Solvent Induced Diverse Dimensional Coordination Assemblies of Cupric Benzotriazole-5-carboxylate: Syntheses, Crystal Structures, and Magnetic Properties

Three cupric coordination assemblies [Cu(btca)(H2O)2] (1), [Cu(btca)(H2O)3.5]8·16H2O (2), and [Cu2.5(btca)1.5(Hbtca)0.5(μ-Cl)0.5(μ3–OH)(H2O)]·H2O (3) have been solvothermally synthesized by cupric salts and a bifunctional ligand benzotriazole-5-carboxylic acid (H2btca) in different solvent medium. These complexes were structurally characterized by X-ray diffraction analyses and further identified by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Single crystal structural analysis shows that these coordination compounds assembled by the almost same reactants present diverse dimensional crystal structures, wherein 1 possesses two-dimensional (2D) layers with (4.82) topology, the zero-dimensional (0D) neutral metallomacrocycle with flat octagonal geometry in 2 connects each other through hydrogen bonding to extend to be a three-dimensional (3D) nanotubular network, and 3 exhibits 3D framework with 1D honeycomb channels constructed by the strip-shaped chains containing [Cu5(μ3-OH)2(btca)4]− pentaclusters bridging to the adjacent Cu6(btca)126‑ cages. The diversity of these structures mainly stems from the versatile coordination modes of the anionic ligand in each compound, especially the 1,2,3-triazolate group: bidentate μ1,2 bridging mode in 1, bidentate μ1,3 bridging mode in 2, and tridentate μ1,2,3 bridging mode in 3, respectively. Furthermore, the magnetic properties of 1–3 have been investigated as well.