Abstract
Computations within Density Functional Theory (DFT) and its Time-Dependent (TD) extension at the B3LYP/6-31G(d) level are performed for both S0 and S1 states to obtain the optimum molecular geometry of the keto-enol photochromic material of the title molecule and to explain the photo-induced ESIPT to generate the corresponding enol tautomer. The choice of the compound is interesting, and deserves attention due to geometrical changes in the electronic structure of the NN linkage during the proton transfer (PT) reaction coordinate.
In particular, PT path is followed by relaxed scan technique for computing potential energy surface (PES) to identify the transition state and to obtain barrier heights in S0 and S1 states. The photoresponsive H-transfer tautomerism is discussed in terms of different computational parameters including enthalpies and free energies. Both electronic reactivity as well as the thermodynamic stability plays together to facilitate proton transfer in the excited- and ground states of the tautomeric forms.
•Explore ESIPT by modelling at B3LYP/6-31G(d) level for both S0 and S1 states of keto-enol photochromic material.•It is helpful in the design of proton transfer materials.•PES profile for PT in the S0 and S1 states explains the ESIPT.•Provide information about NN linkage weakening/strengthening during ESIPT.
