A luminescent organic cocrystal for detecting 2,4-dinitroaniline.

2,4-dinitroaniline (2,4DNBA), a significant hazardous chemical, is extensively used in industry and agriculture. The chemical accumulates in the environment for a long time, causing irreversible damage to the ecosystem. Currently, it is quite challenging to identify it by common analysis and detection techniques.

Chiral Assembly of Perovskite Nanocrystals: Sensitive Discrimination of Amino Acid Enantiomers.

Chirality is a widespread phenomenon in nature and in living organisms and plays an important role in living systems. The sensitive discrimination of chiral molecular enantiomers remains a challenge in the fields of chemistry and biology. Establishing a simple, fast, and efficient strategy to discriminate the spatial configuration of chiral molecular enantiomers is of great significance.

Synthesis of a water-stable CsPbBr perovskite for selective detection of mercury ion in water.

By using the method of low-temperature crystallization, CsPbBr perovskite nanocrystals (PNCs) coated with trifluoroacetyl lysine (Tfa-Lys) and oleamine (Olam) were synthesized in aqueous solution. The structure of the CsPbBr PNCs was characterized by many methods, such as ultraviolet (UV)-visible absorption spectrophotometer, fluorescence spectrophotometer, transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. The fluorescence emission of the CsPbBr PNCs is stable in water for about 1 day at room temperature.

Lanthanide Metal-Organic Framework Isomers with Novel Water-Boosting Lanthanide Luminescence Behaviors.

Lanthanide metal-organic frameworks (Ln-MOFs) with exceptional optical performance and structural diversity offer a unique platform for the development of luminescent materials. However, Ln-MOFs often suffer from luminescence quenching by high-vibrating oscillators, especially in aqueous solution. Thus, multiple strategies have been adopted to improve the luminescence of Ln.

Novel Lanthanide-Based Metal-Organic Framework Isomer as a Double Ratiometric Fluorescent Probe for Vanillymandelic Acid.

The concentration of vanillymandelic acid (VMA) in urine is closely related with pheochromocytoma diagnosis. Thus, it is essential to develop more accurate and convenient fluorescence sensing strategies toward VMA. Until now, the design of double ratiometric detection methods for VMA was still in the unexplored stage.

Metal-Organic Framework with Near-Infrared Luminescence for "Switch-on" Determination of Kaempferol and Quercetin by the Antenna Effect.

The establishment of a reliable and sensitive method for the detection of flavonoids, such as kaempferol (Kae) and quercetin (Que), is important and challenging in food chemistry and pharmacology because numerous structural analogues may interfere with the detection. Until now, designing an efficient switch-on fluorescence sensing strategy for Kae and Que was still in the unachievable stage. In this work, a switch-on near-infrared (NIR) luminescence sensing assay for Kae and Que was fabricated based on a metal-organic framework (MOF) called IQBA-Yb for the first time.

Reversible Photochromic Coordination Polymer by Phototriggered Subtle Molecular Conformation Variations.

Photochromic materials are constructed with molecules accompanied by structural change after triggering by light, which are of great importance and necessity for various applications. However, because of space-confinement effects, molecule stacking of these photoresponsive chromophores within coordination polymers (CPs) always results in an efficiency decrement and a response delay, and this phenomenon will lead to a poor photochromic property. Herein, a CP (named CIT-E) with a 3-fold-interpenetrating network structure, which was prepared with ()-1,2-diphenyl-1,2-bis[4-(pyridin-3-ylmethoxy)phenyl]ethene () and a CuI cluster, showed fast reversible photochromic behavior.

A turn-on NIR fluorescence sensor for gossypol based on Yb-based metal-organic framework.

The development of analytical method for selective and sensitive detection of gossypol (Gsp), an extraction from the cotton plants, is important but still challenging in food safety and medical field. Herein, we reported a turn-on near infrared (NIR) fluorescence detection strategy for Gsp based on a metal-organic framework (MOF), QBA-Yb, which was prepared from 4,4'-(quinolone-5, 8-diyl) benzoate with Yb(NO)·5HO by solvothermal synthesis. The Gsp acted as another "antenna" to sensitize the luminescence of Yb, leading to the turn-on NIR emission upon 467 nm excitation.

Rapid synthesis of cesium lead halide perovskite nanocrystals by l-lysine assisted solid-phase reaction at room temperature.

Nowadays, there are many ways to obtain cesium lead halide perovskite nanocrystals. In addition to the synthesis methods carried out in solution, the solid-phase synthesis was reported involving grinding and milling. In this paper, we synthesized luminescent CsPbBr/CsPbBr perovskite nanocrystals (PNCs) by three solid-phase synthesis methods (grinding, knocking, stirring) using l-lysine as a ligand.

Silver-Driven Coordination Self-Assembly of Tetraphenylethene Stereoisomer: Construct Charming Topologies and Their Mechanochromic Behaviors.

A series of silver coordination complexes (CCs) have been synthesized through self-assembly of five pyridine-substituted tetraphenylethylene stereoisomer ligands with silver ions (named , , , , and ). These silver CCs show distinct topologies including beaded chain frameworks, linear structures, and discrete metallacycles. The single-crystal analysis results reveal the critical role of the space distribution of the coordination site and stereoisomer ligands in controlling the silver CCs' geometry configuration and modulating the optical properties.

DNA bioassays based on the fluorescence 'turn off' of silver nanocluster beacon.

Recognition and quantification of oligonucleotide sequences play important roles in medical diagnosis. In this study, a new fluorescent oligonucleotide-stabilized silver nanocluster beacon (NCB) probe was designed for sensitive detection of oligonucleotide sequence targets. This probe contained two tailored DNA strands.

One-pot synthesis of green-emitting gold nanoclusters as a fluorescent probe for determination of 4-nitrophenol.

A hydrothermal method was applied to the synthesis of green-emitting gold nanoclusters (Au NCs) which are shown to be viable fluorescent probes for 4-nitrophenol (4-NP). The Au NCs were prepared by using thiol-β-cyclodextrin as a template. Under 365 nm excitation, their green fluorescence has a peak at 502 nm, with a narrow emission bandwidth of only 30 nm.

Fluorescent carbon quantum dots synthesized using phenylalanine and citric acid for selective detection of Fe ions.

A facile, economical and one-step hydrothermal method was used to synthesize fluorescent carbon dots by utilizing citric acid as carbon source and phenylalanine to provide nitrogen. The as-prepared fluorescence carbon dots had strong blue light emission around 440 nm. As confirmed by UVvis absorption, X-ray photoelectron spectroscopic, Fourier transform infrared spectroscopy and transmission electron microscope characterization, the carbon dots were small and very stable in water for using as a fluorescent probe.

Reversible Phase Transition of Porous Coordination Polymers.

Porous coordination polymers or metal-organic frameworks with reversible phase-transition behavior possess some attractive properties, and can respond to external stimuli, including physical and chemical stimuli, in a dynamic fashion. Their phase transitions can be triggered by adsorption/desorption of guest molecules, temperature changes, high pressure, light irradiation, and electric fields; these mainly include two types of transitions: crystal-amorphous and crystal-crystal transitions. These types of porous coordination polymers have received much attention because of their interesting properties and potential applications.

Highly selective visual sensing of copper based on fluorescence enhanced glutathione-Au nanoclusters.

A blue emission glutathione stabilized Au nanoclusters prepared by an Au/Histidine complex with ligand-exchanges method was used for sensing of copper ions. We found that the glutathione stabilized Au NCs which has fluorescence emission hundred times higher than the Au/Histidine complex and has a highly selective fluorescence quenching response to copper ion. Other common metal ions, such as mercury, lead, iron and zinc, which could obviously quench or enhance the fluorescence of Au/Histidine complex, do not interfere the sensing of copper using glutathione stabilized Au nanocluster.

Three Silver Coordination Polymers with Diverse Architectures Constructed from Pyridine Carboxylic Hydrazide Ligands.

A series of silver coordination polymers (CPs) have been synthesized through self-assembly of three pyridinecarboxylic acid hydrazide (-, -, -position) ligands with silver clusters (named Ag1-iah, Ag2-iah, and Ag3-iah). These silver CPs show different one- and two-dimensional topologies including cross-helical chains, planar network, and parallel helical chains for Ag1-iah, Ag2-iah, and Ag3-iah, respectively. The combination of experimental and computational results reveals the critical role in the space distribution of the coordination site of silver clusters and ligands in controlling the silver CPs' dimensionality and packing arrangement and modulating the optical properties and stability.

Solvent-Driven Reversible Phase Transition of a Pillared Metal-Organic Framework.

Over the last decade, the controllable reversible phase transition of functional materials has received growing interest as it shows unique suitability for various technological applications. Although many metal-organic frameworks (MOFs) possess a lamellar structure, the reversible structural transformation of MOFs between their three-dimensional (3D) phase and two-dimensional (2D) phase remains a largely unexplored area. Herein, we report for the first time a europium MOF with unprecedented reversible morphology in different solvents at room temperature.

