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|Document Type: ||Article|
|Title: ||The electrochemistry of the ferri/ferrocyanide couple at a calix
resorcinarenetetrathiol-modified gold electrode as a study of novel electrode
modifying coatings for use within electro-analytical sensors|
|Authors: ||Collyer, Stuart D.|
Stirling, Charles J. M.
Higson, Seamus P. J.
|Issue Date: ||2003|
|Citation: ||Stuart D. Collyer, Frank Davis, Andrew Lucke, Charles J. M. Stirling and Séamus P. J. Higson, The electrochemistry of the ferri/ferrocyanide couple at a calixresorcinarenetetrathiol-modified gold electrode as a study of novel electrode modifying coatings for use within electro-analytical sensors, Journal of Electroanalytical Chemistry, Volume 549, 5 June 2003, Pages 119-127|
|Abstract: ||The electrochemistry of the ferri/ferrocyanide redox couple has been studied at
Au electrodes modified with calixresorcinarenetetrathiol. Cyclic voltammetry
in Fe(CN)63- solutions yields three separate pairs of faradaic peaks. Evidence
is given for these redox couples corresponding to the reduction of Fe(CN)63- and
the subsequent re-oxidation of Fe(CN)64- in three differing steric arrangements.
One pair of peaks suggest that when the Fe(CN)63- ion resides within the calix
resorcinarene bowl, electron transport is facilitated by the calix
resorcinarene acting as a charge transfer mediator; in this arrangement the
activation energy is found to be lowered by ~24kJmol-1. Another pair of peaks is
thought to correspond to the reduction of Fe(CN)63- as it approaches the Au
electrode by packing itself in-between adjacent calixresorcinarene molecules.
The third pair of redox peaks is attributed to the reduction and subsequent re-
oxidation of Fe(CN)63-/Fe(CN)64- when the ion resides above a saturated calix
resorcinarene coating; in this case the activation energy was raised by
~45kJmol-1. FTIR spectroscopy of calixresorcinarene-coated Au electrodes and
calixresorcinarene-coated Au electrodes exposed to Fe(CN)63- lends further
support to this argument, by demonstrating that the Fe(CN)63- ion resides within
at least two and possibly three differing environments. Calixresorcinarene
modified electrodes previously exposed to ferricyanide lose the calix
resorcinarene coating together with a surface layer of gold when subsequently
scanned in a phosphate buffer. It therefore appears that the calix
resorcinarene/Fe(CN)63- association is stronger than the Au binding to the
underlying glass material.|
|Appears in Collections:||Staff publications - Cranfield University at Silsoe|
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