SERS spectra, AIM, and MD investigations of a bioactive acetamide, an AChE and BChE inhibitor derivative

The adsorption behavior of 2-(4-oxo-2-thioxothiazolidin-3-yl)-N-(p-tolyl)acetamide (OTA) on silver nanoparticles was studied using surface enhanced Raman scattering (SERS) and density functional theory (DFT). The presence of various inactive Raman modes in SERS is due to polarizability variations in the presence of metal. Negative adsorption energy shows strong bonding between silver and OTA. Structural characteristics represent charge transfer of the metal cluster that underwent bonding with OTA. The hardness and chemical potential of OTA are 1.6527 and −4.4407 eV, while these in OTA1 (C=O near to Ag6) are 1.1789 and −3.7449 eV, and the reduction in these values shows a strong shared interaction with OTA and Ag. The υC=O are observed in SERS at all concentrations and show up and down changes in frequencies, giving interaction with Ag and orientation changes with concentration changes. Since OTA is an acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitor, docking with 1GQR and 6ASM gives binding affinities of −8.5 and −7.8 kcal mol−1. Molecular dynamics (MD) simulations indicate that docked OTA remained stable, maintained by H-bonds. When OTA was near Ag6, changes were observed in electron density at several places.