Four Different Dimensional Zn(II) Coordination Polymers As Fluorescent Sensor for Detecting Hg2+, Cr2O72- in Aqueous Solution

Four Zn(II) coordination polymers (CPs), [Zn(4-pzpt)2(H2O)]n (1), {[Zn(4-pzpt)2]·CH3OH}n (2), [Zn2(4-pzpt)2(suc)(H2O)]n (3) and [Zn2(4-pzpt)2(ndc)]n (4) were obtained from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt), 1,4-Naphthalenedicarboxylic acid (H2ndc) and succinic acid (H2suc) ligands. Structural analysis reveals that 1 represents a five coordinated 0D structure. 2 possess a network featuring 2D 44 grid-like layers structure. 3 displays a network featuring 2D (63)-hcb layered structure. 4 shows a rare 3D (4,4)-connected topology with a Schläfli symbol of (4.64.7)2(64.72). Complexes 1 and 2 can mutual conversion between different solvent ratios. Luminescence properties reveal that 1 and 2 exhibit excellent selectivity for Hg2+ and Cr2O72- ions in aqueous solution, in which suggests that 1 and 2 is a promising multifunctional sensing materials. The possible sensing mechanism is also discussed.