Synthesis and characterization of three co-crystals of bis(benzimidazole) derivatives with aromatic dicarboxylic acids

Combination of three aromatic carboxylic acids (5-nitroisophthalic acid (H2nip), 2,6-naphthalenedicarboxylic acid (H2ndc), tetrabromoterephthalic acid (H2tbta)) and flexible bis(benzimidazole) derivatives (1,6-bis(2-methylbenzimidazol-1-yl)hexane (L1), 1,2-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L2), 1,4-bis(2-methylbenzimidazol-1-yl)butane (L3)), three co-crystals [(H2L1)2+·2(Hnip)−·H2O] (1), [(L2)·(H2ndc)] (2) and [(H2L3)2+·(tbta)2−] (3) were synthesized hydrothermally. Single-crystal X-ray diffraction, elemental analysis and IR spectra are employed to characterize 1, 2 and 3. The 2D fingerprint plots and Hirshfeld surfaces of 1, 2 and 3 indicate that the 3D supramolecular network for 1 was generated by N–H···O, O–H···O, C–H··O hydrogen bonds and π−π interactions, the 2D sheet for 2 was produced by O–H···N hydrogen bonds and π−π interactions, and C–H···O hydrogen bonds make structures more stable. For 3, the 2D supramolecular layer was yielded by N–H···O, C–H···O hydrogen bond interactions. Furthermore, thermogravimetric analyses and photoluminescence properties of three compounds were presented.