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Three 3-amino-1, 2, 4-triazole (atz)-based paramagnetic complexes, [Mn(atz)(pa)]n (1), {[Mn(atz)1.5(hip)]·H2O}n (2), and [Mn(H2O)2(atz)2(nb)2] (3) (H2pa = o-phthalic acid, H2hip = 5-hydroxylisophthalic acid, and Hnb = p-nitrobenzoic acid) were prepared by introducing different carboxylate-containing aromatic coligands, and structurally and magnetically characterized. Helical MnII-atz and bent MnII-pa2– chains are crosslinked by sharing the same metal sites to generate a honeycomb-shaped framework of 1. The undulated MnII-atz layers constructed from 22-member metallomacrocycles are periodically supported by ditopic hip2– ligands to lead to a pillared-layer structure of 2. In contrast, complex 3 is a centrosymmetric mononuclear entity, which is assembled into a three-dimensional supramolecular network by abundant hydrogen-bonding interactions. The structural difference of 1–3 is significantly due to the combinations of the flexible coordination modes adopted by the mixed atz and carboxylate groups. Weak and comparable antiferromagnetic couplings are observed in the nearest neighbors of 1–3, which are cooperatively transmitted either by short carboxylate and/or atz heterobridges or by weak non-covalent interactions.

Three 1H-benzimidazole-5-carboxylate (Hbic–)-based coordination polymers, {[Ni(H2O)(Hbic)2]·2H2O}n (1), {[Ni(H2O)2(Hbic)2]·3H2O}n (2), and {[Co2(H2O)4(Hbic)4]·4DMF·3H2O}n (3) were obtained by reactions of the ligand H2bic and NiII or CoII salts in the presence of different structure directing molecules. They were structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermal stability, luminescent, and magnetic measurements. Structural analysis suggests that the three polymers exhibit a 2D (4, 4) layer for 1 and 1D linear double chains for both 2 and 3 due to the variable binding modes and the specific spatial orientation of the Hbic– ligand towards the different paramagnetic metal ions, which were further aggregated into different 3D supramolecular architectures by popular hydrogen-bonding interactions. Weak and comparable antiferromagnetic couplings mediating by Hbic– bridge are observed between the neighboring spin carriers for 2 and 3, respectively. Additionally, complexes 1–3 also display different luminescence emissions at room temperature due to the ligand-to-metal charge transfer.

Two two-dimensional (2-D) trz-based coordination polymers, {[Zn(trz)(mb)]·H2O}n (1) and {[Zn(trz)(ca)]·H2O}n (2) (Htrz = 1,2,4-triazole, Hmb = 4-methylbenzoic acid, and Hca = trans-cinnamic acid), have been synthesized by diffusion method and fully structural characterized by elemental analysis, FT-IR, single-crystal X-ray crystallography, TG and fluorescence spectra. Structural analysis reveals that both complexes exhibit the analogous 2-D ZnII-trz layer motif with hydrophobic aromatic rings attached on both sides despite their different crystal system and space group (orthorhombic, Pbca for 1 and monoclinic, P21/c for 2). Interestingly, the discrete water-dimer and infinite 1-D water-chain were observed to be entrapped in the 2-D layer of 1 and 2, respectively, resulted from the different orientation of lattice water molecules as well as the patterns of hydrogen bonds involved. In addition, their similiar thermal behaviors and fluorescence emissions originated from intraligand electronic transfer were also investigated and compared.