Highly Efficient Photocatalytic Degradation of Tetracycline by Modifying UiO-66 via Different Regulation Strategies.

Wastewater containing organic pollutants cause potential harm to the environment and human health. A series of zirconium-organic frameworks (UiO-66) and their composites were synthesized by solvothermal methods, including band gap adjustment, heterojunction construction, and metal ion doping. For the model pollutant tetracycline (TC), all of the prepared catalysts could achieve effective degradation of it. Therein, the degradation efficiency of tetracycline could reach 95% under the UV irradiation with the aid of the catalyst, in which the UiO-66-NDC was modified with P-C3N4. The free radical capture experiments demonstrated that the superoxide radical (•O2-) was the main oxidizing species for the photodegradation of tetracycline. Hence, the improvement strategy of the catalyst would provide some enlightenment for the development of more efficient photocatalysts for the degradation of organic dyes in wastewater.

g-C3N4-modified Zr-Fc MOFs as a novel photocatalysis-self-Fenton system toward the direct hydroxylation of benzene to phenol.

In order to explore a green, economic, and sustainable phenol production process, a heterojunction semiconductor materials g-C3N4/Zr-Fc MOF was synthesized via an in situ synthesis method. With the synergistic effect of photocatalysis and the Fenton effect, the composite could effectively catalyze the direct hydroxylation of benzene to phenol under visible light irradiation. The yield of phenol and the selectivity were 13.84% and 99.38% under the optimal conditions, respectively, and it could still maintain high photocatalytic activity after 5 photocatalytic cycles. Therefore, the designed photocatalysis-self-Fenton system has great potential in the field of the direct hydroxylation of benzene to phenol.

An efficient photocatalyst based on H5PMo10V2O40/UiO-66-NH2 for direct hydroxylation of benzene to phenol by H2O2.

To realize the direct hydroxylation of benzene to phenol by hydrogen peroxide, an efficient photoactive catalyst system was prepared by the recombination of H5PMo10V2O40 and UiO-66-NH2. The heterpolyacid was uniformly distributed on the UiO-66-NH2, and the combination was stable. The composite could effectively photocatalyze the direct hydroxylation of benzene to phenol by H2O2 in the mixture solution of acetonitrile and acetic acid. The yield and selectivity were 14.08% and 98.8% under the optimum condition, respectively. The performance of the catalyst still maintained well after 5 catalytic cycles. Hence, the investigated catalyst system might be applied in the field of hydroxylation of benzene to phenol.

Multivalent and synergistic chitosan oligosaccharide-Ag nanocomposites for therapy of bacterial infection.

Chitosan oligosaccharide functionalized silver nanoparticles with synergistic bacterial activity were constructed as a multivalent inhibitor of bacteria. Placing the chitosan oligosaccharide on silver nanoparticles can dramatically enhance the adsorption to the bacterial membrane via multivalent binding. The multicomponent nanostructures can cooperate synergistically against gram-positive and gram-negative bacteria. The antibacterial activity was increased via orthogonal array design to optimize the synthesis condition. The synergistic bacterial activity was confirmed by fractional inhibitory concentration and zone of inhibition test. Through studies of antimicrobial action mechanism, it was found that the nanocomposites interacted with the bacteria by binding to Mg2+ ions of the bacterial surface. Then, the nanocomposites disrupted bacterial membrane by increasing the permeability of the outer membrane, resulting in leakage of cytoplasm. This strategy of chitosan oligosaccharide modification can increase the antibacterial activity of silver nanoparticles and accelerate wound healing at the same time. The nanomaterial without cytotoxicity has promising applications in bacteria-infected wound healing therapy.

1,4-Dihydropyridines: discovery of minimal AIEEgens and their mitochondrial imaging applications.

