Electrode Kinetics Associated with Tetracyanoquinodimethane (TCNQ), TCNQ•-, and TCNQ2- Redox Chemistry in Acetonitrile As Determined by Analysis of Higher Harmonic Components Derived from Fourier Transformed Large Amplitude ac Voltammetry

The dc and first to eighth harmonic components derived from Fourier transformed large amplitude ac voltammetry have been used to determine the heterogeneous electron transfer kinetics (k(0)) of electron transfer processes involving reduction of 7,7,8,8-tetracyanoquinodimethane (TCNQ), oxidation and reduction of TCNQ(center dot-), and oxidation of TCNQ(2-) in acetonitrile. This protocol permits removal of a possible contribution from the cross redox reaction between TCNQ and TCNQ(2-). k(0) values were determined by comparison of the experimental data with simulations that take into account the effect of uncompensated resistance and double layer capacitance. Values of 0.30 +/- 0.05 cm s(-1) were obtained at platinum and glassy carbon electrodes for both TCNQ(0/center dot-) and TCNQ(center dot-/2-) processes when studies were undertaken over a range of concentrations using both reduction and oxidation perspectives. Difficulties associated with measurement of electrode kinetics near the reversible limit and comparisons with literature data are considered.