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(Electro)chemical Oxidation of 6,13‐Bis[tri(isopropyl)silylethynyl]pentacene to its Radical Cation and Dication
Author(s) -
Schundelmeier Simon,
Speiser Bernd,
Bettinger Holger F.,
Einholz Ralf
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201700435
Subject(s) - dication , chemistry , electrochemistry , redox , reaction rate constant , electron transfer , reactivity (psychology) , photochemistry , cyclic voltammetry , pentacene , radical ion , molecule , inorganic chemistry , electrode , kinetics , organic chemistry , ion , medicine , physics , alternative medicine , quantum mechanics , pathology , thin film transistor
6,13‐Bis[tri(isopropyl)silylethynyl]pentacene is a prototypical molecule for organic semiconductor and photovoltaic materials, which makes its electrochemical (redox) properties highly interesting. However, previous cyclic voltammetric studies have provided only limited information. Kinetic and persistence information and identification of the oxidation product(s) and their further reaction or oxidation have not been reported. Thus, an extended electrochemical and spectroscopic investigation of this compound was conducted in CH 2 Cl 2 and THF electrolytes at Pt electrodes. The electrochemically and chemically generated radical cation of the title compound was characterized by using ESR and UV/Vis/NIR spectroscopy and quantum‐chemical modeling. In CH 2 Cl 2 , further oxidation to a dication with chemical reversibility at fast timescales but follow‐up reactivity at slow timescales was observed. Pertinent parameters of the electron transfers (formal potentials E 0 , electron transfer rate constants k s , electron stoichiometry n ) were determined. The diffusion coefficients, D , in the two electrolytes were estimated from electrochemical and pulse gradient spin echo (PGSE) NMR spectroscopy data. Simulations of cyclic voltammograms supported the proposed oxidation mechanism and allowed the estimation of further reaction parameters.