First signals of electrochemically oxidized species of TTF and TTM-TTF: A study by in situ spectroelectrochemical FTIR and DFT calculations

Abstract

A first study by in situ FTIR spectroelectrochemistry of TTF and TTM-TTF has been undertaken. The oxidation, in this case, is caused only by electrochemistry, which constitutes a clear advantage over chemical oxidation since no side products are present in the solution. In this context, we obtained the signals of neutral, radical cation, and dication species of TTF and TTM-TTF. The experimental conditions were chosen in order to avoid the possible formation of p-dimer species and to obtain a satisfactory signal-to-noise ratio. A weak signal was detected for TTF and a stronger one for TTM-TTF. The changes induced by the oxidation process in the IR spectra of TTF and TTM-TTF have been analyzed with the aid of B3P86/6-31G** density functional theory (DFT) calculations, which allows for a comprehensive assignment of the bands observed. DFT calculations show that the IR signal associated to the asymmetric stretching of the lateral C=C bonds can be used as a structural signature to identify the different oxidation states of TTF and TTM-TTF. The frequency downshift and the intensity increase undergone by the n asym (C=C) vibration upon oxidation are shown to be the key factors to understand the evolution of the IR spectra.

A Fully Conjugated TTF–π–TCAQ System: Synthesis, Structure, and Electronic Properties

“…In the resulting conformation, the dithiole rings are nearly perpendicular to the anthracene plane and the SMe groups lie in the plane of the dithiole rings. This disposition of the SMe groups was already reported for the TTM‐TTF dication 23. 24 The net atomic charges calculated for 11 2+ by using the natural population analysis (NPA) algorithm indicate that the electrons have been mainly removed from the SMe‐dithiole rings, which accumulate a charge of +0.91 e each, whereas the anthracene unit remains mainly neutral (+0.05 e).…”

Design of novel tetra-hetero[8]circulenes: a theoretical study of electronic structure and charge transport characteristics

“…This method was demonstrated to provide reliable geometries and charge transport properties of the organic semiconductors in many previous studies. [53][54][55][56][57][58] The chemical structures of all compounds are shown in Fig. 1, whereas their shapes are given in the ESI le.…”

In situ FTIR spectroelectrochemistry and spectral simulations using DFT: Efficient complementary tools to elucidate complex electrochemical mechanisms

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