Metal-directed supramolecular architectures based on the bifunctional ligand 2,5-bis(1H-1,2,4-triazol-1-yl)terephthalic acid

By the solvothermal reactions of 2,5-bis(1H-1,2,4-triazol-1-yl)terephthalic acid (H2 L) with transition-metal ions, two novel polymeric complexes, namely, poly[diaqua[μ4-2,5-bis(1H-1,2,4-triazol-1-yl)terephthalato]cobalt(II)], [Co(C12H6N6O4)(H2O)2] n , (1), and poly[[diaqua[μ4-2,5-bis(1H-1,2,4-triazol-1-yl)terephthalato]nickel(II)] dihydrate], {[Ni(C12H6N6O4)(H2O)2]·2H2O} n , (2), were isolated. Both polymers have been characterized by FT–IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analysis. The complexes have similar two-dimensional layered structures and coordination modes. Furthermore, the two-dimensional layered structures bear distinct intermolecular hydrogen-bonding interactions and π–π stacking interactions to form two different three-dimensional supramolecular networks based on 44-subnets. The structural variation depends on the nature of the metal cations. The results of variable-temperature magnetization measurements (χ MT−T and χ M −1−T) show that complexes (1) and (2) display antiferromagnetic behaviour.