Photoacidity of the N-salicylidene-5-chloroaminopyridine

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• 作者：Cristina Aparecida Barboza^a ; ¹ ; ^{crissetubal@gmail.com} ; José ; Carlos Germino^a ; ¹ ; Luí ; s Gustavo Teixeira Alves Duarte^a ; ¹ ; Fernando Junior Quites^b ; Pedro Antô ; nio Muniz Vazquez^a ; Teresa Dib Zambon Atvars^a
• 关键词：Salicylidenes ; Photoacidity ; Dipole moment ; TD-DFT ; TCSPC
• 刊名：Journal of Luminescence
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：184
• 期：Complete
• 页码：268-272
• 全文大小：1033 K
• 卷排序：184

文摘

Due to the occurrence of excited intramolecular proton transfer (ESIPT) in salicylidenes, in this article the photoacidity of the N  -salicylidene-5-chloroaminopyridine (sal-5-Cl-py) was evaluated by electronic absorption and fluorescence spectroscopy. The results strongly suggest that sal-5-Cl-py in aqueous solution behaves as a superacid, ΔpKa=ΔpKa=8.83, due to a large change of the dipole moment under electronic excitation between protonated and deprotonated species. Theoretical calculations under the density functional theory – DFT framework showed that as result of the ESIPT the electron density migrates from the phenol to the chloroaminepyridine ring. Such a charge migration is the driving force for the proton transfer reaction.