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.