Excited state proton transfer in a ‘super’ photoacid based on a phenol–pyridinium biaryl chromophore

Autor:	Fabrice Morlet Savary, Christiane Carre, Xavier Allonas, J.-Pierre Malval, Vincent Diemer, Hélène Chaumeil, Albert Defoin, Patrice Jacques
Rok vydání:	2008
Předmět:	chemistry.chemical_compound Reaction rate constant chemistry Excited state Solvatochromism Substituent General Physics and Astronomy Pyridinium Physical and Theoretical Chemistry Chromophore Conjugated system Photochemistry Fluorescence
Zdroj:	Chemical Physics Letters. 455:238-241
ISSN:	0009-2614
DOI:	10.1016/j.cplett.2008.02.099
Popis:	We report the effect of a N-methylpyridinium substituent on the photoacidity enhancement of a phenol derivative. The steady-state and time-resolved fluorescence of this new phenolic ‘super’ photoacid (HPPy) are measured in different solvents in comparison with its methoxy analogue (MPPy). Solvatochromic shifts and nonradiative rate constants ascribable to excited state proton transfer (ESPT) are correlated with the empirical Kamlet–Taft parameters (π*, α, and β). Whereas, spectral shift of MPPy is mainly correlated to π* parameter, HPPy is also strongly influenced by β. At 77 K, ESPT is hampered and leads to the switch ‘on’ emission of conjugated base.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::859c5cb457e794e367ce021375c68370 https://doi.org/10.1016/j.cplett.2008.02.099 Zobrazit plný text záznamu Full Text from ScienceDirect