Molecular structure elucidation, charge transfer interactions, electronic properties, vibrational spectral investigation and molecular docking of the antiviral active molecule (E)-4-[1-(2-carbamothioylhydrazinylidene)ethyl]-phenyl benzoate dimer - aided by density functional theory

Abstract

The molecular structure of the novel thiosemicarbazide (E)-4-[1-(2-carbamothioylhydrazinylidene) ethyl] - phenyl benzoate has been synthesized and subjected to Raman and Fourier transform infrared spectral studies. Optimized parameters of (E)-4-[1-(2-carbamothioylhydrazinylidene) ethyl] - phenyl benzoate monomer and dimer have been compared with X-ray diffraction data. The existence of hydrogen bonded intramolecular interactions, intermolecular interactions and the hyperconjugative energy leading to the stabilization of the system have been revealed by natural bond orbital analysis. Charge transfer interactions from highest occupied molecular orbital to lowest unoccupied molecular orbital and the observed low energy gap predict the molecule to be more reactive. Molecular electrostatic potential image shows the potential binding site is around the sulfur atom. The spectra have been analyzed and the assignments of the normal modes of vibrations have been carried out with the help of normal coordinate analysis following the scaled quantum chemical force field methodology. The observed spectral shift substantiates the spectral evidence of the intermolecular hydrogen bonding. Molecular docking scores reveal good binding affinity and the inhibition activity of the molecule against dengue viral protein 4c11.