Dolidze TD, Khoshtariya DE, Illner P, Kulisiewicz L, Delgado A, van Eldik R (2008)
Publication Type: Journal article
Publication year: 2008
Publisher: American Chemical Society
Book Volume: 112
Pages Range: 3085-3100
Journal Issue: 10
URI: http://www.ncbi.nlm.nih.gov/pubmed/18278899
DOI: 10.1021/Jp077734j
We report the first application of a high-pressure electrochemical strategy to study heterogeneous charge transfer (CT) in a room-temperature ionic liquid, [BMIM][BTA]. High-pressure kinetic studies on electron exchange for two redox couples of different charge type, viz. [Fe(bipy)3]3+/2+ and [Fe(cp)2]+/0, at bare Au electrodes within the range of 0.1 -150 MPa, revealed large positive volumes of activation that were found to be virtually the same for the two redox couples in terms of the CT rate constants and diffusion coefficients, despite the reactant's charge type. Independent viscosity (fluidity) studies at elevated pressure (up to 175 MPa), were also performed and revealed a pressure coefficient closely resembling the former ones. Complementary temperature-dependent kinetic studies within the range of 298-358 K also revealed the virtual similarity in activation enthalpies for the same kinetic and diffusion processes, as well as the viscosity of [BMIM][BTA]. A rigorous analysis of the complete variety of obtained results strongly indicates that dynamic (frictional) control of CT is operative by way of the full adiabatic mechanism. The contribution of the Franck-Condon term to the activation free energy of the kinetic process seems almost diminished because of the high value of electronic coupling and freezing out of the outer-sphere reorganization energy. Further analyses indicate that frictional control most probably takes place through slow translational modes (implying "minimal volume" cooperative dislocations) of constituent ions. This kind of motion seems further slowed down within the vicinity of the active site presumably located within the diffusive-like zone situated next to the compact (first) part of the metal/ionic liquid junction. © 2008 American Chemical Society.
APA:
Dolidze, T.D., Khoshtariya, D.E., Illner, P., Kulisiewicz, L., Delgado, A., & van Eldik, R. (2008). High-pressure testing of heterogeneous charge transfer in a room-temperature ionic liquid: Evidence for solvent dynamic control. Journal of Physical Chemistry B, 112(10), 3085-3100. https://dx.doi.org/10.1021/Jp077734j
MLA:
Dolidze, Tina D., et al. "High-pressure testing of heterogeneous charge transfer in a room-temperature ionic liquid: Evidence for solvent dynamic control." Journal of Physical Chemistry B 112.10 (2008): 3085-3100.
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