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Two isostructural Cd(II) coordination polymers (CPs), namely {[Cd(L)(H2O)2](ClO4)2}n (I) and {[Cd(L)(H2O)(dca)](ClO4)}n (II), have been synthesized by assembling a multidentate building block 3,4-bis(3-pyridyl)−5-(4-pyridyl)−1,2,4-triazole (L) with Cd(ClO4)2 in the absence or presence of sodium dicyanamide (Na(dca)). Single-crystal X-ray diffraction reveals that both CPs show the similar 2D-layered structures. Interestingly, they present distinct adsorption capacities (7% for I and 18% for II) toward the anionic dye methyl orange (MO). The results indicate that complex II shows higher adsorption ability, which may be ascribed to the charge effect of cationic framework. [ABSTRACT FROM AUTHOR]

Four Cd II coordination polymers, namely {[Cd(L 334 )(Cl) 2 ](CH 3 OH)} n ( 1 ), [Cd(L 334 )(Cl)(dca)] n ( 2 ), {[Cd(L 334 )(Cl) 1.33 (N 3 ) 0.67 ](H 2 O)} n ( 3 ), and {[Cd(L 334 )(SCN) 2 (H 2 O)](H 2 O) 1.5 (CH 3 OH)} n ( 4 ), have been synthesized by the conventional reactions of CdCl 2 and 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L 334 ) or in the presence of different pseudohalides dicyanamide (dca), azide (N 3 ), and thiocyanate (SCN), respectively as auxiliary ligands. Complexes 1 – 3 exhibit the isostructural 2D layered network structures, whereas complex 4 shows a distinct 2D network with dimeric Cd II subunits. The structural discrepancy in 1 – 4 indicates the significant influence of pseudohalide anions on the structural assembly of Cd II coordination polymers with 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole. In addition, thermogravimetric and fluorescent properties for all complexes and the ligand have also been investigated. [ABSTRACT FROM AUTHOR]

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]