A stable Zn-MOF with anthracene-based linker for Cr(Ⅵ)photocatalytic reduction under sunlight irradiation

The highly desired goal is to employ visible light for the photocatalytic reduction of toxic Cr(Ⅵ)to environmentally friendly Cr(Ⅲ).Metal-organic frameworks(MOFs)are considered one of the most promising materials for the photoreduction of Cr(Ⅵ).Nevertheless,developing MOFs with high stability and activity is still challenging.Herein,we report a stable Zn-based MOF(named DZU-64)with an anthracene functionalized ligand,and its reduction of Cr(Ⅵ)under sunlight irradiation was investigated.DZU-64 exhibits excellent chemical stability in pH range of 2-14 aqueous solution,and remarkable thermal stability to570℃.For the photoreduction of Cr(Ⅵ)under visible light irradiation,DZU-64 gives a record rate constant of 0.467 min^(-1)and a high Cr(Ⅵ)reduction rate of 6.68 mg Cr_((Ⅵ))g^(-1)_(cata)min^(-1)at p H 2.Moreover,under real solar light,DZU-64 can also efficiently reduce Cr(Ⅵ)to Cr(Ⅲ)while retaining its catalytic activity throughout 5 cycles without any notable decline,further demonstrating its great application prospect.By combining the photovoltaic performance tests and electron spin resonance test,the possible photoreduction of Cr(Ⅵ)mechanism in DZU-64 was analyzed.

Anthracene-based Derivatives： Synthesis, Photophysical Properties and Electrochemical Properties

A series of anthracene-based derivatives, namely, 9-（4-phenyl）anthracene（1）, 9-（4-phenylethynyl）- anthracene（2） and 9, 10-bis（phenylethynyl）anthracene（3）, was synthesized by the Suzuki/Sonogashira cross-coupling reactions in good yields. These compounds were fully characterized by X-ray crystallography, thermogravimetric analysis（TGA）, differential scanning calorimetry（DSC）, UV-Vis absorption and fiuorescence（FL） spectroscopy, as well as density functional theory（DFT） calculations. Single-crystal X-ray analysis revealed that the packing structures were influenced by the terminal substitutions. All the compounds exhibited high thermal stability（Td=221---484 ~C） and blue emission with a high quantum yield（~bf =0.20--0.75）. As the number of substituents increased, the decomposition temperatures（Td） of these compounds increased in the following order： 1〈2〈3. Experiments on the photophysical properties revealed that different substituents strongly affected the optical properties. In particular, compound lb with the electron-withdrawing group（--CHO） exhibited a larger Stokes shift（113 nm） than the other compounds. Investigation of the electrochemical properties of these compounds showed that the HOMO-LUMO energy gaps（Egap） decreased obviously as the degree of conjugation increased.

Synthesis of Bisboronic Acids and Their Selective Recognition of Sialyl Lewis X Antigen

The development of sensors that recognize Lewis oligosaccharides can help the diagnosis and early detection of cancer. Herein, we reported the design and synthesis of a series of anthracene-based bisboronic acids （9a-9e） with different N-substituents near the boronic acid unit. Among them, compound 9a could recognize sialyl Lewis X（sLex） with selectivity over other Lewis sugars, and could significantly stain sLeX-expressing HEPG2 cells with selectivity over the range of 0.1-10 μmol/L. Compound 9a possibly has two properly positioned boronic acids caused by the steric hindrance by the near N-benzyl substituent group, which empower its sLe^x selectivity and higher binding affinity.

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.