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Benzothiadiazole vs. iso-Benzothiadiazole: Synthesis, Electrochemical and Optical Properties of D–A–D Conjugated Molecules Based on Them

Benzothiadiazole vs. iso-Benzothiadiazole: Synthesis, Electrochemical and Optical Properties of D–A–D Conjugated Molecules Based on Them

Authors :
Natalia V. Obruchnikova
Oleg A. Rakitin
Ekaterina A. Knyazeva
Nikita S. Gudim
Ivan S. Golovanov
L. V. Mikhal’chenko
Vadim V. Popov
Source :
Molecules, Volume 26, Issue 16, Molecules, Vol 26, Iss 4931, p 4931 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

This paper presents an improved synthesis of 4,7-dibromobenzo[d][1,2,3]thiadiazole from commercially available reagents. According to quantum-mechanical calculations, benzo[d][1,2,3]thiadiazole (isoBTD) has higher values of ELUMO and energy band gap (Eg), which indicates high electron conductivity, occurring due to the high stability of the molecule in the excited state. We studied the cross-coupling reactions of this dibromide and found that the highest yields of π-spacer–acceptor–π-spacer type compounds were obtained by means of the Stille reaction. Therefore, 6 new structures of this type have been synthesized. A detailed study of the optical and electrochemical properties of the obtained π-spacer–acceptor–π-spacer type compounds in comparison with isomeric structures based on benzo[c][1,2,5]thiadiazole (BTD) showed a red shift of absorption maxima with lower absorptive and luminescent capacity. However, the addition of the 2,2′-bithiophene fragment as a π-spacer resulted in an unexpected increase of the extinction coefficient in the UV/vis spectra along with a blue shift of both absorption maxima for the isoBTD-based compound as compared to the BTD-based compound. Thus, a thorough selection of components in the designing of appropriate compounds with benzo[d][1,2,3]thiadiazole as an internal acceptor can lead to promising photovoltaic materials.

Details

ISSN :
14203049
Volume :
26
Database :
OpenAIRE
Journal :
Molecules
Accession number :
edsair.doi.dedup.....9a439439af93522b1235b5c625eb7bb6
Full Text :
https://doi.org/10.3390/molecules26164931