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We describe the synthesis and characterization of a hydroxylated aza-adamantyl nitroxide radical Z-3, with the solubility in water of 170 mM at room temperature. We find that hydroxylation has no significant effect on the electronic structure and stability of aza-adamantyl nitroxides. We prepare a series of β-cyclodextrin (β-CD) derivatives which can form stoichiometric 1 : 1 inclusion complexes with Z-3, to investigate their effects on water solubility and stability of the radical upon complexation. The results indicate that water solubility of Z-3 increases by 1.4–3 times, while the radical stability somewhat decreases, depending on different β-CD substituents. Overall, sodium disulfobutylether-β-CD shows the best result in complexation with Z-3, providing water solubility >0.35 mol L−1, while maintaining the stability of the nitroxide radical with a half-life of 13.5 days at room temperature in water. [ABSTRACT FROM AUTHOR]

Lead–halide perovskite nanocrystals (PeNCs), especially those composed of iodine, suffer from degradation problems. Water vapor, oxygen, light, and heat can damage PeNCs and consequently quench their photoluminescence (PL). Thus, robust encapsulation against all these stresses is urgently required. In this study, inorganic encapsulation of mesoporous SiO2, in conjunction with a high-temperature sintering synthesis process under an inert atmosphere, is introduced. This synthesis process is compatible with various halide contents, yielding PeNCs sealed in SiO2 particles that emit PL emission covering the entire visible range from 420 to 700 nm. The PeNCs–SiO2 sample showed remarkable stability after undergoing aging tests under various exaggerated stresses as well as mitigated thermal quenching during thermal cycling. The color gamut constituted by three PeNCs–SiO2 samples approached 135.36% NTSC and 101.07% Rec. 2020, with remarkable chromatic stability. The PeNCs–SiO2 can be blended into a photoresist and remains luminous during the development procedure, which is compatible with the photolithography process; this facilitates the mass production of color conversion layers. All these advantageous features show that the material proposed herein has great potential for application in full-color displays such as micro and mini light-emitting diode displays. [ABSTRACT FROM AUTHOR]

A ruthenium carbene catalyst chelated with a 3,4-dioxocyclobut-1-ene-1,2-dithiolate ligand was synthesized and its molecular structure was determined by single-crystal X-ray diffraction. The Ru catalyst had excellent catalytic activity with high yields and good Z/E ratios for the ring opening metathesis polymerization (ROMP) of norbornene (yield: 96%/Z/E: 86 : 14) and 1,5-cyclooctadiene (yield: 86%/Z/E: 91 : 9) and for ring opening cross metathesis (ROCM) reactions of norbornene/5-norbornene-2-exo, 3-exo-dimethanol with styrene (yields: 64%–92%/Z/E: 97 : 3–98 : 2) or 4-fluorostyrene (yield: 46%–94%/Z/E: 98 : 2). The catalyst also had high Z-stereoretentivity (91 : 9–98 : 2) for cross-metathesis (CM) reactions of terminal olefins with (Z)-2-butene-1,4-diol. More importantly, the catalyst had moderate Z-stereoselectivity for homometathesis reactions of terminal olefins giving cis-olefins as the major products (Z/E ratios of 70 : 30–77 : 23). Like other Ru carbene complexes, the catalyst tolerates many different functional groups. The presented data, supported by DFT calculations, show that our catalyst, bearing a chelating 3,4-dioxocyclobut-1-ene-1,2-dithiolate ligand, exhibits higher stability towards air than Hoveyda's stereoretentive complex systems. [ABSTRACT FROM AUTHOR]

A ruthenium carbene catalyst containing a 1,2-dicarbadodecaborane(12)-1,2-dithiolate ligand was synthesized, and the structure was determined by single crystal X-ray diffraction. This new ruthenium carbene catalyst can catalyze the ring opening metathesis polymerization (ROMP) reaction of norbornene to give the corresponding Z-polymer (Z/E ratio, 98 : 2) in high yield (93%); ring opening cross metathesis (ROCM) reactions of norbornene/5-norbornene-2-exo, 3-exo-dimethanol with styrene or 4-fluorostyrene to give the corresponding Z-olefin products (Z/E ratios, 97 : 3–98 : 2), respectively, in high yields (73%–88%); cross metathesis (CM) reactions of terminal alkenes with (Z)-but-2-ene-1,4-diol to give high Z-olefin products in low yields; homometathesis reactions of terminal alkenes to give olefin products in low yields. Like other ruthenium carbene catalysts, the new complex tolerates many different functional groups. DFT calculations were also performed in order to understand the process of forming Z-olefin products and the decomposition process of catalysts. [ABSTRACT FROM AUTHOR]

An indolinooxazolidine tagged N-heterocyclic carbene Ru olefin metathesis catalyst was synthesized and the molecular structure of this new Ru complex was determined by single crystal X-ray diffraction. This complex is a homogeneous catalyst and can be recovered by controlling the polarity of the indolinooxazolidine tag. Under acidic conditions the indolinooxazolidine tag exists as an open protonated form and under basic conditions the tag is in a closed form. The distribution of this catalyst in a two-phase system can be controlled by simply changing the pH, making the recovery of this catalyst easily obtainable. [ABSTRACT FROM AUTHOR]

A series of nitrogen chelated ruthenium carbene metathesis catalysts containing an N-heterocyclic carbene (NHC) and a carbonyl group have been developed and their catalytic activities for olefin metathesis reactions were investigated. The X-ray structure of the [(H2IMes)(Cl)2Ru]C(H)CH2[p-F(C6H3)NC(CF3)(C(O)OCH2CH3)] complex shows that the carbonyl oxygen of the ester and the imine nitrogen are both coordinated to the Ru metal to give an octahedral structure. The catalytic activity of these ruthenium carbene complexes for olefin metathesis reactions was tested. Some of the complexes bearing electron withdrawing groups had high initiation rates. These complexes exhibited excellent performance for both ring-closing metathesis and cross metathesis. [ABSTRACT FROM AUTHOR]

In this project, we propose a highly effective photosensitizer that breaks through drug-resistant bacterial infections with zinc-doped carbon dots. By passing through the membrane of drug-resistant bacteria, the photosensitizers produce ROS in bacteria under the action of blue light to directly kill bacteria, so as to realize the antibacterial local treatment of drug-resistant bacteria. The experiment firstly uses an efficient one-step hydrothermal method to prepare zinc-doped red-light CDs as photosensitizers, in which zinc metal was doped to improve the optical properties of the CDs. Then we try first to use EDTA as a second-step attenuator for preparing CDs to obtain photosensitizers with high-efficiency and low toxicity. In vitro cytotoxicity tests, bacterial effect tests, and in vivo animal experiments have also demonstrated that this antibacterial method has great potential for clinical translation, with a bactericidal efficiency of up to 90%. More notably, we used this antibacterial regimen seven times repeatedly to simulate the bacterial resistance process, with a bactericidal efficiency of up to 90% every time. The result indicated that S. aureus did not develop resistance to our method, showing that our method has the potential to break through drug-resistant bacterial infections as an alternative to antibiotic candidates., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The misfolded proteins or polypeptides commonly observed in neurodegenerative diseases, including Alzheimer's disease (AD), are promising drug targets for developing therapeutic agents. To target the amyloid-β (Aβ) peptide plaques and oligomers, the hallmarks of AD, we have developed twelve amphiphilic small molecules with different hydrophobic and hydrophilic fragments. In vitro fluorescence binding assays demonstrate that these amphiphilic compounds show high binding affinity to both Aβ plaques and oligomers, and six of them exhibit selective binding toward Aβ oligomers. These amphiphilic compounds can also label the Aβ species in the brain sections of transgenic AD mice, as shown by immunostaining with an Aβ antibody. Molecular docking studies were performed to obtain structure-affinity relationships. To our delight, four amphiphilic compounds can alleviate the Cu 2+ -Aβ induced toxicity in cell viability assays. In addition, confocal fluorescence imaging studies provide evidence that two compounds, ZY-15-MT and ZY-15-OMe, can disrupt the interactions between Aβ oligomers and human neuroblastoma SH-SY5Y cell membranes. Overall, these studies strongly suggest that developing compounds with amphiphilic properties that target Aβ oligomers and modulate the Aβ oligomer-cell membrane interactions can be an effective strategy for the development of small molecule AD therapeutics., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)