tailieunhanh - A TD-DFT/DFT study on the ESIPT and photophysical properties of symmetrical 2-hydroxybenzilidene1,3-diamines derivatives

The geometries and relative stabilities of 15 tautomeric forms and the corresponding isomers of the studied molecules have been identified and their relative stabilities are investigated. The potential energy profiles and intrinsic reaction coordinates (IRC) calculations along the proton transfer coordinates both in the ground and in the excited state are monitored as well. The impact of the donating (OMe) and withdrawing (NO2) groups on the single and double proton transfers are investigated both in the gas phase and solution. | Cite this paper Vietnam J. Chem. 2023 61 5 612-620 Research article DOI A TD-DFT DFT study on the ESIPT and photophysical properties of symmetrical 2-hydroxybenzilidene1 3-diamines derivatives Shaaban A. Elroby1 Osman I. Osman1 Abdesslem Jedidi1 Walid I. Hassan1 Saadullah G. Aziz1 Rifaat Hilal2 1 Chemistry Department Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia 2 Chemistry Department Faculty of Science University of Cairo Egypt Submitted March 7 2023 Revised May 15 2023 Accepted June 5 2023 Abstract Density functional theory DFT and Time dependent density functional theory TD-DFT methods are used to simulate the photoexcitation and emission of the symmetrical 2-hydroxybenzilidene1 3-diamine HBDA Schiff base and some of its derivatives in the gas phase and solution. Our aim here is to explore the details of Excited-State Intramolecular Proton Transfer ESIPT which underlies the activity of HBDA molecules as fluorescent probes. The structures of HBDA in S0 and the S1 states are optimized utilizing the DFT and TD-DFT methods respectively. Geometric configurations electronic spectra frontier molecular orbitals and potential energy surfaces have all been computed and analyzed for the purpose of interpreting the mechanism of ESIPT. The geometries and relative stabilities of 15 tautomeric forms and the corresponding isomers of the studied molecules have been identified and their relative stabilities are investigated. The potential energy profiles and intrinsic reaction coordinates IRC calculations along the proton transfer coordinates both in the ground and in the excited state are monitored as well. The impact of the donating OMe and withdrawing NO2 groups on the single and double proton transfers are investigated both in the gas phase and solution. Keywords. Hydrogen bond molecular switches proton transfer excited state intramolecular proton transfer ESIPT Schiff bases DFT TD-DFT. 1. INTRODUCTION one another have been .