5,12-TIPS-Substitution of Tetracene: Effects on Redox Potentials and Cyclic Voltammetric Behavior in CH₂Cl₂ and THF

Tetracene and 5,12-bis(tri(isopropyl)silylethynyl)tetracene (TIPS-tetracene) are widely used in optoelectronic applications. Their electrochemical behavior is compared in the present work by cyclic voltammetry and ESR-spectroelectrochemistry. Their electrode reaction mechanisms and relevant physico-chemical parameters are derived for ${\mathrm{CH}}_2$ ${\mathrm{Cl}}_2$ - and THF-based electrolytes from experimental data. DFT calculations provide energies of the acenes and their radical ions in gas phase and solution environments. The differences between the behavior of the compounds and between the solvent conditions are discussed. The effect of the two TIPS substituents on the formal potentials of the (first) one-electron oxidation and reduction steps in the two solvents and on the kinetic stabilization of the radical ions is evaluated. As a global redox characteristic, an "electrochemical gap" is discussed for the tetracenes under the solvent conditions.