Synthesis and Characterization of a 3D Coordination Polymer Based on Trinuclear Triangular Cu^II as Secondary Building Units

The hydrothermal reaction of Cu^II salts with 1,2,4-triazole (Htrz) in aqueous ammonia yielded a novel metal−organic framework {[Cu₃(μ₃-O)(μ₃-trz)₃(OH)(H₂O)₆]}_n (1), which was characterized by single-crystal X-ray diffraction, X-ray powder diffraction, thermogravimetric analysis, IR, and variable-temperature magnetic susceptibility. It crystallizes in cubic, space group Fd3̄c with a = 24.644(3) Å, V = 14967(3) ų, and Z = 96. Its framework is the first 3D structure using coordinative interactions constructed via trinuclear triangular Cu^II secondary building units, in which both Cu^II ions and trz ligands act as three-connected nodes to form a 6.8² net. An overall antiferromagnetic behavior was found in the compound.