Crystal structures of cocrystals of 2,7-dihydroxy-naphthalene with isoniazid and piracetam

Cocrystals of 2,7-dihydroxynaphthalene (DHN, or naphthalene-2,7-diol) with isoniazid (pyridine-4-carbohydrazide) (INH), denoted DHN-INH [C10H8O2 center dot-C6H7N3O, (I)], and piracetam [2-(2-oxopyrrolidin-1-yl)acetamide] (PIR), denoted DHN-PIR [C10H8O2 center dot C6H10N2O2, (II)], were obtained by the solvent-assisted grinding method and characterized by IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Cocrystal (I) crystallized in the triclinic space group P (1) over bar and showed a 2:2 stoichiometry. DHN and INH molecules are connected by O-H center dot center dot center dot N(pyridine) and O-H center dot center dot center dot N(hydrazide) hydrogen bonds. Cocrystal (II) crystallized in the space group Pca2(1) with a 1:1 stoichiometry. DHN and PIR molecules are connected by O-H center dot center dot center dot O=C hydrogen bonds. The supramolecular architecture of cocrystal (I) showed interlinked supramolecular tapes; meanwhile, in cocrystal (II), interlinked supramolecular sheets were observed.