Four Zn(II)–organic frameworks as luminescent probe for highly selectivity detection of CrVI ions and antibiotics

Four new luminescent metal–organic frameworks (LMOFs), {[Zn(L)]·CH3CN}n (1), [Zn2(L)2]n (2), [Zn(L) (H2O)]n (3) and {[Zn(L) (H2O)]·DMA}n (4), were assembled employing 6-(3-pyridyl)isophthalic acid (H2L) with Zn(II) ions, revealing versatile frameworks as well as various types of coordination modes of H2L. Single-crystal X-ray diffraction analyses reveal that complexes 1 and 4 exhibit a 3D dense-packing structure with a bi-nodal 3,6-connected net and an uninodal 3-connected net, respectively; while complexes 2 and 3 show 2D layered structures with a bi-nodal 3,6-connected net and an uninodal 3-connected net, respectively. Further, the solid-state luminescence properties of the complexes were measured at room temperature. The results manifest that 1 shows high selectivity and sensitivity for Cr(VI)-containing anions with detection limits of 43.77 ppm for CrO42− and 64.77 ppm for Cr2O72−. In addition, the luminescence of 1 can be quenched efficiently by trace amounts of antibiotics (dimetridazole, DTZ; sulfadiazine, SDZ; nitrofurazone, NZF; nitrofurantoin, NFT; furazolidone, FZD; chloramphenicols, INN). Complex 1 is responsive to antibiotics with detection limits of 1.35 ppm for DTZ, 1892.27 ppm for SDZ, 0.62 ppm for NZF, 0.78 ppm for NTF, FZD for 6.87 ppm.