Revealing the Dynamic of Excited State Proton Transfer of a π-Conjugated Salicylidene Compound: An Experimental and Theoretical Study
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- 作者：M. G. VivasJ. C. Germino ; C. A. Barboza ; Deborah de A. Simoni ; P. A. M. Vazquez ; L. De Boni ; T. D. Z. Atvars ; C. R. Mendonça
- 刊名：Journal of Physical Chemistry C
- 出版年：2017
- 出版时间：January 19, 2017
- 年：2017
- 卷：121
- 期：2
- 页码：1283-1290
- 全文大小：519K
- ISSN：1932-7455
文摘
Excited state intramolecular proton transfer (ESIPT) in a novel salicylidene sal-3,4-benzophen chromophore is studied by white-light femtosecond pump–probe and time-resolved fluorescence techniques, as well as by theoretical calculations under the time dependent density functional theory framework. We show that when the sal-3,4-benzophen chromophore (in enol form) is excited (at 390 nm) to the cis-enol* form, it is quickly converted to the hot cis-keto* (hK*) form due to the fast ESIPT process (τESIPT = 150 fs). Subsequently, cooling from the hot cis-keto* (hK*) to cold cis-keto* (cK*) state takes place with a characteristic time constant of ∼600 fs, with following relaxation decay time of 37 ps related with the photodynamic from sal-3,4-benzophen due to the occurrence of the cis → trans photoisomerization and intersystem crossing mechanisms. Finally, we observed the fluorescence emission from the cis-keto* at 575 nm. The dynamics of the optical process was modeled using rate equations with the proper energy level diagram and supported by theoretical calculations.