Halide/pseudohalide-directed cadmium(II) coordination polymers based on 3-phenyl-5-(2-pyridyl)-4-(4-pyridyl)-4H-1,2,4-triazole

Three new Cd(II) polymers [Cd-2(L-240)(2)I-4](n) (1) [Cd(L-240)(SCN)(2)](n) (2), and [Cd(L-240)(N-3)(2)](n) (3) have been synthesized via the reaction of 3-phenyl-5-(2-pyridyl)-4-(4-pyridyl)-4H-1,2,4-triazole (L-240) with CdI2 or in the presence of distinct pseudohalide anions (SCN- and N-3(-)). Single-crystal X-ray diffraction indicates that complex I features a 1D coordination chain and further forms a 2D supramolecular network extended via pi center dot center dot center dot pi stacking interactions. Complex 2 shows a 2D layered coordination network and complex 3 has a 3D diamond framework. In complexes 1-3, the Cd-II centers adopt the same octahedral geometry, whereas the L-240 ligands show distinct (mu(3), eta(2)), (mu(4), eta(3)), and (mu(2), eta(2)) binding modes, respectively. These results reveal that such polymeric networks can be well modulated by the halide anion (I-) and pseudohalide anions of SCN- and N-3(-). Thermal stability and fluorescence for complexes 1-3 have been studied. (C) 2015 Elsevier Ltd. All rights reserved.