| Popis: |
Oligomers of ethylendioxythiophene-vinylene have been prepared. Their optical, electrochemical and chemical properties have been studied in detail by absorp- tion and emission spectroscopy as well as cyclic voltamme- try, Raman techniques and spectroelectrochemistry comple- mented 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 func- tion generates more robust electronic ground states regard- ing 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 sta- bilising balance effect between the oxygen fragment in the EDO groups (mesomeric effect) and the linear p-conjugated structure. The oxidised species have been characterised, which show the ability for the formation of mixed valence charge-transfer complexes and p dimers of different oxida- tion states, in particular, in the electrochemical medium, re- sulting 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 elec- tronic properties of these new oligomers in the context of the oligomer approach has been proposed. |
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