Two isostructural Cd(II) coordination polymers showing different adsorption behaviors toward methyl orange (MO)

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.