Latest ArticlesThe hydroarylation reaction of terminal alkynes with arylboronic acids catalyzed by low (400 ppm) loadings of palladium has been developed. The reaction is broad in scope and high-yielding, even on multi-gram scale. It is suitable for the synthesis of alkenes labeled with deuterium, and for the late-stage modification of bioactive molecules.
Human serum albumin (HSA) has emerged as a pivotal biomarker and prognostic indicator for various human diseases. Real-time sensing and visual tracking of HSA in plasma or other biological systems will immensely facilitate the basic researchers and clinicians to better understand HSA-associated biological processes. Herein, a novel near-infrared (NIR) fluorescent probe (7-HTCF) was rationally constructed for light-up sensing and in-situ imaging of HSA in real samples, based on the principle of twisted intramolecular charge transfer (TICT). Under physiological conditions, 7-HTCF could be efficiently trapped by HSA to form a stable complex via binding on a non-drug binding site, while the complex emitted strong fluoresce signals around 670 nm. Further investigations demonstrated that 7-HTCF displayed a great combination of excellent selectivity and good chemical stability, as well as rapid fluorescent response and ultra-high sensitivity for HSA detection. Particularly, the newly developed light-up probe has been successfully utilized for quantitative detection of HSA in diluted plasma samples, while its readouts are hardly affected by the addition of therapeutic agents and herbal medicines. 7-HTCF is also successfully used for in-situ imaging of the reabsorbed HSA in living renal cells, while this dye exhibits good cell permeability and high resolution for in-situ imaging in living cells. Collectively, a novel TICT-based near-infrared fluorescent probe was devised for highly selective and ultra-sensitive sensing of HSA in plasma samples or imaging HSA in living cells, which offered a practical tool for clinical tests and for exploring HSA-associated biological processes.
Pillar[5]arene-based molecular universal joints (MUJs), bearing fused crown ether subring (MUJ1 and MUJ3) or a ring without ether oxygen atom (MUJ2), were synthesized and enantio‑differentiated. Significant chiral inversion was observed for the crown ether-fused MUJs upon the addition of equivalent cations Na+, showing an anisotropy (g) factor of 0.014, while alkyl subring-fused MUJ2 showed no CD inversions. Unprecedentedly, sodium ion triggered rolling-in motion of the subring to the pillar[5]arene cavity was verified, and the synergistic noncovalent interaction of cation-π interactions and CH···π interactions were responsible for the stabilized self-included conformers. The addition of MeOH or competitive hosts 15-crown-5 ether disassembled the complex of MUJ1 and Na+ followed by a rolling-out of the subring, which made the sodium-ion triggered chiroptical switching reversible.
The abuse of antibiotics causes severe bacterial resistance, and the shortage of antibiotics has created a global public health crisis. This situation has prompted people to develop new antibacterial agents independent of traditional antibiotics. Here, we created a series of photosensitive azobenzene-quaternary ammonium salt smart antibacterial agents by connecting azobenzene with amines with different chain lengths to improve the antibacterial selectivity of quaternary ammonium salt (QAS) and prevent the accumulation of active QAS in the environment. After trans-cis isomerization, the solubility of the title compound (compound 4) increased and the antibacterial property enhanced. The experimental results suggested that the antibacterial effect of compound 4 was significantly enhanced after 365 nm light irradiation, and it had photosensitive intelligent antibacterial activity and could be reused. Notably, we did not obtain any mutants of Staphylococcus aureus or Escherichia coli resistant to compound 4. In general, compound 4 has the advantages of high yield, photo-controllable antibacterial properties, reusability, and does not induce bacterial resistance. This photosensitive antibacterial compound provides a new idea for the construction of intelligent disinfectants and is expected to be a candidate for disinfectants in public facilities and medical architecture.
Most of carbon dots (CDs) are synthesized in solutions, but the extensive use of solvents produces too much waste, needs complex purification and results in low yield. Particularly for the popular hydrothermal/solvothermal syntheses, safety issues hinder the large-scale production of CDs. Solid phase synthesis in air seems perfect to solve the above problems once for all, but nanoparticle growth in solid phase is always difficult to control. Here we suggest a new method to synthesize CDs in SBA-15 template, just by heating single carbon sources in air. Employing single carbon sources is important, which ensures both homogeneity of the nucleation and uniformity of the nanoparticle growth. The pores confinement of SBA-15 guarantees the uniform sizes of CDs, while the catalytic effect of SBA-15 accelerates the carbonization process of precursors. The products are easily extracted from the template by ethanol, and then the template can be recycled for the next synthesis after calcination. Various CDs are synthesized in this way by using different carbon sources and SBA-15 templates with different pore diameters, respectively. The results show that, the fluorescence properties of these CDs are determined by their composition and surface states, but not the particle sizes. This work opens a new avenue to synthesize uniform CDs in solid phase with high yield, low cost and tunable luminescence.
