Concentration and solvent dependent SERS, DFT, MD simulations and molecular docking studies of a thioxothiazolidine derivative with antimicrobial properties

Spectroscopic analysis, DFT studies and surface enhanced Raman scattering of antimicrobial bioactive (Z)-2-[5-(5-bromo-2-hydroxybenzylidene)-4-oxo-2-thioxothiazolidin-3-yl]acetic acid (BPTA) have been studied on different silver sols. Very large changes are observed for Raman and SERS bands. Observed variations in the ring modes may be due to surface π-electron interactions and presence of this indicated that molecule is inclined with respect to the metal surface. Changes in orientation are seen in SERS spectra depending on concentration. The molecular docking results show that binding affinity and interactions with the receptors may be supporting evidence for further studies in design further BPTA pharmaceutical applications. Reactivity properties are obtained from DFT and MD simulations. The quantum-mechanical level of theory has been applied to obtain information about the MEP and ALIE surfaces. These calculations give sensitivity of BPTA towards autoxidation mechanism. An influence of water has been studied computationally, via the MD simulations and RDF analysis. This level of theory was also used to identify possible excipient substance for this molecule.