Abstract
Excess and deficiency of iron(III) and antibiotics from normal permissible limits will induce serious disorders, so their detection is important but challenging. In this work, by introducing a new amino triazole ligand N-1-(4-(1H-1,2,4-triazole-1-yl)benzyl)-N-1-(2-aminoethyl)ethane-1,2-diamine (L), a series of Cd(II)-based metal-organic frameworks (MOFs) [Cd-3(BDC)(3)(DMF)(2)] (1), [Cd(L)(BDC)](2)center dot 2DMF center dot H2O (2), [NaCd2(L)(BDC)(2.5)]center dot 9H(2)O (3), [Cd-2(L)(2,6-NDC)(2)]center dot DMF center dot 5H(2)O (4) and [Cd-2(L)(BPDC)(2)]center dot DMF center dot 9H(2)O (5) were synthesized. MOFs 1, 2 and 3 obtained under the same conditions with the same auxiliary ligand (H2BDC) but different amounts of alkali (NaOH) show distinct 3D, 1D and 3D framework structures, respectively, in which L and BDC2- exhibit varied coordination modes. 4 and 5 with 3D structures were isolated by using longer auxiliary ligands of 2,6-H2NDC and H2BPDC. The porosity and excellent fluorescence performance of 3, 4 and 5 make them potential luminescent sensors for Fe(III) and antibiotics. The results show that 3, 4 and 5 represent high sensitivity for the detection of Fe(III) ions with detection limits of 155 ppb for 3, 209 ppb for 4 and 297 ppb for 5 due to the existence of open channels and chelating NH2 sites. In addition, the strong emissions of 3, 4 and 5 can be quenched efficiently by trace amounts of NFs (nitrofurazone, NZF; nitrofurantoin, NFT; furazolidone, FZD) antibiotics even in the presence of other competing antibiotics such as beta-lactams (penicillin, PCL). They are responsive to NZF with detection limits of 162 ppb for 3, 75 ppb for 4 and 60 ppb for 5.