Using halogen⋯halogen interactions or C/N–H⋯Cl hydrogen bonding to direct crystal packing in tetrachlorophthalic acid with N-heterocyclic compounds

In exploring tetrachlorophthalic acid (H 2 -tcpH) with a series of N-heterocyclic compounds, eight different types of supramolecular complexes have been obtained, namely, [(H-1,10-phen)·(H-tcpH)·(H 2 -tcpH)·(CH 3 OH)] ( 1 ), [(H-Hatz)·(H-tcpH)] ( 2 ), [(H 2 -L5)·(H-tcpH) 2 ] ( 3 ), [(H-Hampym)·(H-tcpH)] ( 4 ), [(H 2 -edm)·(H-tcpH) 2 ] ( 5 ), [(H-ahmp) 2 ·(tcpH)·2(H 2 O)] ( 6 ), [(H 2 -L7)·(tcpH)·2(H 2 O)] ( 7 ), and [(H-Bim)·(H-tcpH)·(H 2 O)] ( 8 ) (in which 1,10-phen = 1,10-phenanthroline, Hatz = 3-amino-1,2,4-triazole, L5 = 1,4-bis[(2-methylimidazole-1-yl)methyl]benzene, Hampym = 2-aminopyrimidine, edm = ethylenediamine, ahmp = 2-amino-4-hydroxy-6-methylpyrimidine, L7 = 1,2-bis[(2-methylimidazole-1-yl)methyl]benzene, Bim = benzimidazole). These eight complexes displayed amusing structural characteristics and a large amount of hydrogen bonding. Of these, crystals 1–5 generated a 3D supramolecular structure through Cl⋯Cl interactions, whilst C–H⋯Cl and N–H⋯Cl hydrogen bonding exists in the 3D construction of complexes 6–8 . In addition, all the complexes were fully characterized by single crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy (IR), and thermogravimetric analysis (TGA).