Synthesis, structural characterization, and Hirshfeld surface analysis of three cocrystals based on flexible bis(benzimidazole) derivatives with aromatic carboxylic acids

Based on 1,3-bis(2-methylbenzimidazole)propane (L1), 1,4-bis(2-methylbenzimidazole)butane (L2) and 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L3) with aromatic carboxylic acids, three cocrystals, [(H 2 L1) 2+ ·2(H 2 btrc) 1− ] ( 1 ), [(H 2 L2) 2+ ·(H 2 btec) 2− ·2H 2 O] ( 2 ) and [(H 2 L3) 2+ ·(H 2 btec) 2− ] ( 3 ) (H 3 btrc = 1,2,4-benzenetricarboxylic acid, H 4 btec = 1,2,4,5-benzenetetracarboxylic acid) were synthesized in solution and obtained by slow evaporation. All solid products were characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Components of the crystalline phase have also been investigated in terms of Hirshfeld surfaces. The bis(benzimidazole) derivatives interlinked with aromatic carboxylates through intermolecular H-bonding and π – π interactions generate diverse 3D supramolecular networks for 1 , 2 , and 3 . The Hirshfeld surfaces and 2D fingerprint plots of three cocrystals show that 1 – 3 are stabilized by N–H···O, O–H···O, and π – π intermolecular interactions. The thermal stabilities and photoluminescence properties for cocrystals 1 – 3 were presented in the solid state.