Three pairs of luminescent coordination polymers based on CoII and CdII clusters for the detection of antibiotics, pesticides and chiral nitro aromatic compounds

Abstract

Three couples of coordination polymers (CPs), namely, [Co((R/S)-Hcna)₂]_n (1-D/L), [Cd₆((1R,2R/1S,2S)-cpba)₄(phen)₆(H₂O)₃]_n (2-D/L) and [Cd₂((1R,2R/1S,2S)-Hcpba)₂(phen)₂]_n (3-D/L) {(R/S)-H₂cna = (R/S)-6-(1-carboxyethoxy)-2-naphthoic acid, (1R,2R/1S,2S)-H₃cpba = (1R,2R/1S,2S)-2,2′-((5-carboxy-1,3-phenylene)bis(oxy))dipropionic acid, phen = 1,10-phenanthroline} are successfully synthesized under hydrothermal conditions. Structural analysis shows that CP 1 has a 3D 3,6-c net structure with a point symbol of (4·6²)₂(4²·6¹⁰·8³). CPs 2 and 3 are obtained under very similar reaction conditions except using different solvent ratios. The presence of the planar chelating ligand phen in CPs 2 and 3 limited the spatial growth of the structure, resulting in the formation of different 1D structures. All CPs crystallized in the chiral space group P2₁, CPs 1–3 are all SHG active. Their luminescence sensing activities for organics such as antibiotics, pesticides and nitro aromatics are also investigated. The results showed that CP 1 can effectively identify trace amounts of nitrofurans (NFs) and CP 3 has obvious recognition ability toward nitrofurans (NFs) and nitroimidazoles (NMs). Both CPs 1 and 3 could selectively detect 2,6-dichloro-4-nitroaniline (DCN). The luminescence of CPs 1 and 3 can also be quenched by (D/L)-4-nitrophenylalanine ((D/L)-NPA) and (1R,2R/1S,2S)-2-amino-1-(4-nitrophenyl)propane-1,3-diol ((1R,2R/1S,2S)-ANPO).