Abstract

Excited state intramolecular proton transfer (ESIPT) is a vital event of numerous natural photophysical processes being, therefore, crucial in chemistry and molecular biology [1]. Due to the transient character of its ground state, ESIPT has been used in several applications [2,3]. In the ESIPT, electrons are promoted upon photoexcitation to the singlet excited state of the enol form of chromophore. Subsequently, the ultrafast ESIPT occurs and the cis-keto form at the singlet excited state is produced, which is stabilized by the intramolecular hydrogen bond. Since the ESIPT is much faster than the fluorescence process (radiative decay), the emission observed for the ESIPT chromophores is preferentially due to the keto tautomer [4]. All these processes can be mapped by time-resolved transient absorption spectroscopy. In this context, here we report on the ESIPT dynamic of novel salicylidene chromophore (KG21), a compound with potential application in photonic devices. For that, we combined the white-light femtosecond pump-probe technique and the Density Functional Theory. Figure 1 shows the excited state dynamics results for the KG21. Figure 1 (a) shows the colormap representing the time- and wavelength-resolved dynamics of the transient absorption spectrum. The excited state absorption (ESA) spectra for different times are displayed in Fig. 1 (b), while Fig. 1 (c) illustrates a decay curve for probe pulse at the peak of ESA band.

© 2015 IEEE