Detailed theoretical investigation on ESIPT process of pigment yellow 101

Abstract

Based on density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, the detailed excited state intramolecular proton transfer (ESIPT) mechanism of 2,2 0 -dihydroxy-1,1 0naphthalazine (P.Y. 101) has been investigated theoretically. Unlike previous theoretical investigation of P.Y. 101, our calculated results not only reproduce the absorption and fluorescence spectra reported in the previous experiment, but also were completed with considering solvent effect. It further demonstrates that the TDDFT theory we adopted is very reasonable and effective. The calculations of main bond lengths and bond angles involving in the hydrogen bondings (O 1 -H 2 /N 3 and O 4 -H 5 /N 6 ) as well as the infrared vibrational spectra and as well as the calculated hydrogen bonding energies demonstrated the intramolecular hydrogen bond was strengthened in the S 1 state. In addition, qualitative and quantitative intramolecular charge transfer based on the frontier molecular orbitals provided the possibility of the ESIPT reaction. The potential energy surfaces of ground state and the first excited state have been constructed to illustrate the ESIPT mechanism. Based on our calculations, the equilibrium ESIPT process exists in the S 1 state. And after the radiative transition, reversed GSIPT can also occur in the S 0 state.

A detailed theoretical simulation about the excited state dynamical process for the novel (benzo[d]thiazol‐2‐yl)‐5‐(9H‐carbazol‐9‐yl)phenol molecule

“…It is well known that the modification of the fluorescence molecule via introducing another functional moiety can bring novel changes, which may provide unprecedented opportunities for further harnessing the ESIPT reaction . 2‐(2‐hydroxyphenyl)benzothiazole (HBT) molecule should be one of the most investigated ESIPT systems due to its simple synthesis and relative chemical structures.…”

A theoretical investigation on the excited state intramolecular single or double proton transfer mechanism of a salicyladazine system

“…[7][8][9][10][11][12][13][14] Given their photochemical and photophysical properties, novel chromophores based on the ESIPT feature have been increasingly designed and developed in recent years, such as fluorescent sensors, molecular switches, organic optoelectronic materials, laser dyes, and white light-emitting materials. [15][16][17][18][19][20][21][22][23][24][25] In fact, the ESIPT process occurs via the pre-existing intramolecular hydrogen bond. In the S 0 state, two π-conjugated groups can be connected via a hydrogen bond, and the form could be called the enol form.…”

Exploring the possibilities of double proton transfer in hydrazides: A theoretical approach

“…Tautomerism in hydrazides is characterized by translocation of a proton from a donor (N―H) moiety to an acceptor moiety (C═O) with a pre‐established intramolecular hydrogen bond giving birth to a phototautomer phenomenon, commonly termed as excited state intramolecular proton transfer (ESIPT). Proton transfer is primly induced by the energy difference pertaining to locally excited state and the relaxed excited state, and the gradient spread over a potential energy surface (PES) connecting these two extremities governs the relative kinetics of the system . The keto ground state, a thermodynamically stable entity, upon photoexcitation achieves an excited keto* generally referred to as local excited state.…”