Excited-state intramolecular proton transfer (ESIPT) in 2-(2′-hydroxyphenyl)-oxazole and -thiazole

Autor:	Robert G. Brown, Wolfgang Rettig, Vladimir Kharlanov, Denis LeGourriérec
Rok vydání:	2000
Předmět:	Chemistry General Chemical Engineering General Physics and Astronomy General Chemistry Photochemistry Tautomer chemistry.chemical_compound Ab initio quantum chemistry methods Excited state Triplet state Ground state Thiazole Conformational isomerism Oxazole
Zdroj:	Journal of Photochemistry and Photobiology A: Chemistry. 130:101-111
ISSN:	1010-6030
DOI:	10.1016/s1010-6030(99)00206-3
Popis:	The azoles 2-(2 0 -hydroxyphenyl)oxazole (HPO) and 2-(2 0 -hydroxyphenyl)-4-methylthiazole (HPT) have been synthesised and studied in order to compare their photophysical characteristics. Their absorption and emission properties are reported in non-polar, alcoholic and aqueous media. Ground and excited state pK data were determined by spectroscopy and a model is proposed to explain the behaviour of HPT and HPO as a function of the pH. Excitation spectra and quantum chemical calculations suggest an equilibrium of ground state conformers. The calculations also predict a small energy barrier for rotation in the first excited singlet state for the proton transferred tautomers. The resulting twisted structure of the tautomer form possesses a biradicaloid nature, and is near-degenerate in energy with the first excited triplet state. ©2000 Elsevier Science S.A. All rights reserved.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ca0fb86cd5da01ce4b01f0f6c44fadae https://doi.org/10.1016/s1010-6030(99)00206-3 Zobrazit plný text záznamu Full Text from ScienceDirect