Imae, Ichiro; Tada, Naofumi; Harima, Yutaka published an article in 2021. The article was titled 《Tuning of electronic properties of novel donor-acceptor polymers containing oligothiophenes with electron-withdrawing ester groups》, and you may find the article in Polymer Bulletin (Heidelberg, Germany).Name: 2,5-Dibromothiophene The information in the text is summarized as follows:
To investigate the substituent effects introduced into oligothiophene units, a series of novel donor-acceptor conjugated polymers containing ester-substituted oligothiophenes were synthesized by the direct C-H arylation polycondensation of bis(ester-substituted thienyl)benzothiadiazole and dibromo-substituted oligothiophenes. The UV-visible absorption spectra of three polymers showed two absorption bands in the visible light wavelength region, ascribed to π-π* transition and the intramol. charge transfer bands. The oxidation potentials of the polymers exhibited a neg. shift with an increase in the chain length of the oligothiophene units. By comparing these polymers with alkyl-substituted analogs, it was found that the introduction of electron-withdrawing ester groups induced a neg. shift in the HOMO (HOMO) and the LUMO (LUMO) energy levels and affected the LUMO rather than the HOMO energy levels. As a preliminary experiment, organic photovoltaic cells using these polymers were prepared, and their photoelec. conversion characteristics were investigated in relation to their chem. structures. In the part of experimental materials, we found many familiar compounds, such as 2,5-Dibromothiophene(cas: 3141-27-3Name: 2,5-Dibromothiophene)
2,5-Dibromothiophene(cas: 3141-27-3) , is mainly used as pharmaceutical intermediate and synthesis intermediate. 2,5-Dibromothiophene may be used as starting reagent for the synthesis of α,α′-didecylquater-, -quinque- and -sexi-thiophenes.Name: 2,5-Dibromothiophene
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary