Latest ArticlesConstructing a reliable and favorable electrode-electrolyte interface is crucial to utilize the exceptional energy storage capability in commercial lithium-ion batteries. Here, we report a facile synthesis approach for the lithium difluorophosphate (LiPO2F2) solution as an effective film-forming additive via direct adding the Li2CO3 into LiPF6 solution at 45 ℃. Benefiting from the significantly reduced interface resistance (RSEI) and charge transfer impedance (Rct) of both the cathode and anode by adding the prepared LiPO2F2 solution into a baseline electrolyte, the cycling performance of the graphite‖LiNi0.5Mn0.3Co0.2O2 pouch cell is remarkably improved under all-climate condition.
As balanced electron-rich P, C-chelating ligands, phosphine-phosphonium-ylides are considered for their ability to in situ promote palladium-catalysed direct C(sp2)-H arylation. Using methyl phosphonium salts of 2, 2'-bis(diphenylphosphino)-1, 1'-binaphtyl ("methyl-BINAPIUM") as ylide precursors under optimized reaction conditions, arylation of benzoxazole was found to proceed in moderate to high yield to give functional 2-aryl benzoxazoles. A strong anion effect of the non-salt free ylide was evidenced (TfO- > I- > PF6- ≈ salt-free). This first example of phosphonium ylides as ligands in catalytic C-H activation extends the prospect of their general implementation in homogeneous transition metal catalysis.
A new copper-thiolate cluster assembled framework [Cu2(μ4-SCH3)Cl]n (1), has been solvothermally synthesized through in situ reaction viz., in situ ligand generation and metal reduction. Compound 1 represents the first 3D framework based on Atlas-sphere functionalized by single μ2-Cl- groups. DOS calculation reveals the interaction of electronic structures. It is found that the HOMO is mainly distributed on Cl, Cu and S bonding orbitals, while the LUMO is dominated by Cu-Cl antibonding orbitals.
Chemodynamic therapy (CDT) refers to generating hydroxyl radical (·OH) in tumor sites via hydrogen peroxide (H2O2) catalyzed by transition metal ions in cancer cells under acidic environment. However, H2O2 content is not enough for effective CDT, although H2O2 content in cancer cells is higher than that of normal cells. Herein, we synthesized DOX@BSA-Cu NPs (nanoparticles) for effective CDT by providing enhanced content of H2O2 in cancer cells. The results proved Cu2+ in NPs could be reduced to Cu+ by glutathione (GSH) and effectively converted H2O2 to ·OH. Moreover, the loaded low-dose doxorubicin (DOX) in the NPs could improve the content of H2O2 and resulted in more efficient generation of ·OH in cancer cells. Thus DOX@BSA-Cu NPs exhibited higher cytotoxicity to cancer cells. This research may provide new ideas for the further studies on more effective Cu(II)-based CDT nanoagents.
To explore the effects of microenvironmental adjustments on fluorescence, a pH-sensitive nano-composite system based on fluorescence resonance energy transfer (FRET) was constructed. The model system included a modified triblock copolymer (polyhistidine-b-polyethylene glycol-b-polycaprolactone) and gold nanoparticles. A near-infrared dye was used as the donor, and spectrally matched gold nanorods, attached after C-terminus modification with α-lipoic acid, were used as the receptor to realize control of the FRET effect over the fluorescence intensity for two polymer configurational changes (i.e., "folded" and "stretched" states) in response to pH. After synthesis and characterization, we investigated the self-assembly behavior of the system. Analysis by quartz crystal microbalance revealed the pH sensitivity of the polymer, which exhibited "folding" and "stretching" states with changes in pH, providing a structural basis for the FRET effect. Fluorescence spectrophotometry investigations also revealed the regulatory impact of the assembled system on fluorescence.
Considering that hydrogen peroxide (H2O2) plays significant roles in oxidative stress, the cellular signal transduction and essential biological process regulation, the detection and imaging of H2O2 in living systems undertakes critical responsibility. Herein, we have developed a novel two-photon fluorescence turn on probe, named as Pyp-B for mitochondria H2O2 detection in living systems. Selectivity studies show that probe Pyp-B exhibit highly sensitive response toward H2O2 than other reactive oxygen species (ROS) and reactive nitrogen species (RNS) as well as biologically relevant species. The fluorescence colocalization studies demonstrate that the probe can localize in the mitochondria solely. Furthermore, as a bio-compatibility molecule, the highly selective and sensitive of fluorescence probe Pyp-B have been confirmed by its cell imaging application of H2O2 in living A549 cells and zebrafishes under the physiological conditions.
Cp*Co(Ⅲ)-catalyzed direct C-H amidation of azines has been developed. This conversion could proceed smoothly in the absence of external oxidants, acids or bases, with excellent regioselectivity and broad functional group tolerance. CO2 was released as the sole byproduct, thus providing an environmentally benign amidation process. The products obtained are important intermediates in organic synthesis.
An energy-saving and eco-friendly method for the efficient construction of various tri- and tetra-substituted pyrrolecarbonitriles through ultrasound-assisted multicomponent tandem reaction of readily available alkenes, TMSCN and N, N-disubstituted formamides within 40 min under metal-, solvent-free and mild conditions was developed. The dual role of iodine (catalyst and oxidant) notably simplified the reaction conditions and reduced the chemical waste generated.
Angiogenesis occurs during the process of tumor growth, invasion and metastasis, and is essential for the survival of solid tumors. As an integrin significantly overexpressed in human tumor vascular endothelial cells, αvβ3 is a suitable targeting site for anti-angiogenesis of tumor. We designed and prepared a selfassembling peptide (SAP) with the ability to targeting αvβ3 and self-assembly. SAP formed nanoparticles in solution and transformed into nanofibrous network once specifically binding to integrin αvβ3 on the surface of human umbilical vein endothelial cells (HUVECs). The SAP network stably anchored on HUVECs over 24 h, which consequently resulted in high-efficient inhibition of vascularization. In vitro anti-angiogenesis experiment displayed that the inhibition rate of tube-formation reached 94.9%. In vivo anti-angiogenesis array based on chick chorioallantoic membrane (CAM) model exhibited that the SAP had an inhibition rate up to 63.1%. These results indicated the outstanding anti-angiogenic ability of SAP, potentially for tumor therapy.
The deconstructive reorganization strategy for the synthesis of benzene-containing products from the kojic acid- and maltol-derived alkynes has been recently reported. In this strategy, kojic acid and maltol are analogous to the "Transformers", which can transform into benzofurans and benzaldehydes via annulation reactions. Under the synthetic standpoint, this deconstructive reorganization strategy features high atom economy, innate scalability and functional group tolerance. In the near future, we believe that this unique method will be widely investigated and other novel transformations of kojic acid and maltol will be discovered.