A hydrogel directly assembled from a copper metal-organic polyhedron for antimicrobial application.

Here, we report the first example of a hydrogel directly assembled from a copper MOP by a facile ultrasonic procedure, and it exhibited excellent antibacterial activity towards Gram-negative and Gram-positive bacteria.

An Enantioselective Potentiometric Sensor for 2-Amino-1-Butanol Based on Chiral Porous Organic Cage CC3-R.

Porous organic cages (POCs) have attracted extensive attention due to their unique structures and tremendous application potential in numerous areas. In this study, an enantioselective potentiometric sensor composed of a polyvinyl chloride (PVC) membrane electrode modified with CC3-R POC material was used for the recognition of enantiomers of 2-amino-1-butanol. After optimisation, the developed sensor exhibited enantioselectivity toward -2-amino-1-butanol ( log K S , R P o t = -0.

The presence of a single-nucleotide mismatch in linker increases the fluorescence of guanine-enhanced DNA-templated Ag nanoclusters and their application for highly sensitive detection of cyanide.

Fluorescence of DNA-templated silver nanoclusters can be enhanced by more than 100-fold by placing the nanoclusters in proximity to guanine-rich DNA sequences after hybridization. We found that the fluorescence of the guanine-enhanced silver nanoclusters is not increased with the guanine-rich DNA sequence closer to the silver nanoclusters. By studying the different numbers of mismatches in the linker sequences, we found that the presence of a single-nucleotide mismatch in the linker increases fluorescence more than the complementary nucleotide.

An irreversible temperature indicator fabricated by citrate induced face-to-face assembly of silver triangular nanoplates.

Assembly of anisotropic nanoparticles which need well controlling of assembly direction and spatial arrangement is more interesting than one-dimensional nanoparticles assemblies. As confirmed by observing of transmission electron microscopy images and analysis of plasmon resonance spectrum transformations, we found that silver triangular nanoplates (TNPs) without further modification could be face-to-face assembled by citrate. The face-to-face assembly of silver TNPs could be disassembled quickly by heating at a wide temperature range from 30 to 80 °C.

Copper metal-organic polyhedra nanorods with high intrinsic peroxidase-like activity at physiological pH for bio-sensing.

Enzyme-mimicking nanomaterials (nanozymes) have been used to catalyze enzyme-like reactions for various applications. Despite these favorable properties, peroxidase-mimicking nanozymes suffer from the optimum reaction occurring in acidic solutions, which greatly limits their applications in biological systems. Herein, we demonstrate that copper Metal-Organic Polyhedra (Cu-MOP) nanorods exhibit high peroxidase-mimicking activity at a physiological pH value.

Selective fluorescence quenching of papain-Au nanoclusters by self-polymerization of dopamine.

In this paper, we synthesized a papain-stabilized fluorescent Au nanocluster (NC) probe and studied its interaction with dopamine. As fluorescence of papain-Au NCs is quenched in the presence of dopamine under alkaline conditions, we were able to establish a simple, selective analytical method for dopamine determination. By studying the fluorescence lifetime and dynamic light scattering of the NCs before and after interaction with dopamine, we found that this fluorescence quenching mechanism was possibly due to dopamine self-polymerization that produced polydopamine that cross-linked papain-Au NCs.

Chicken Egg White-stabilized Au Nanoclusters for Selective and Sensitive Detection of Hg(II).

In this paper, chicken egg white purchased from a local market without further purification was directly used to prepare fluorescent gold nanoclusters through a one-step, simple, fast and green synthesis approach for analytical purposes. The as-prepared chicken egg white stabilized gold nanocluster probe has strong red fluorescence emission, which can be quenched by mercury ions and copper ions sensitively. By using an ethylenediaminetetraacetate (EDTA) masking method, mercury ions in the range from 0.

[Fluorescence Resonance Energy Transfer Detection of Cobalt Ions by Silver Triangular Nanoplates and Rhodamine 6G].

In the present paper, the authors studied fluorescence resonance energy transfer (FRET) phenomenon between silver triangular nanoplates and bovine serum albumin (BSA)/Rhodamine 6G fluorescence complex, and established a fluorescence method for the detection of cobalt ions. We found that when increasing the silver triangular nanoplates added to certain concentrations of fluorescent bovine serum albumin (BSA)/Rhodamine 6G complex, the fluorescence of Rhodamine 6G would be quenched up to 80% due to the FRET between the quencher and donor. However, in the presence of cobalt ions, the disassociation of the fluorescent complex from silver triangular nanoplates occurred and the fluorescence of the Rhodamine 6G recovered.