Substituted 2-(2-hydroxyphenyl)-3H-quinazolin-4-ones and their difluoroboron complexes: Synthesis and photophysical properties

Tatyana N Moshkina; Emiliya V Nosova; Galina N Lipunova; Marina S Valova; Elizaveta F Petrusevich; Robert Zaleśny; Borys Ośmiałowski; Valery N Charushin

doi:10.1016/j.saa.2021.119497

Substituted 2-(2-hydroxyphenyl)-3H-quinazolin-4-ones and their difluoroboron complexes: Synthesis and photophysical properties

Spectrochim Acta A Mol Biomol Spectrosc. 2021 May 5:252:119497. doi: 10.1016/j.saa.2021.119497. Epub 2021 Jan 21.

Authors

Tatyana N Moshkina¹, Emiliya V Nosova², Galina N Lipunova³, Marina S Valova³, Elizaveta F Petrusevich⁴, Robert Zaleśny⁴, Borys Ośmiałowski⁵, Valery N Charushin⁶

Affiliations

¹ Department of Organic and Biomolecular Chemistry, Ural Federal University, 19 Mira st., Ekaterinburg 620002, Russia.
² Department of Organic and Biomolecular Chemistry, Ural Federal University, 19 Mira st., Ekaterinburg 620002, Russia; Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya st. /20 Akademicheskaya st., Ekaterinburg 620137, Russia. Electronic address: emilia.nosova@yandex.ru.
³ Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya st. /20 Akademicheskaya st., Ekaterinburg 620137, Russia.
⁴ Department of Physical and Quantum Chemistry, Wroclaw University of Science and Technology, 27 Wyb. Wyspiańskiego, Wrocław PL-50370, Poland.
⁵ Department of Organic Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Torun, 7 Gagarin Street, Torun 87-100, Poland.
⁶ Department of Organic and Biomolecular Chemistry, Ural Federal University, 19 Mira st., Ekaterinburg 620002, Russia; Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya st. /20 Akademicheskaya st., Ekaterinburg 620137, Russia.

PMID: 33556794
DOI: 10.1016/j.saa.2021.119497

Abstract

2-(2-Hydroxyphenyl)-3H-quinazolin-4-ones with diverse substituents at phenol ring and their six-membered difluoroboron complexes have been synthesized via few-stage approach. The photophysical properties of target compounds have been investigated in two solvents as well as in the solid state. The nature of substituents and substitution point in the phenol moiety of ligands and resulting BF₂-complexes on the photophysical properties of dyes have been explored. The complex bearing two t-Bu groups proved to be the most emissive in solid state, whereas its 5-methoxy and 4-diethylamino counterparts possess strong emission in toluene solution. The dyes exhibited large Stokes shifts which was attributed to excited state intramolecular proton transfer (ESIPT). Additionally, fluorescence of quinazolinones in the mixture of THF/water was studied. All ligands demonstrated emission enhancement with increase of water fraction which was due to aggregation induced emission.

Keywords: 2-(2-Hydroxyphenyl)–3H-quinazolin-4-ones; BF(2)-complex; ESIPT; Fluorescence; N,O-ligand.