Seven supramolecular frameworks constructed from combination of hydrogen-bonds and other non-covalent associations between organic acids and bis-imidazoles

Abstract

Seven crystalline organic acid–base adducts derived from bis(N-imidazolyl) and organic acids (2,4,6-trinitrophenol, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, oxalic acid, m-phthalic acid, and 1,5-naphthalenedisulfonic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. The seven compounds are all organic salts. In salts 1, and 3, the L1 are monoprotonated, while in 4 and 6 the L1 are diprotonated. All supramolecular architectures involve extensive classical hydrogen bonds and C–H⋯O interactions. The role of weak and strong non-covalent interactions in the crystal packing is analyzed. The complexes displayed 2D–3D framework structures for the synergistic effect of the various non-covalent interactions.The results presented herein indicate that the strength and directionality of the N–H⋯N, N–H⋯O, O–H⋯O, O–H⋯N, N–H⋯S, and O–H⋯S hydrogen bonds between the organic acids and the ditopic imidazoles are sufficient to bring about the formation of binary organic salts.