A porous β-cyclodextrin-based terpolymer fluorescence sensor for in situ trinitrophenol detection

A Highly Efficient Fluorescent Sensor Based on AIEgen for Detection of Nitrophenolic Explosives

The detection of nitrophenolic explosives is important in counterterrorism and environmental protection, but it is still a challenge to identify the nitroaromatic compounds among those with a similar structure. Herein, a simple tetraphenylethene (TPE) derivative with aggregation-induced emission (AIE) characteristics was synthesized and used as a fluorescent sensor for the detection of nitrophenolic explosives (2, 4, 6-trinitrophenol, TNP and 2, 4-dinitrophenol, DNP) in water solution and in a solid state with a high selectivity. Meanwhile, it was found that only hydroxyl containing nitrophenolic explosives caused obvious fluorescence quenching. The sensing mechanism was investigated by using fluorescence titration and ¹H NMR spectra. This simple AIE-active probe can potentially be applied to the construction of portable detection devices for explosives.

Advances and Classification of Cyclodextrin-Based Polymers for Food-Related Issues

Cyclodextrins (CDs) are a good alternative to reduce or enhance different biomolecule characteristics and have demonstrated great results in food science. However, CDs present intrinsic limitations that can be solved by derivative synthesis. This review represents a survey of the state of the art of CD-based materials and their uses in food science. A deep review of the structure is carried out and different groups for ordination are suggested. After that, different applications such as cholesterol complexation or its use as sensors are reviewed. The derivatives show novel and promising activities for the industry. A critical perspective of the materials suggests that they might not present toxicity, although more studies are required. These points suggest that the research in this field will be increased in the following years.

Cucurbituril Based Luminescent Materials in Aqueous Media and Solid State

Cucurbit[n]urils, the pumpkin shaped macrocyclic host molecules possessing a hydrophobic cavity and two identical carbonyl portals, have drawn a lot of attention in recent years due to their high-affinity yet dynamic molecular recognition properties in water. The reversible and stimuli-responsive nature of their host-guest complexes imparts "smart" features leading to materials with intriguing optical, mechanical and morphological properties. In this review, we focus on the design of cucurbituril based luminescent materials in aqueous media as well in solid or film state. The design principles of fluorescent complexes, small assemblies as well as supramolecular polymers along with their stimuli-responsive properties and applications in diverse areas such as optoelectronic devices, light harvesting, anti-counterfeiting and information technology, cell imaging, etc are highlighted with selected examples from recent literature. We also discuss examples of room temperature phosphorescent materials derived from purely organic luminogens in the presence of cucurbiturils.

Two AIEE-active α-cyanostilbene derivatives containing BF2 unit for detecting explosive picric acid in aqueous medium

Two novel α-cyanostilbene derivatives bearing triphenylamine and BF₂ groups are synthesized (named TPE-B and TPE-BN). The fluorescent emissions of compounds TPE-B and TPE-BN are hypochromatically shifted and bathochromically shifted, respectively, with increasing polarity of the solvents, suggesting that the two compounds have characteristic polarity-dependent solvatochromic effects. Furthermore, they show obvious aggregation-induced emission enhancement (AIEE) phenomenon in THF/water mixture solutions. Meanwhile, compounds TPE-B and TPE-BN emit orange and yellow fluorescence in their solid states, respectively. Most significantly, in aqueous medium, compounds TPE-B and TPE-BN can selectively and sensitively detect picric acid (PA) among a number of nitroaromatic compounds, and their limits of detection (LOD) are calculated as 1.26 × 10⁻⁶ M and 1.51 × 10⁻⁶ M, respectively. The recognition mechanism for PA can be attributed to the photo-induced electron transfer (PET) process and this is supported by density functional theory (DFT) calculation. This research provides two novel compounds for the rational design of AIEE-active materials for sensing systems.

Two α-cyanostilbene derivatives bearing triphenylamine and BF₂ groups exhibit AIEE properties and can detect explosive picric acid in aqueous medium.