Group IIB metal complexes with a multidentate N-donor tecton 3,4-bis(2-pyridyl)-5-(3-pyridyl)-1,2,4-triazole: Metal-directed assemblies, crystal structures and properties

Three novel group IIB metal complexes [Zn3(L4)2Cl6]n (1), {[Cd(L4)Cl2](H2O)}n (2) and [Hg(L4)Cl2]2 (3) with a multidentate N-donor building block 3,4-bis(2-pyridyl)-5-(3-pyridyl)-1,2,4-triazole (L4) have been prepared and characterized. Single crystal X-ray diffraction analysis reveals that 1 is a 2D layered coordination polymer constructed from the linkage of [Zn3(μ-Cl)2] trinuclear units by L4 spacers, 2 shows a 1D coordination pattern with [Cd2(μ-Cl)2] dinuclear units and L4 spacers in pair, whereas 3 has a discrete dinuclear structure. The metal ions used in the assembled processes will dominate the final coordination motifs of these complexes, as also, their extended supramolecular architectures in virtue of various secondary interactions. The solid state properties such as thermal stability and fluorescence of 1–3 are also found to be closely related to the metal centers.