Solvatochromic, DFT Insight into Chemical and Physical Parameters of 4-(4-Nitro-phenoxymethyl)-benzo[h]chromen-2-one (NM2BC).

Abstract

The absorption and fluorescence characteristics of coumarin derivative 4-(4-Nitro-phenoxymethyl)-benzo[h]chromen-2-one (NM2BC) are studied at room temperature in pure organic solvents to understand the nature of its electronic transitions and solvent interactions. The study aims to investigate the solvent-dependent photophysical behavior of NM2BC and estimate the electric dipole moments in both the ground and excited states using solvatochromic methods. Additionally, the work seeks to explore the intramolecular charge transfer (ICT) nature in the excited state and assess the chemical reactivity and stability of NM2BC. The effects of solvents on spectral characteristics were examined using solvatochromic techniques, and Density Functional Theory (DFT) at the CAM-B3LYP/6-311 + + G (d, p) level was utilized in conjunction with quantum chemistry calculations and the solvatochromic shift to estimate electric dipole moments in both the ground and excited states. The electronic structure was analyzed using Frontier Molecular Orbital (FMO) analysis. To evaluate reactivity and stability, Global Reactivity Descriptors were calculated using FMOs. To determine the preferred electrophilic and nucleophilic attack sites, Molecular Electrostatic Potential (MEP) analysis was performed. Strong interactions and intramolecular charge delocalization were investigated using Natural Bond Orbital (NBO) analysis.