Synthesis and photophysical properties of pyridyl- and quinolinyl-substituted bis(arylthienyl)pyridines

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2022-05, Vol.427, p.113805, Article 113805
• Main Authors: Moshkina, Tatyana N., Nosova, Emiliya V., Kopotilova, Alexandra E., Savchuk, Maria I., Nikonov, Igor L., Kopchuk, Dmitry S., Khalymbadzha, Igor A., Slepukhin, Pavel A., Ganebnykh, Ilya N., Charushin, Valery N.
• Format: Article
• Language: English
• Subjects: Chromophores; Cross-coupling; Cyclopenta[c]pyridines; DFT calculation; Fluorescence; Sensors for metal cations
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2022.113805

[Display omitted] •Unique bis(arylthienyl)derivatives of 2,2′-bipyridines were designed.•Diethylamino derivatives demonstrated blue shifts upon the treatment with TFA.•Solutions of diphenylamino-substituted chromophores turned yellow in the presence of Cu2+.•The replacement of pyridyl residue with quinolyl leads to decrease in the value of energetic gap. Two series of V-shaped 6,7-dihydro-5H-cyclopenta[c]pyridine chromophores bearing two 5-arylthiophen-2-yl fragments as well as pyridyl or quinolinyl residue have been designed and synthesized. The basic photophysical properties of the compounds have been investigated both in solutions and the solid state. 3,4-Bis(5-(4-diethylaminophenyl)thiophen-2-yl)-1-(quinolin-2-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine 2a demonstrated positive emission solvatochromism, and the collected data were analyzed by using Lippert-Mataga equation, as well as Kosower and Dimroth/Reichardt scales. The ability to detect metal cations has been analyzed for the obtained heterocycles. It is found that addition of 1.5 eq of Cu2+ to diphenylamino-substituted chromophore 1b lead to totally luminescence quenching and solution of chromophore 1b turns dark yellow that can be seen with the naked eye. Additionally, halochromic properties have been examined, it was shown that diethylamino derivatives 1a and 2a demonstrated blue shifts in both absorption and emission spectra upon the treatment with TFA. Also, we checked emission behavior of chromophore 1a in MeCN–water mixtures with different water volume fractions. Finally, DFT calculations have been performed and according data, the replacement of pyridyl residue with quinolinyl one in studied heterocyclic ensembles leads to decrease in the value of energetic gap.