiClO 4 electrolyte in the melt. The physical self-diffusion of the [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+ and the rate of [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange are slowed, the melt viscosity increased and ionic conductivity decreased, and thermal activation barriers for all are enhanced by increasing [LiClO 4 ]. Most of the effects are associated with the Li + cation/polyether coordination well-known in polymer electrolytes, in which chain cross-linking and a decrease in chain segmental mobility occurs. The [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange reaction is shown to be adiabatic (kinetic prefactor ca. 10 13 s -1 ), and modest changes in its rate with [LiClO 4 ] are caused by changes in the electron transfer barrier energy. The results are used to draw a hierarchy of dynamics in the metal complex melt in which, for [LiClO 4 ] = 1.3 M, the average diffusive jump rate is ca. 3 s -1 , the average electron hopping rate is ca. 3 s -1 , and the rate of short-range motions of the hard metal complex core within its soft polyether shell (producing adjacent core - core contacts) is ca. ≥ 10 5 s -1 .",
author = "Williams, {Mary Elizabeth} and Lyons, {Leslie J.} and Long, {Jeffrey W.} and Murray, {Royce W.}",
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Transport and electron transfer dynamics in a polyether-tailed cobalt bipyridine molten salt : Electrolyte effects. / Williams, Mary Elizabeth; Lyons, Leslie J.; Long, Jeffrey W.; Murray, Royce W.

In: Journal of Physical Chemistry B, Vol. 101, No. 38, 18.09.1997, p. 7584-7591.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Transport and electron transfer dynamics in a polyether-tailed cobalt bipyridine molten salt

T2 - Electrolyte effects

AU - Williams, Mary Elizabeth

AU - Lyons, Leslie J.

AU - Long, Jeffrey W.

AU - Murray, Royce W.

PY - 1997/9/18

Y1 - 1997/9/18

N2 - Transport, ionic conductivity, and viscosity properties of the metal complex molten salt [Co(bpy(CO 2 MePEG-350) 2 ) 3 ](ClO 4 ) 2 (MePEG = monomethyl-terminated polyether, average MW = 350) are strongly affected by dissolution of LiClO 4 electrolyte in the melt. The physical self-diffusion of the [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+ and the rate of [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange are slowed, the melt viscosity increased and ionic conductivity decreased, and thermal activation barriers for all are enhanced by increasing [LiClO 4 ]. Most of the effects are associated with the Li + cation/polyether coordination well-known in polymer electrolytes, in which chain cross-linking and a decrease in chain segmental mobility occurs. The [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange reaction is shown to be adiabatic (kinetic prefactor ca. 10 13 s -1 ), and modest changes in its rate with [LiClO 4 ] are caused by changes in the electron transfer barrier energy. The results are used to draw a hierarchy of dynamics in the metal complex melt in which, for [LiClO 4 ] = 1.3 M, the average diffusive jump rate is ca. 3 s -1 , the average electron hopping rate is ca. 3 s -1 , and the rate of short-range motions of the hard metal complex core within its soft polyether shell (producing adjacent core - core contacts) is ca. ≥ 10 5 s -1 .

AB - Transport, ionic conductivity, and viscosity properties of the metal complex molten salt [Co(bpy(CO 2 MePEG-350) 2 ) 3 ](ClO 4 ) 2 (MePEG = monomethyl-terminated polyether, average MW = 350) are strongly affected by dissolution of LiClO 4 electrolyte in the melt. The physical self-diffusion of the [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+ and the rate of [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange are slowed, the melt viscosity increased and ionic conductivity decreased, and thermal activation barriers for all are enhanced by increasing [LiClO 4 ]. Most of the effects are associated with the Li + cation/polyether coordination well-known in polymer electrolytes, in which chain cross-linking and a decrease in chain segmental mobility occurs. The [Co(bpy(CO 2 MePEG-350) 2 ) 3 ] 2+/+ electron self-exchange reaction is shown to be adiabatic (kinetic prefactor ca. 10 13 s -1 ), and modest changes in its rate with [LiClO 4 ] are caused by changes in the electron transfer barrier energy. The results are used to draw a hierarchy of dynamics in the metal complex melt in which, for [LiClO 4 ] = 1.3 M, the average diffusive jump rate is ca. 3 s -1 , the average electron hopping rate is ca. 3 s -1 , and the rate of short-range motions of the hard metal complex core within its soft polyether shell (producing adjacent core - core contacts) is ca. ≥ 10 5 s -1 .

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