Robust Ethylenedioxythiophene–Vinylene Oligomers from Fragile Thiophene–Vinylene Cores: Synthesis and Optical, Chemical and Electrochemical Properties of Multicharged Shapes

Abstract

Oligomers of ethylendioxythiophene-vinylene have been prepared. Their optical, electrochemical and chemical properties have been studied in detail by absorption and emission spectroscopy as well as cyclic voltammetry, Raman techniques and spectroelectrochemistry complemented with quantum chemical calculations. A comparison with their non-ethylendioxy and non-vinylene parents has been done. The inclusion of the EDO plus the vinylene function generates more robust electronic ground states regarding the largely flexible thiophene-vinylene (n TV) oligomeric homologues. The redox features of the new compounds are also rich of oxidative processes arising as an interesting stabilising balance effect between the oxygen fragment in the EDO groups (mesomeric effect) and the linear π-conjugated structure. The oxidised species have been characterised, which show the ability for the formation of mixed valence charge-transfer complexes and π dimers of different oxidation states, in particular, in the electrochemical medium, resulting that the electrochemical response is accounted for a succession of aggregation and electron-transfer steps. With this work, a full understanding of the optical and electronic properties of these new oligomers in the context of the oligomer approach has been proposed.

Design of Assembled Systems Based on Conjugated Polyphenylene Derivatives and Carbon Nanohorns

“…anchoring octyl chains and poly(benzyl ether) dendrons, leading to the solubilisation of a thiophene chain of eleven units . Other compounds have been described more recently, using the same solubilising strategy to prepare organic materials with application in the field of electronic devices ,. In our case, we decided to synthesise molecules with different numbers of thiophene units (six, nine or twelve for DI‐3 tph, TRI‐3 tph and TETRA‐3 tph, respectively) with a central phenyl core.…”

[All]‐S,S‐dioxide Oligo‐Thienylenevinylenes: Synthesis and Structural/Electronic Shapes from Their Molecular Force Fields

“…This state is non‐allowed by one‐photon absorption selection rules and gets slightly active due to the vibrational mixing. In the new oxidized oligomers, 5 – 7 , an initial red‐shift of the main absorption band is observed on 5 – 7 as 3.123→2.594→2.322 eV (i.e., Δ E =0.801 eV) that is overall smaller than in 1 – 3 ( 3.463→2.844→2.546 eV, i.e., Δ E =0.917 eV), which is, again, the outcome of the already smaller/larger HOMO–LUMO gap/π‐conjugation in the dioxide compounds in comparison to the non‐oxidized homologues . From another perspective, this smaller Δ E in 5 – 7 compared to 1 – 3 reveals the saturation of the π‐electron delocalization in π‐conjugated oligomers, in the case of the dioxides, with the same number of π‐electrons, a larger π‐conjugation is attained [TD‐DFT calculations on these compounds have been carried out to support the experimental results (Figure S3 and Table S1)].…”

Preise 2015 der Real Sociedad Española de Química

“…Marks an der Northwestern University und kehrte anschließend an die UMA zurück, an der sie zur Zeit durch ein Ramón‐y‐Cajal‐Stipendium unterstützt wird. Sie ist Coautorin einer Veröffentlichung in Chemistry—A European Journal über Ethylendioxythiophen‐Vinylen‐Oligomere 7…”