RESUMO
A luminescent 1D coordination polymer (CP) [Zn2L2(H2O)4]·H2O (1, H2L = 1-(4-carboxyphenyl)-1H-pyrazole-3-carboxylic acid) was prepared by a solvothermal method. 1 shows excellent fluorescence properties and has an obvious fluorescence "turn-on" phenomenon for saccharin (SAC), 2-thiazolidinethione-4-carboxylic acid (TTCA), and periodate (IO4-). Between 0 and 60 µM concentration range of SAC, the fluorescence enhancement efficiency (KEC) of 1 reaches 1.00 × 105 M-1 with the limit of detection (LOD) of 90 nM. 1 is the first CP-based sensing material for SAC detection. For TTCA detection, the KEC is 2.73 × 105 M-1 at the 25-80 µM concentration range, and the LOD is 33 nM, the lowest LOD among the sensors that detect TTCA at present. For IO4- ion detection, when the IO4- ion concentration ranges from 0 to 10 µM, the KEC is 2.34 × 105 M-1 and the LOD is as low as 39 nM. In order to better understand the sensing phenomenon, we also discuss in detail the sensing mechanisms for SAC, TTCA, and IO4- ions.
RESUMO
Reports about the detection of antibiotic aztreonam (ATM) are very rare. Herein, a fluorescent "turn-on" sensing coordination polymer 1 for ATM is described. The good linear relationship between the luminescence intensity and ATM concentration (0-0.135 mM) gave the slope of 20 380 M-1 and detection limit of 4.44 × 10-7 M. This work is of great significance, not only because 1 is a sensing material for ATM with excellent selectivity, sensitivity, anti-interference ability and recoverability, but also because it expands the catalogue of antibiotics detection.
Assuntos
Antibacterianos , Polímeros , Aztreonam , Corantes Fluorescentes , LuminescênciaRESUMO
By the solvothermal assembly of Gd3+ and 5,5'-(anthracene-9,10-diyl)diisophthalic acid (H4adip), an anthracene-based lanthanide coordination polymer (CP), [Gd2(adip)(H2adip)(NMP)2]·DMF·3H2O (1; NMP = N-methylpyrrolidone; DMF = N,N-dimethylformamide), has been prepared. It possesses a 3D framework and a strong ligand-based blue emission. 1 could be applied as a multifunctional chemical sensor for UO22+, PO43-, and 2-thiazolidinethione-4-carboxylic acid (TTCA) with excellent selectivity, sensitivity, and anti-interference. In the 0-20 µM concentration range of UO22+, the quenching constant (KSV) is 4.05 × 104 M-1 with a detection limit of 1.42 µM. Fluorescence enhancement was observed when PO43- was added to the 1-H2O suspension. The slope of the linear relationship between the PO43- concentration in the 0-35 µM concentration range and I/I0 is 3.70 × 104 M-1 with a detection limit of 1.55 µM. When the TTCA concentration is lower than 20 µM, the fluorescence quenching constant KSV is 1.77 × 104 M-1 with a detection limit of 3.25 µM, which approaches the values reported of the best CP-based sensing materials for TTCA up to now. Moreover, the fluorescence quenching or enhancement mechanism was also investigated.
RESUMO
Powerful explosive sensors play a key role in public security and environmental protection. Herein, we report a series of isostructural lanthanide coordination polymers [Ln2L1.5(NMP)2] n (LnL: Ln = Eu, Gd, Tb, Dy, Ho, and Er; H4L = [1,1':4',1â³-terphenyl]-2',4,4â³,5'-tetracarboxylic acid; NMP = N-methyl-2-pyrrolidone) and mixed-Ln LnL (Eu xTb1- xL, Eu xGd1- xL, Tb xGd1- xL, and Eu xTb0.02- xGd0.98L). Luminescence studies show that both H4L and GdL emit strong fluorescence and phosphorescence at 77 K while only fluorescence at room temperature, and TbL exhibits strong Tb3+ characteristic emission, although the energy difference between the triplet excited state of H4L (20661 cm-1) and the 5D4 energy level of Tb3+ (20500 cm-1) is very small. By doping Eu3+ and Tb3+ into GdL, we obtained Eu xTb0.02- xGd0.98L emitting warm white light. For TbL and Tb0.01Gd0.99L showing dual emission, upon addition of picric acid (PA) into their suspensions in Tris-HCl buffer, Tb3+ emission decreases slowly; however, the ligand-based emission is sharply quenched, rendering TbL and Tb0.01Gd0.99L excellent single-lanthanide and mixed-lanthanide ratiometric luminescence PA sensor materials, respectively.
