Crystal and molecular structure of eight organic acid–base adducts from 2-methylquinoline and different acids

• Eight organic acid–base adducts have been prepared and structurally characterized.
• The different hydrogen bond interaction modes of the 2-methylquinoline and acidic compounds have been ascertained.
• All structures adopted hetero supramolecular synthons.
• The classical hydrogen bonds are the primary intermolecular force in a family of structures containing the OH⋯2-methylquinoline synthons.
• The secondary propagating interactions also play an important role in the solid-state packing of the compounds.

Eight supramolecular complexes with 2-methylquinoline and acidic components as 4-aminobenzoic acid, 2-aminobenzoic acid, salicylic acid, 5-chlorosalicylic acid, 3,5-dinitrosalicylic acid, malic acid, sebacic acid, and 1,5-naphthalenedisulfonic acid were synthesized and characterized by X-ray crystallography, IR, mp, and elemental analysis. All of the complexes are organic salts except compound 2.All supramolecular architectures of 1–8 involve extensive classical hydrogen bonds as well as other noncovalent interactions. The results presented herein indicate that the strength and directionality of the classical hydrogen bonds (ionic or neutral) between acidic components and 2-methylquinoline are sufficient to bring about the formation of binary organic acid–base adducts. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, the complexes 1–8 displayed 2D–3D framework structure.