ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence

ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence Научная публикация

Журнал

Molecules
ISSN: 1420-3049

Вых. Данные

Год: 2023, Том: 28, Номер: 4, Номер статьи : 1793, Страниц : 20 DOI: 10.3390/molecules28041793

Ключевые слова

imidazole; 2-hydroxyphenyl group; hydrogen bond; ESIPT; luminescence

Авторы

Shekhovtsov Nikita A. ¹ , Nikolaenkova Elena B. ² , Ryadun Alexey A. ¹ , Samsonenko Denis G. ¹ , Tikhonov Alexsei Ya. ² , Bushuev Mark B. ¹

Организации

1	Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
2	N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia

Информация о финансировании (2)

1	Российский научный фонд	21-13-00216
2	Министерство науки и высшего образования Российской Федерации

1H-Imidazole derivatives establish one of the iconic classes of ESIPT-capable compounds (ESIPT = excited state intramolecular proton transfer). This work presents the synthesis of 1-hydroxy-4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LOH,OH) as the first example of ESIPT-capable imidazole derivatives wherein the imidazole moiety simultaneously acts as a proton acceptor and a proton donor. The reaction of LOH,OH with chloroacetone leads to the selective reduction of the imidazolic OH group (whereas the phenolic OH group remains unaffected) and to the isolation of 4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LH,OH), a monohydroxy congener of LOH,OH. Both LOH,OH and LH,OH demonstrate luminescence in the solid state. The number of OH···N proton transfer sites in these compounds (one for LH,OH and two for LOH,OH) strongly affects the luminescence mechanism and color of the emission: LH,OH emits in the light green region, whereas LOH,OH luminesces in the orange region. According to joint experimental and theoretical studies, the main emission pathway of both compounds is associated with T1 → S0 phosphorescence and not related to ESIPT. At the same time, LOH,OH also exhibits S1 → S0 fluorescence associated with ESIPT with one proton transferred from the hydroxyimidazole moiety to the pyridine moiety, which is not possible for LH,OH due to the absence of the hydroxy group in the imidazole moiety.

Shekhovtsov N.A. , Nikolaenkova E.B. , Ryadun A.A. , Samsonenko D.G. , Tikhonov A.Y. , Bushuev M.B.
ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence
Molecules. 2023. V.28. N4. 1793 :1-20. DOI: 10.3390/molecules28041793 WOS Scopus OpenAlex

Поступила в редакцию:	27 янв. 2023 г.
Принята к публикации:	9 февр. 2023 г.
Опубликована в печати:	14 февр. 2023 г.
Опубликована online:	14 февр. 2023 г.

Web of science:	WOS:000941752000001
Scopus:	2-s2.0-85149052918
OpenAlex:	W4320729624

БД	Цитирований
OpenAlex	10
Web of science	11
Scopus	8