Revealing the Dynamic of Excited State Proton Transfer of a pi-Conjugated Salicylidene Compound: An Experimental and Theoretical Study

Autor(es)

Vivas, M. G. ; Germino, J. C. ; Barboza, C. A. ; Simon, Deborah de A. ; Vazquez, P. A. M. ; De Boni, L. ; Atvars, T. D. Z. ; Mendonca, C. R.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 121, n. 2, p. 1283-1290, JAN 19 2017.
• Citações Web of Science: 11

Resumo

Excited state intramolecular proton transfer (ESIPT) in a novel salicylidene sal-3,4-benzophen chromophore is studied by white-light femtosecond pumpprobe 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 (tau(ESIPT) = 150 fs). Subsequently, cooling from the hot cis-keto{*} (hK{*}) to cold cis-keto{*} (cK{*}) state takes place with a characteristic time constant of similar to 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. (AU)

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