Electrochemical studies of a new, low-band gap inherently chiral ethylenedioxythiophene-based oligothiophene

In the present paper, the synthesis and characterization of 2,2'-bis{bi[2,2'-(3,4-ethylenedioxy)thiophen-5- yl]}-3,3'-bithianaphthene, nicknamed BT2E4, is reported. We show that electrooligomerization of BT2E4 leads to electroactive films which are evaluated by cyclic voltammetry (CV), UV/vis spectroelectrochemistry and CV coupled with in-situ conductance measurements. Direct comparisons to the properties of the oligomers obtained from the atropisomeric all-thiophene analogue BT2T4 show that the introduction of EDOT leads to a strong reduction of the band-gap, an overall red-shifted absorption spectrum and a rigidification of the structure. Finally, DFT and TD-DFT calculations were performed in parallel to investigate and to compare the electronic and molecular structures of neutral and charged monomer and oligomer species. (C) 2018 Elsevier Ltd. All rights reserved.