Synthesis, Crystal Structures, and Properties of Copper(II), Zinc(II), and Cadmium(II) Coordination Polymers Based on 5-Nitro-isophthalate and 1,2-(2-Pyridyl)-1,2,4-triazole.

Three coordination polymers, namely {[Cu(5-nipa) (L22)](H2O)2}n (1), [Zn(5-nipa)(L22)(H2O)]n (2), and {[Cd2(5-nipa) 2(L22)(H2O)3](H2O)3.6}n (3), were prepared under similar synthetic method based on 1,2-(2-pyridyl)-1,2,4-triazole (L22) and ancillary ligand 5-nitro-isophthalic acid (5-H2nipa) with CuII, ZnII, and CdII perchlorate, respectively. All the complexes were characterized by IR spectroscopy, elemental analysis, and powder X-ray diffraction (PXRD) patterns. Single-crystal X-ray diffraction indicates that complexes 1 and 2 show similar 1D chain structures, whereas complex 3 exhibits the 2D coordination network with hcb topology. The central metal atoms show distinct coordination arrangements ranging from distorted square-pyramid for CuII in 1, octahedron for ZnII in 2, to pentagonal- bipyramid for CdII in 3. The L22 ligand adopts the same (η3,μ2) coordination fashion in complexes 1-3, while the carboxyl groups of co-ligand 5-nipa2- adopt monodentate fashion in 1 and 2 and bidentate chelating mode in 3. These results indicate that the choice of metal ions exerts a significant influence on governing the target complexes. Furthermore, thermal stabilities of complexes 1-3 and photoluminescent properties of 2 and 3 were also studied in the solid state. [ABSTRACT FROM AUTHOR]