Transition metal coordination complexes based on V-shaped bis-triazole ligand: syntheses, structures, and properties

<p>Hydrothermal reactions of 1,3-bis(1,2,4-triazol-1-yl)benzene (btb) and M(NO₃)₂ (M = Co²⁺ (<b>1</b>), Cu²⁺ (<b>2</b>)) afforded two new coordination polymers, [Co(btb)₂(NO₃)(H₂O)]_n·NO₃·H₂O (<b>1</b>) and [Cu(btb)₂(NO₃)₂]_n (<b>2</b>), respectively. Single-crystal X-ray diffraction reveals that <b>1</b> crystallizes in the space group P2₁/m and <b>2</b> crystallizes in the space group Pī, both showing a double-stranded chain structure. The 1-D chains are interconnected via <i>π</i>⋯<i>π</i> interactions to lead to 2-D ladder-like supramolecular architectures. In addition, magnetic behavior and thermal stability of <b>1</b> and <b>2</b> have been investigated. For <b>1</b>, weak antiferromagnetic interactions are observed at low temperature, and the data obey the Curie–Weiss law <i>χ</i>_M = C/(T−θ), with C = 3.22 cm³·mol⁻¹·K and <i>θ</i> = −10.39 K. For <b>2</b>, the decrease of the <i>χ</i>T <i>vs.</i> T curve at low temperature is the result of intermolecular antiferromagnetic magnetic interactions.