Impact of crystal and molecular structure of three novel thiosulfonate crystals on their vibrational and NMR parameters

Abstract

Due to antimicrobial potential of S-containing compounds, the current study explores experimentally the crystal and molecular structure of three new thiosulfonates at 100 K, notably S-ethyl 4-aminobenzene-1-sulfonothioate (1), S-ethyl 4-acetamidobenzene-1-sulfonothioate (2), and S-methyl 4-acetamidobenzene-1-sulfonothioate (3). Theoretical analysis between their molecular structure and vibrational IR, Raman, as well as NMR parameters is given. The details of -SO2-S- structural motif are analyzed theoretically using HOOH, HS-SH and H3CS-SCH3, as model molecules. The experimental structural parameters, as determined by low temperature X-ray diffraction method are accurately predicted using DFT-B3LYP combined with large and flexible aug-cc-pVTZ basis set. In case of C-S-S-C dihedral angle the crystal forces are responsible for larger difference with respect to isolated molecules, predicted in the gas phase. In addition, electronic properties of the title compounds are explored using theoretical calculations of their geometric and magnetic aromaticity indexes and substituent push-pull effect. The obtained results provide a deeper insight into their molecular structure and IR/Raman and NMR spectroscopic properties. Finally, these compounds could be directly used in future in vitro investigation of therapeutic potential of the studied and structurally similar compounds.