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

Authors :
Gudim, Nikita S.
Knyazeva, Ekaterina A.
Mikhalchenko, Ludmila V.
Golovanov, Ivan S.
Popov, Vadim V.
Obruchnikova, Natalia V.
Rakitin, Oleg A.
Source :
Molecules; Aug2021, Vol. 26 Issue 16, p4931-4931, 1p
Publication Year :
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 E<subscript>LUMO</subscript> and energy band gap (E<subscript>g</subscript>), 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
14203049
Volume :
26
Issue :
16
Database :
Complementary Index
Journal :
Molecules
Publication Type :
Academic Journal
Accession number :
152148229
Full Text :
https://doi.org/10.3390/molecules26164931