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 (HL) with transition-metal ions, two novel polymeric complexes, namely, poly[diaqua[μ-2,5-bis(1H-1,2,4-triazol-1-yl)terephthalato]cobalt(II)], [Co(CHNO)(HO)], (1), and poly[[diaqua[μ-2,5-bis(1H-1,2,4-triazol-1-yl)terephthalato]nickel(II)] dihydrate], {[Ni(CHNO)(HO)]·2HO}, (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 4-subnets. The structural variation depends on the nature of the metal cations. The results of variable-temperature magnetization measurements (χT-T and χ-T) show that complexes (1) and (2) display antiferromagnetic behaviour.