A series of coordination polymers constructed from mixed ligands for highly selective luminescence sensing of Fe3+ ions

Abstract

Four coordination polymers, namely {[Cd2(1,4-NDC)2(dbp)2]·DMF}n (1), {[Cd(1,4-NDC)(dbp)(H2O)]}n (2), {[Zn(2,6-NDC)(dbp)(H2O)]}n (3), and {[Cu(2,6-NDC)(dbp)]·0.25DMF·0.2H2O]}n (4) (1,4-NDC = 1,4-naphthalenedicarboxylic acid; 2,6-NDC = 2,6-naphthalenedicarboxylic acid; dbp = 4,4′-dimethyl-2,2′-bipyridine), were synthesized under solvothermal conditions by using a mixed-ligand strategy. Single-crystal X-ray diffraction analysis shows that compounds 1 and 2 contain similar 2D layers with {4462} topology, while compounds 3 and 4 exist as 1D chain structures, that extend into different 3D supramolecular architectures via H-bonds and interchain π∙∙∙π stacking interactions. Title compounds 1-3 exhibit strong emission at 342, 363 and 362 nm, respectively. Moreover, the selective luminescence sensing of compound 1 was investigated, owing to its excellent chemical stability and luminescence properties. Compound 1 shows remarkable fluorescence responses towards Fe3+ ions, with a detection limit of 1.0 × 10–5 M, indicating that this compound could sensitively detect trace amounts of Fe3+ in aqueous solutions through luminescence quenching.