Crystal structure and characterization of the sulfamethazine–piperidine salt

Sulfamethazine [N1‐(4,6‐dimethylpyrimidin‐2‐yl)sulfanilamide] is an antimicrobial drug that possesses functional groups capable of acting as hydrogen‐bond donors and acceptors, which make it a suitable supramolecular building block for the formation of cocrystals and salts. We report here the crystal structure and solid‐state characterization of the 1:1 salt piperidinium sulfamethazinate (PPD+·SUL−, C5H12N+·C12H13N4O2S−) (I). The salt was obtained by the solvent‐assisted grinding method and was characterized by IR spectroscopy, powder X‐ray diffraction, solid‐state 13C NMR spectroscopy and thermal analysis [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)]. Salt I crystallized in the monoclinic space group P21/n and showed a 1:1 stoichiometry revealing proton transfer from SUL to PPD to form salt I. The PPD+ and SUL− ions are connected by N—H+…O and N—H+…N interactions. The self‐assembly of SUL− anions displays the amine–sulfa C(8) motif. The supramolecular architecture of salt I revealed the formation of interconnected supramolecular sheets. The piperidinium–sulfamethazinate salt was prepared by the solvent‐assisted grinding method. The ions are connected by N—H+…O and N—H+…N interactions. The self‐assembly of sulfamethazinate anions displays the amine–sulfa C(8) motif. The supramolecular architecture of the salt revealed the formation of interconnected supramolecular sheets.