Typical aggregation-induced emission enhancement fluorogens (AIEEgens) generally are designed as propeller-shaped molecules with multiple aromatic rotors. Described herein are 1,4-dihydropyridines, which have the minimum size necessary for AIEE, containing only a single ring, synthesized through a facile biocatalysis procedure. Owing to the AIEE property, intramolecular motion can be restrained by the surrounding environment, causing the radiative channel to open up. Both the fluorescence intensities and the lifetimes of the 1,4-dihydropyridine representatives increased with increasing viscosity, and high sensitivities were observed. On the basis of the single crystal X-ray structures, density functional theory (DFT) calculations were performed to explain the mechanism of the single-ring AIEE behaviour. Moreover, a few of the neutral AIEEgens were found to possess a high specificity towards mitochondria. As an example, one of the AIEEgens exhibited superior photostability and excellent storage tolerance, allowing for real-time imaging, viscosity mapping, and long-term tracking of the dynamics of the mitochondrial morphology.

Tetraphenylethene-pyridine salts as the first self-assembling chemosensor for pyrophosphate.

We presented a novel approach for pyrophosphate (PPi) sensing. Two tetraphenylethene (TPE)-functionalised pyridine salts (TPM and TPH) were designed and synthesized. Both of them exhibited weak emission in the solution state that originates from intramolecular charge transfer (ICT) from TPE to the pyridine; the addition of PPi into the TPM aqueous solution would enhance the fluorescence intensity, which eliminates the emission quenching effect of the iodide ion by the formation of PPi-sensor nanoparticles. The detection limit of TPM was determined to be as low as 133 nM. Meanwhile, a thin solid film of TPM that could detect PPi rapidly was conveniently prepared.

Cd(II)-terpyridine-based complex as a ratiometric fluorescent probe for pyrophosphate detection in solution and as an imaging agent in living cells.

The terpyridine anthracene ligand was synthesized and characterized. is a ratiometric fluorescent probe for Cd(2+) with a recognition mechanism based on intramolecular charge transfer (ICT). An complex was isolated, and its structure was established using single-crystal XRD. The complex was able to serve as a novel reversible chemosensing ensemble to allow ratiometric response to pyrophosphate (PPi) in aqueous media. Moreover, the fluorescence imaging in living cells from these two emission channels suggested that was a ratiometric probe for Cd(2+), and the in situ generated complex was also a ratiometric ensemble for PPi detection in living cells.

Making pyrophosphate visible: the first precipitable and real-time fluorescent sensor for pyrophosphate in aqueous solution.

An in situ generated BINOL-DPA-Zn(ii) complex is presented as a chemo-sensing ensemble for the recognition of phosphate-based molecules. The ensemble showed high sensitivity and selectivity for pyrophosphates (PPi), and it could be successfully applied in imaging PPi in living cells. Notably, the ensemble exhibited a very low detection limit (95 nM) for PPi and could realize the real time detection of PPi by the naked eye through precipitate experiments. The ensemble also showed good selectivity towards ATP, and the selectivity coefficient for PPi and ATP was calculated to be 4.1/2.8.

A BINOL-based ratiometric fluorescent sensor for Zn2+ and in situ generated ensemble for selective recognition of histidine in aqueous solution.

A novel BINOL-based ratiometric fluorescent sensor (R2) is presented, which can selectively respond to Zn(2+) over Cd(2+) and other metal ions with fluorescence enhancement in aqueous solution. The R2 was successfully applied in the imaging of Zn(2+) in living cells. Additionally, the in situ generated R2-Zn(II) ensemble could further serve as a probe to distinguish histidine from other amino acids via a displacement mode.

Syntheses and highly enantioselective fluorescent recognition of α-aminocarboxylic acid anions using chiral oxacalix[2]arene[2]bisbinaphthes.

The triazine-based bisbinaphthyl crown ethers oxacalix[2]arene[2]bisbinaphthes R-1, R-2, R-3 and S-1, S-2, S-3 were synthesized. The interactions of these compounds with various α-aminocarboxylic acid anions were studied. The crown ethers were found to carry out highly enantioselective fluorescent recognition of α-aminocarboxylic acid anions. It is observed that within a certain concentration range, one enantiomer of the chiral α-aminocarboxylic acid anions can increase the fluorescence intensity of the crown ethers by fivefold to sixfold, whereas the other enantiomer scarcely enhances the fluorescence. Such unusually high enantioselective responses make these crown ethers very attractive as fluorescent sensors in determining the enantiomeric composition of α-aminocarboxylic acid anions.