High Fluorescence Porous Organic Cage for Sensing Divalent Palladium Ion and Encapsulating Fine Palladium Nanoparticles

Porous organic cages(POCs)as an innovative type of porous molecular materials enable multifunctional applications.Herein,a fluorescence POC(denoted as 1)has been constructed by means of 5/5'-((2/5-dimethoxy-l/4-phenylene)bis(ethyne-2/1-diyl))diiso-phthalaldehyde condensing with cyclohexanediamine enantiomer with the aid of trifluoroacetic acid.1 exhibits the permanent void and prominent fluorescence with relative quantum yield of 73%confirmed by gas sorption and emission experiments,respectively.Moreover,this organic cage is capable of sensing diavalent Pd2+according to the fluorescence response to the addition of various metal ions.The dispersion of 1 in methanol containing palladium acetate was stirred at 25℃and then 80℃to reduce Pd2+ions into nanoparticles(NPs),leading to the composite(Pd@l)composed of fine Pd NPs with the size of co.1.8 nm.The catalytic nature of Pd@l over NaBH4 promoted the degeneration of nitrobenzene and congo red.This work introduces one new case of POCs with versatile properties and functions,including ion fluorescence recognition,fine Pd NPs stabilizer,and gas adsorption,enriching the family of POC-based materials.

Fluorescent Recognition of Small Organic Molecules Based on Supramolecular Aggregation/Deaggregation of Planar Cu(Ⅱ)Coordination Complex

A Cu(II)coordination complex(1)with Schiff ligand derived from diaminomaleonitrile was synthesized and characterized,in which the ligand is rigid,planar and conjugated.The complex 1 displays an interesting fluorescent property relative to solvents which can be turned-on by CH_(2)Cl_(2) and CHCl_(3) solvent molecules.The mechanism of this selective fluorescence emission has been studied based on the crystal structure and the spectrum analysis.The tuning on and off fluorescence of complex 1 can be controlled by the process of supramolecular aggregation/deag-gregation in different solvents.

Highly Selective Fluorescent Recognition towards Th4＋ Based on Coumarin-derivatized Crescent Aromatic Oligoamide

An intramolecularly hydrogen-bonded crescent aromatic oligoamide 1 bearing two coumarin residues was syn- thesized. The results from UV-vis and fluorescent spectra upon metal ions complexation demonstrated that the two fluorophores serving as parts of the shape-persistent backbone provided the molecule with high selectivity and sen- sitivity for recognition of Th4＋ over other lanthanide and uranyl ions. A 48-fold fluorescent enhancement in the in- tensity was observed at 505 nm upon adding Th4＋, while other metal cations failed to induce such a significant change. A visual detection for Th4＋ was achieved by color change. The stoichiometry of the complex formed by 1 and Th4＋ was found to be 1 ： 1 with the stability constant of（2.0±0.6） × 10^6 L·mol^-1.

Synthesis of fluorescent bisboronic acid sensors and their recognition of mono-/oligo-saccharides

Sensors capable of recognizing cell surface carbohydrates,such as sialyl Lewis X（sLe-x）,are invaluable research tools and for the diagnosis and early detection of many forms of cancer.In this paper,we report the design and synthesis of a series of bisboronic acids 6（a-f） as fluorescent sensors towards mono-/oligosaccharides.Among them,compounds 6d and 6e showed strong binding affinities with glucose and fructose,while compound 6c,in which two anthracene-based boronic acid units were linked by a hexamethylene spacer,was able to recognize sLe-x selectivity and stained HEPG2 cells at 1 μmoI/L.

Two new indole derivatives as anion receptors for detecting fluoride ion

Two new compounds（1 and 2）based on indole were successfully synthesized and characterized.They display highly selective response to Fàin aqueous DMSO medium and pure DMSO with remarkable color and fluorescent changes.Therefore,both receptors may serve as colorimetric sensors for Fàby visual detection.

A fluorescent aptasensing strategy for adenosine triphosphate detection using tris(bipyridine)ruthenium(Ⅱ) complex containing six cyclodextrin units

A sensitive label-free fluorescent aptasensing strategy for the detection of adenosine triphosphate（ATP）has been developed with a metallocyclodextrin, tris（bipyridine）ruthenium（Ⅱ） complex containing six cyclodextrin units（6CD-Ru）, which exhibited much stronger emission signal compared to the parent compound Ru（bpy）_3Cl_2. Furthermore, the emission spectrum showed that the ATP-aptamer（ss DNA）could increase the fluorescence intensity of 6CD-Ru dramatically, attributed to the interaction between aptamer and cyclodextrin, which could provide protection to the ruthenium core from the quenching of emission by oxygen in the solution. With the addition of ATP, the interaction between aptamer and cyclodextrins on 6CD-Ru was diminished, since the ATP/aptamer complex had the priority to be formed,leading to the corresponding reduction of fluorescence intensity, which could be utilized to detect ATP quantitatively. A linear relationship was displayed between the fluorescence and the logarithm of ATP concentrations in the range from 1 nmol/L to 1μmmol/L with the detection limit of 0.5 nmol/L（S/N = 3）.The proposed fluorescent aptasensing strategy exhibited high sensitivity and specificity, without any labeling or amplification procedures, and it could also be applied for the detection of many other aptamer-specific targets.