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Analysis of the Voltammetric Response of Electroactive Guests in the Presence of Non‐Electroactive Hosts at Moderate Concentrations
Author(s) -
Mendoza Sandra,
Castaño Eduardo,
Meas Yunny,
Godínez Luis A.,
Kaifer Angel E.
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200302978
Subject(s) - molecule , ionic strength , chemistry , electrochemistry , electrolyte , cyclic voltammetry , redox , ionic bonding , supporting electrolyte , chemical physics , displacement (psychology) , voltammetry , solubility , aqueous solution , thermodynamics , computational chemistry , inorganic chemistry , electrode , ion , organic chemistry , physics , psychology , psychotherapist
In this work, we present a method to analyze the voltammetric response of reversible redox systems involving molecules that, bearing m non‐interactive electroactive sites, can undergo fast complexation equilibria with host molecules present at concentrations of the same order of magnitude as those of the electroactive guest. The approach focuses on systems for which the relative values of the binding constants for the oxidized and reduced forms of the guest result in the displacement of the voltammetric response of the electroactive molecule as the concentration of the host is increased in the electrolytic solution. This behavior is commonly known as “one wave shift behavior”. Based on a series of assumptions, the method allows calculation of all the thermodynamic parameters that describe the electrochemical and complexation equilibria of a given host‐guest system. The main strength of the suggested method, however, relies on the fact that it only requires cyclic voltammetry data and that it can be used for systems in which large concentrations of the host can not be employed either due to important changes of the ionic strength or to solubility problems. Although the accuracy of the obtained information is limited by the quality of the data provided by the technique, and by the assumptions employed, it certainly represents an excellent starting point for subsequent refinement either using digital simulations or an independent experimental technique.