Realizing efficient charge separation and directional transfer is a challenge for single-component semiconductors. The spatial electric field generated by dipole moment could promote charge separation. Here, three-dimensional hierarchical CuCo2S4 microspheres with lattice distortion were prepared, and lattice distortion was modulated by changing feed Co/Cu molar ratios in synthesis. CuCo2S4 showed asymmetric crystal structure, leading to generation of dipole moment. The charge separation efficiency of CuCo2S4 was related to lattice distortion, and lattice expansion was in favor for charge separation. The CuCo2S4 with feed Cu/Co molar ratio of 1:4 (CCS-4) showed the maximum lattice expansion and exhibited the highest photocatalytic activity, which was attributable to the highest charge separation efficiency and the largest specific surface area. CCS-4 can remove 95.4% of tetracycline hydrochloride within 40 min photocatalysis, and effectively improve the biodegradability of pharmaceutical wastewater. Importantly, this study provides a new vision for constructing single-component photocatalysts with high photocatalytic performance.
Aqueous rechargeable Zn//MnO2 batteries have been considered as the promising candidate for future energy storage system due to their economic and environmental merits. However, the high-performance Zn//MnO2 batteries are plagued by poor sluggish reaction kinetics and capacity degradation due to the strong electrostatic interactions and complicated reaction process. Herein, the synergistic effect of atom defects engineering and phase transformation mechanism is confirmed as the effective strategy to enhance ion/charge transfer kinetics and structural stability. Defects gradient controlling and electrochemically induced phase transformation from spinel to layered structure render the aqueous Zn//λ-MnO2 system delivers a high discharge capacity of 285 mAh/g and capacity retention of 81% after 500 cycles.
Graphene oxide (GO) with unique characteristics grasps striking potentials in both academic and industrial applications. After being released into natural waters, the dispersity and stability of GO might be altered by the chemical conditions in the receiving water bodies. In this review, we summarized that the aggregation of GO in aquatic environments is mostly dependent on properties of nanoparticles (size, structure, and functional groups) and complex water chemistry (pH, temperature, light, ionic strength, and dissolved organic matter). The knowledge about the aggregation/stability of GO is still insufficient due to the variations in GO properties and complex system of natural waters. Although studies about environmental transformation of graphene-related materials can be accessed but a systematic study taking into consideration the various factors of GO and aquatic systems responsible for aggregation of GO is still lacking. Therefore, we summarized that GO homoaggregation or heteroaggregation with other solid particles can affect the distribution in different depths of rivers and toxicity toward plankton or benthic organisms. More studies are needed to investigate the stability of GO in the long term, the effect of other nanomaterial on GO aggregation, the alteration of water constituents at different regions/time and its effect on GO aggregation, to understand the transportation and impact of GO in the environment.
Acetaminophen (APAP), a classic nonsteroidal anti-inflammatory drug (NSAID), has attracted much attention due to the overdose-induced hepatotoxicity in the past several decades. N-Acetyl-p-benzoquinone imine (NAPQI), the P450-dependent metabolism of APAP, leads to GSH depletion, protein binding, mitochondrial oxidative stress, and eventually the liver injury. Herein, we develop a Fe-based metal-organic framework (MOF) to deliver and transform acetaminophen into toxic "chemo" drug through the cascade reaction for enhanced cancer therapy. In the acidic tumor microenvironment, the Fe-based MOF collapses and releases abundant Fe ions to generate hydroxyl radicals (•OH) via Fenton reaction, subsequently catalyzing nontoxic APAP into toxic NAPQI. Meanwhile, NAPQI depletes intracellular glutathione (GSH) rapidly, leading to alleviating the antioxidant ability of cancer cells and amplifying Fenton activity. The intracellular oxidative stress and the toxic metabolite of APAP can provide a synergistic effect on antitumor activity.
Three kinds of carbonized polymer dots (CPDs) synthesized via a one-pot process from o-phenylenediamine (OPD), m-phenylenediamine (MPD) and p-phenylenediamine (PPD) exhibit excitation-wavelength independent yellow, green and red emissions, respectively. In sharp contrast, two kinds of CPDs prepared via a hydrothermal process from citric acid (CA) and diethylenetriamine (DETA) exhibit obvious excitation-wavelength dependent emissions. Through the characterization and comparison of the two types of CPDs, it is concretely revealed that the polymer structure types during the formation of CPDs can effectively control the fluorescence excitation-wavelength independence/dependence. The homogeneous polymer structures contained in CPDs contribute to excitation-wavelength independence, whereas random copolymer structures contribute to excitation-wavelength dependence. These studies are of great significance for further understanding the polymer structures and designing unique optical properties of CPDs.
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