Electronic properties and reactivity of short-chain oligomers of 3,4-phenylenedioxythiophene (PheDOT).
The dimer and trimer of 3,4-phenylenedioxythiophene (PheDOT) have been synthesized. Unlike the parent systems based on 3,4-ethylenedioxythiophene (EDOT), these compounds are quite stable under atmospheric conditions. The electronic absorption spectra of di- and tri-PheDOT exhibit a well-resolved vibronic fine structure indicative of self-rigidification of the conjugated structure by noncovalent intramolecular sulfur-oxygen interactions. Comparison of UV-visible data for the PheDOT oligomers with those of the corresponding EDOT oligomers reveals a faster decrease of the HOMO-LUMO gap with chain length for the former. Cyclic voltammetric data show that whereas PheDOT oxidizes at a lower potential than EDOT, the PheDOT dimer and trimer exhibit much higher oxidation potentials than their EDOT-based analogues. A comparative analysis of the electropolymerization of the three PheDOT-based systems shows that although PheDOT is very difficult to polymerize, its dimer and trimer can be readily electropolymerized. This unexpected increase of reactivity with chain extension is discussed with the aid of theoretical calculations.
Perepichka
Igor F
IF
Groupe Systèmes Conjugués Linéaires, CIMMA, UMR 6200 CNRS, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers, France. i.f.perepichka@durham.ac.uk
Roquet
Sophie
S
Leriche
Philippe
P
Raimundo
Jean-Manuel
JM
Frère
Pierre
P
Roncali
Jean
J