Structural Variations Influenced by Ligand Conformation and Counteranions in Copper(II) Complexes with Flexible Bis-Triazole Ligand

Using a flexible bis-triazole ligand 1,4-bis(triazol-1-ylmethyl)benzene (L), four new copper(II) compounds {[Cu(<i>trans</i>-L)(<i>cis</i>-L)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>·4H<sub>2</sub>O}<sub><i>n</i></sub> (<b>1</b>), {[Cu(<i>cis</i>-L)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>·2H<sub>2</sub>O}<sub><i>n</i></sub> (<b>2</b>), {[Cu(<i>trans</i>-L)<sub>2</sub>]Cl<sub>2</sub>}<sub><i>n</i></sub> (<b>3</b>), and {[Cu(<i>trans</i>-L)(<i>cis</i>-L)](BF<sub>4</sub>)<sub>2</sub>}<sub><i>n</i></sub> (<b>4</b>) have been isolated. Conformations of L in <b>1</b>−<b>4</b> can be tuned as a result of changing the anion or metal/ligand ratio in the reaction system, which ultimately form a series of novel framework structures varying from 1D to 3D with different supramolecular architectures. <b>1</b> is a 1D single-chain structure, in which trinuclear water clusters link adjacent triflate anions to form 1D supramolecular helix. <b>2</b> is composed of right-helical Cu(II) bis-triazole chains, which are interlinked via copper(II) ions as hingers forming a novel 2D layered structure. Eight-member supramolecular cycles constructed by coordinated water molecules and free triflate anions are found to be embedded into the 2D planes of <b>2</b>. <b>3</b> contains 2D planar nanogrid networks stacked in an AB stacking fashion. Triple Cl···H−C hydrogen bonds reside between these 2D layers. <b>4</b> is a 3D MOF with large 1D rhombic channels with dimensionalities of 10.102 × 14.067 Å<sup>2</sup> accommodating BF<sub>4</sub><sup>−</sup> anions, which also represents the first case of metal bis-triazole compound with CdSO<sub>4</sub> topology. For <b>1−4</b>, FT-IR and elemental analysis has been carried out, and the conformational variation of L also has been briefly discussed.