Two new 4-coordinate Cu(II) chains with 1,2,3-triazole derivate as bridging ligand: Synthesis, structures and magnetic properties

Two one-dimensional Cu(II) coordination polymers, [Cu(tdp)X2]n (X = Cl(1), Br(2), tdp = 2,2’-(1H-1,2,3-triazole-1,5-diyl)dipyridine) have been synthesized and characterized, which are the first two examples of 1D CuII chains bridging by the rigid 1,2,3-triazole ligand. Compounds 1 and 2 are isomorphous. Single-crystal X-ray diffraction revealed that the ligands bridge adjacent CuII ions into an infinite one-dimensional chain with a zigzag motif in compound 1. Meanwhile, the presence of weak face-to-face π···π interactions between pyridine ring planes of two adjacent chains leads to the stabilization of the molecular packing. DC magnetic susceptibility measurements indicated the presence of weak ferromagnetic interactions (J = 1.91 cm−1 for 1, J = 0.48 cm−1 for 2) between adjacent CuII ions within the chains and antiferromagnetic interchain coupling (J′ = −0.20 cm−1 for 1, J′ = −0.10 cm−1 for 2) due to the π···π interactions.