Multi-Mode Color-Tunable Long Persistent Luminescence in Single-Component Coordination Polymers.

Materials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti-counterfeiting, data encrypting, and other fields. However, the majority of reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal-organic coordination polymers displaying color-tunable LPL were synthesized by the self-assembly of HTzPTpy ligand with different cadmium halides (X=Cl, Br, and I). In the solid state, their LPL emission colors can be tuned by the time-evolution, as well as excitation and temperature variation, realizing multi-mode dynamic color tuning from green to yellow or green to red, and are the first such examples in single-component coordination polymer materials. Single-crystal X-ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states caused by an external heavy-atom effect. The results show that the rational introduction of different halide anions into coordination polymers can realize multi-color LPL.

Preparation of a molecularly imprinted sensor based on quartz crystal microbalance for specific recognition of sialic acid in human urine.

A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025-0.50 µmol L-1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L-1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD < 8.7 (n = 5) for the spiked urine sample obtained. Overall, this work presents how a novel QCM sensor was developed and used to detect sialic acid in human urine samples. Graphical abstract Specific recognition of sialic acid by the MIP-QCM sensor system.

The molecularly imprinted polymer supported by anodic alumina oxide nanotubes membrane for efficient recognition of chloropropanols in vegetable oils.

A new route to synthesize a covalent interaction-based molecularly imprinted polymer (MIP) material for 3-chloro-1,2-propanediol (3-MCPD) inside the nanopores of anodic alumina oxide (AAO) is presented. A series of adsorption experiments showed MIP had good extraction capacity and selectivity for 3-MCPD. In order to evaluate the usability of the MIP nanotubes membrane, a method combining AAO@MIP membrane extraction with gas chromatography - mass spectrometry (GC-MS) detection was developed for determination of chloropropanols. The limits of detection for the proposed method were 0.072 and 0.13 µg·L-1, respectively, for 3-MCPD and 1,3-DCP. The average recoveries of 3-MCPD and 1,3-DCP spiked oil samples at three concentrations (0.01, 0.05 and 0.1 mg·kg-1) were in the range of 75.6-101.0% with a RSD of 3.3-8.4%, indicating the method would be suitable for determination of chloropropanols in vegetable oils.

2-Fold Interpenetrating Bifunctional Cd-Metal-Organic Frameworks: Highly Selective Adsorption for CO2 and Sensitive Luminescent Sensing of Nitro Aromatic 2,4,6-Trinitrophenol.

A robust primitive diamond-type topology 3-D metal-organic framework (MOF) of {[Cd4(hbhdpy)2(bdc)3(DMA)2]·(H2O)4}n (1, DMA = N,N-dimethylacetamide) was constructed from the planar secondary building units of the dinuclear cadmium clusters, Cd2(µ2-O)2, and two linear organic linkers of the new multidentate Schiff base of 4-(2-hydroxy-3-methoxy-benzyli-denehydrazino-carbonyl)-N-pyridin-4-yl-benzamide (Hhbhdpy) through the solvothermal reaction. 1 presents a 2-fold interpenetrating network along with confined narrow channels and rich acylamide groups as well as potential metal open sites for excellent selective CO2 uptake over CH4/N2 and high luminescent response for 2,4,6-trinitrophenol (TNP) in DMA solution under ambient conditions. With 2-amino-1,4-dicarboxy-benzene (H2bdc-NH2) replacing H2bdc, an amine-functionalized MOF of {[Cd4(hbhdpy)2(bdc-NH2)3 (DMA)2]·(H2O)4}n (1-NH2) as an isomorphism of 1, was synthesized under the same reaction conditions. Compared with 1, the corresponding bifunctional features of 1-NH2 is more obvious. To the best of our knowledge, it is the first reported interpenetrating Cd-MOFs with highly sensitive luminescence response for TNP molecules combined with excellent selectivity for CO2/N2 and CO2/CH4.

Fabrication of a molecularly imprinted polymer immobilized membrane with nanopores and its application in determination of ß2-agonists in pork samples.

In this paper, a method for the synthesis of ractopamine molecularly imprinted polymers (MIPs) nanotube membranes on anodic alumina oxide (AAO) nanopore surface by atom transfer radical polymerization (ATRP) was presented, in which methacrylic acid (MAA) was selected as functional monomer with a polymerization rate of 1:6 between ractopamine and MAA by the computational investigations. The morphology of MIPs nanotube membranes characterized by scanning electron microscope (SEM) suggested a well growth in the AAO nanopore surface. A series of adsorption experiments revealed that the MIPs nanotube membranes showed better extraction capacity and good selectivity for ractopamine and its analogues than that of non-imprinted polymers (NIPs) nanotube membranes. In order to evaluate the usability of the MIPs nanotube membranes, a methodology by combining MIPs nanotube membranes extraction couple with high performance liquid chromatography (HPLC) detection for the determination of ß2-agonists in complex samples was developed. The linear ranges were 10-1000 µg/L for ractopamine, 100-1000 µg/L for clenbuterol, epinephrine and dopamine, and 200-1000 µg/L for terbutaline. The detection limits were within the range of 0.074-0.25 µg/L and the RSDs (n=3) were from 2.8% to 4.3%. The method was successfully applied to the analysis of ß2-agonists in spiked real samples, The recoveries of all the ß2-agonists at the two concentration levels were found to be within the range of 86.3-97.0% and 82.8-95.7%, respectively. The RSDs were within 2.7-5.7%. The results demonstrated that the proposed method is very suitable for the determination of ß2-agonists in pork samples.