Photophysical Approach of Biological Active Benzofuran Derivatized Pyrrole with Green Synthesized Silver NPs Using C. Roseus Leaves: Computational and Spectroscopic Study

Abstract

The electronic absorption and fluorescence emission spectra of N-(2,5-dimethyl-pyrrol-1-yl)-2-(5-methoxybenzofuran-3-yl)acetamide (DPMA) molecule were recorded in various solvents at room temperature with the aim of estimation of ground state (\({\mu }_{g}\)) and excited states (\({\mu }_{e}\)) dipole moments using Lippert’s, Bakshiev’s and Kawski-Chamma-Viallete’s equations. The results were signified that, the excited state dipole moment is greater than the ground state dipole moment, which indicates the excited state dipole moment is more polar than the ground state dipole moment. Ecofriendly green synthesis of silver nanoparticles (Ag NPs) were synthesized using catharanthus roseus (C.R) leaf extract was done. These synthesized Ag NPs were used as fluorescence quenchers. Fluorescence lifetime measurement is carried out using time correlated single photon counting technique of DPMA molecule with various concentrations of Ag NPs. A linear Stern-Volmer (S-V) plot was obtained in steady state and transient state method. Furthermore we have estimated computational calculations such as ground state optimized geometry, molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), experimental and theoretical energy band gap, solvent polarity and normalized solvent polarity values. Morphology and sizes of green synthesized silver NPs were characterized by transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDX) and also characterized by UV-Visible absorption.