Supramolecular assembly of mebendazolium and dihydrogen phosphate ions in a new anthelmintic salt

A new mebendazolium di-hydrogen phosphate phospho-ric acid solid material was obtained and characterized by single-crystal X-ray diffraction and complementary solid-state techniques {systematic name: 5-benzoyl-2-[(meth-oxy-carbon-yl)amino]-1<i>H</i>-1,3-benzo-diazol-3-ium di-hydrogen phosphate-phos-pho-ric acid (1/1), C₁₆H₁₄N₃O₃ ⁺·H₂PO₄ ^-·H₃PO₄}. Structure solution confirmed proton transfer from phospho-ric acid towards the basic imidazole ring of mebendazole. The mebendazolium cation and the di-hydrogen phosphate anion assemble in the solid state in a cyclic hydrogen-bond-driven supra-molecular motif, as observed in all mebendazolium/oxyanions structures reported in the literature. This salt crystallizes in the monoclinic <i>P</i>2₁/<i>c</i> (No. 14) space group. A detailed study of the crystal structure performed by atom-to-atom and global Hirshfeld surface analysis indicates that several hydrogen bonds act as the main inter-molecular inter-actions stabillizing the material. The new material is stable up to 458 K.