Water-soluble lanthanide coordination polymers particles with white-light emission and color tuning

Straightforward smartphone assay for quantifying tannic acid in beverages based on colour change of Eu3+/polyethyleneimine complex

Tannic acid (TA)-a natural product-is a polyphenol derivative that occurs in certain kinds of beverages. A large amount of TA could give rise to an unpleasant flavour and could negatively affect the human body by causing stomach irritation, abdominal pain, nausea, vomiting, and even death. Thus, the need exists for a simple TA detection procedure that meets specific criteria such as on-site analysis, portability, and affordability. Herein, we present a new TA assay, which is based on the fluorescent quenching effect of an efficient fluorophore, and which comprises a smartphone-integrated homemade reader system. The fluorescent polyethyleneimine-derivatised polymer (FP), a strong emitter at 510 nm, was synthesised with the aid of a facile sonication method. In the presence of Eu³⁺ ions, TA quenches the fluorescence of the FP via electrostatic interaction. A smartphone was used to capture an image of the FP undergoing fluorescence for conversion to RGB values. The blue channel was chosen for further analysis because it offered the highest R²-value compared to the red and green channels. We verified these results using a commercial spectrofluorometer and calculated the limit of detection of this assay as 87 nM and 20 nM for the homemade reader and spectrofluorometer, respectively. The detection range for TA with the proposed assay is 0.16-66.66 μM. The application of the proposed method to real beverage samples for TA detection demonstrates its analytical applicability.

Flexible and color-tunable poly(ether ether ketone) co-coordinated with Eu(III) and Tb(III) fluorescent films: Thermal stability and luminescence property

In this work, a novel kind of carboxyl-containing poly(ether ether ketone) (PEEK-COOH) was successfully synthesized and carefully characterized. Based on PEEK-COOH as macromolecular ligands, a series of luminescent rare earth polymer complexes (PEEKn-Eux-Tb1-x) were prepared and made into flexible films. The effects of the ratio of carboxyl ligand to rare earth ions on fluorescence intensity of complexes were studied and discussed. When the molar ratio was 6:1, the fluorescence emission intensity reached a maximum. Furthermore, the relative emission intensity of Tb3+ and Eu3+ binary system depended on their ratio and the intensity of fluorescence emission peak exhibited continuous change. Because of this, the color of the prepared fluorescent films could range from bright green to fire red, and each color has high purity. The fluorescence lifetime of complexes ranged from 0.428 to 0.511 ms. Absolute quantum yield of PEEK-Eu0.4-Tb0.6 was 8.4%. Beside this, these fluorescence films exhibited a high thermal stability with 5 wt. % in the range of 240–250°C, and its tensile strength was about 28 MPa. In addition, PEEKn-Eux-Tb1-x films possessed good optical transparency. All the interesting results suggested the potential application of the luminescent rare earth polymer complexes in display devices and photo-electronic devices.

Colloidal suspensions of highly luminescent lanthanide-based coordination polymer molecular alloys for ink-jet printing and tagging of technical liquids

A series of lanthanide-based coordination polymer molecular alloy colloidal dispersions usable for ink-jet printing and tagging of technical liquids.

One-step-synthesized d-gluconic acetal-based supramolecular organogelators with effective phase-selective gelation

Two effective and one-step-synthesized organogelators based on d-gluconic acetal derivatives have been developed to show phase-selective gelation behaviours towards aromatic solvents from their biphasic mixtures with water. The dominant factors that drive gelation have been studied using FT-IR and temperature-dependent ¹H NMR spectroscopy. Particularly, gelator GAA-2 in powder form could selectively congeal toluene, benzene and o-xylene at room temperature under mild stirring. Additionally, GAA-2 could gelate the aromatic solvents within 10 min and the recovery rate of the aromatic solvents could reach about 82% under a certain condition. The benefits of wide source availability, being easy to synthesize, and recyclable performance of the gelator make GAA-2 ideal for real-world remediation of aromatic solvents.

Two effective and one-step-synthesized organogelators based on d-gluconic acetal derivatives have been developed to show phase-selective gelation behaviours towards aromatic solvents from their biphasic mixtures with water.

Terpyridine-functionalized chemically cross-linked polyacrylamide hydrogel for white emission and multistimuli-responsive behaviour

A highly efficient and multifunctional white-emitting hydrogel was fabricated using a facile copolymerization process by introducing a hydrophilic terpyridine-based chromophore into a polyacrylamide network.