Synthesis, characterization and crystal structure of a new organic salt of antidiabetic drug metformin resulting from a proton transfer reaction

• Published in: Journal of molecular structure 2019-10, Vol.1193, p.310-314
• Main Authors: Ghasemi, Fatemeh, Rezvani, Ali Reza, Ghasemi, Khaled, Abdul Razak, Ibrahim, Rosli, Mohd Mustaqim
• Format: Article
• Language: English
• Subjects: Metformin; Proton transfer; Pyridine-2,6-bis(monothiocarboxylic) acid; X-ray structure
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2019.05.040

The new organic salt of antidiabetic drug metformin, [HMet][pdtcH] (1), where pdtcH = pyridine-2,6-bis(monothiocarboxylic) acid and Met = metformin, was synthesized and characterized by FTIR, UV–Vis, 1H and 13C NMR spectroscopy. Solid-state structure of [HMet][pdtcH] (monoclinic, P21/n) was determined from low-temperature X-ray diffraction data collected at 100K. In this compound, the metformin is monoprotonated. In the crystal packing, the molecules are linked dominantly via intermolecular C–H⋯O, C–H⋯N, C–H⋯S, N–H⋯O and N–H⋯S hydrogen bond interactions, forming a three-dimensional anion-cation network and hence the stabilization of the crystal structure. [Display omitted] •A novel salt of antidiabetic drug metformin resulting from a proton transfer reaction.•Characterization by IR, NMR, UV–Vis spectroscopy and single crystal X-ray crystallography.•Stabilization of the crystal structure as a result of the intermolecular hydrogen bonding.