Theoretical Insights into the Intermolecular Hydrogen Bond Effect on ESIHT Process in 2′-Hydroxychalcone: A Combined DFT/TDDFT Study

Abstract

Present computational study lighting up the ground and excited states properties of 2′-hydroxychalcone (2′-HC) and 2′-HC + (H2O)2-[2′-HCH] molecules by employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Furthermore, micro-solvation, hydrogen bond dynamics and natural charge analysis studies have been done for both molecules at ground/excited states by using effective fragment potential (EFP1)/natural bond orbital (NBO) methods at 6-31G(d,p)/B3LYP level. The excited state intra-molecular hydrogen atom transfer (ESIHT) mechanism of 2′-HC was investigated via potential energy scans (PES). No hydrogen atom transfer is observed in the S3 state of 2′-HC and S1/S3 states of 2′-HCH. The optimized molecular structures, molecular orbital’s and electrostatic potential maps were depicted along with UV-Vis absorption spectra. Good consistency between experimental and computational absorption wavelength for a 2′-HC molecule with methanol as solvent.