Crystal Structure of Five Solid Forms from Isonicotinamide and Carboxylic Acids Assembled by Classical Hydrogen Bonds and Other Noncovalent Interactions

Abstract Cocrystallization of the commonly available isonicotinamide, with a series of carboxylic acids gave a total of five new anhydrous and hydrous multicomponent solid forms: (isonicotinamide)2: (suberic acid) [(L)2 • (H2sub), H2sub = suberic acid] (1), (isonicotinamide)2: (α-ketoglutaric acid): H2O [(HL+)2 • (kga2−) • H2O, kga2− = α-ketoglutarate] (2), (isonicotinamide): (1,2-phenylenediacetic acid) [(L) • (H2pda), H2pda = 1,2-phenylenediacetic acid] (3), (isonicotinamide): (4-nitrophthalic acid) [(HL+) • (Hnpta−), Hnpta− = 4-nitrohydrogenphthalate] (4) and (isonicotinamide)4: (butane-1,2,3,4-tetracarboxylic acid) [(L)4 • (H4bta), H4bta = butane-1,2,3,4-tetracarboxylic acid] (5). The five solid forms have been characterised by XRD, IR and EA and their melting points were also reported. Their structural and supramolecular aspects are fully analyzed. The result shows that 2 and 4 are organic salts with only the aryl N in L protonated, 1, 3 and 5 are co-crystals. The crystal packing is interpreted by the strong N-H•••O, O-H•••N and O-H•••O hydrogen bonds. The carboxamide dimers were existed in all solid forms by a pair of N-H•••O hydrogen bonds. Further inspection of the crystal packing told that a different set of additional CH-O/CH2-O, CH-N, O-C, O-O, O-N, O-π and π-π associations contribute to the stabilization and expansion of the total high-dimensional (2D-3D) structures. For the delicate balance of the various weak nonbonding interactions these structures adopted homo/hetero supramolecular synthons or both and the common R21(7) and R22(8) graph sets have been observed in all solid forms due to the interplay of hydrogen bonds and non-covalent associations.