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.
An efficient palladium-catalyzed electrooxidation C–H acylation reaction of N-nitrosoanilines with α-oxocarboxylic acids was developed. The anodic oxidation of the Pd(Ⅱ) intermediate was found to be the key to complete the reaction. In this case, the N-nitroso group was observed to be an effective directing group for C–H activation reaction. Moreover, the synthetic transformation of derivatives of natural products (L-menthol, dehydroepiandrosterone, and pregnenolone) was successfully realized. Finally, flow electrochemical synthesis of some substrates was achieved.
Cu2-xS nanostructures have been intensively studied as outstanding chemodynamic therapy (CDT) and good photothermal therapy (PTT) antibacterial agents due to their highly efficient Cu(Ⅰ)-initiated Fenton-like catalytic activity and good photothermal conversion property. However, they still suffer from shortage of Cu(Ⅰ) supply in the long-term and comparatively low inherent photothermal conversion efficiency. Herein, we constructed a self-enhanced synergistic PTT/CDT nanoplatform (Cu1.94S@MPN) by coating Cu1.94S nanoparticles with Fe(Ⅲ)/tannic acid based metal-polyphenol networks (MPN). Activated by the acidic bacterial infection microenvironment, Cu1.94S@MPN could be decomposed to continuously release Cu(Ⅱ), Fe(Ⅲ) ions and tannic acid. As the result of tannic acid-involved Cu and Fe redox cycling, Cu(Ⅰ)/Fe(Ⅱ)-rich CDT could be achieved through the highly accelerated catalytic Fenton/Fenton-like reactions. More importantly, experimental results demonstrated that Cu1.94S@MPN exhibited both excellent photothermal antibacterial and photothermal-enhanced CDT properties to eradicate bacteria in vitro and in vivo. Overall, this novel nanotherapeutics has great potential to become a clinic candidate for anti-infective therapy in future.
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.
The hyperplasia and destruction of synovial tissue have an important impact on the development of rheumatoid arthritis (RA), the abnormal proliferation and migration of synovial fibroblast in synovial tissue is similar to tumor cells. Targeting anomalous synovial fibroblast and designing a high bioavailability nano drug delivery system can reduce the dosage for the treatment of rheumatoid arthritis and it is of great significance to reduce toxic and side effects and improve curative effect. In this experiment, the nobiletin-loaded tetrahedral framework nucleic acids cargo tank was established, carrying anti-inflammatory small molecule monomer drug nobiletin with minimal bioavailability. Both in vitro cell experiments and in vivo animal studies proved the nano cargo tank enhance the role of nobiletin in reducing the invasiveness of pathological synovial fibroblast and promote their apoptosis, effectively alleviate the disease development of rheumatoid arthritis.
Polycyclic aromatic hydrocarbons (PAHs), are regarded as molecular fragments of graphene and are facilely available through chemical synthesis. Recently, it is found collective charge density oscillations with strong induced electromagnetic field display in PAH derivatives. This phenomenon, analogue to plasmonic excitation in metal, called molecular plasmonics, arise the significant interest of physicists. Instead of discussing its rich physics, this work aims at the application of molecular plasmon-like excitations in electrochromics and optoelectronics. We found that the energy and the intensity of plasmonic-like oscillation could be largely tuned by increasing the conjugation size along both the longitude/transverse axis in PAHs. Besides, the dimeric PAH demonstrates the possibility that molecular plasmonics could be designed using PAHs as building blocks for integration into larger molecular systems. Moreover, this work straightforwardly extends the molecular plasmonic-like property from CH composed PAHs to much more versatile planar conjugation systems with heteroatoms, achieving transferring between p-type and n-type organic semiconductors. Therefore, with the natural abundance, low cost, easily chemical synthesis of PAH derivatives, we believe this work paves the way for the application of molecular plasmonic-like properties in optoelectronics.
The development of deep-red emitting lead-free metal-halide perovskites with high photoluminescence quantum yields (PLQYs) and outstanding stability remains a major challenge for displays and deep-tissue bioimaging. In this work, we report a facile and convenient solvothermal method to synthesize metal halides Cs2ZnX4 (X = Cl, Br) that however is PL innert at room temperature. Upon composition engineering utilizing Sn2+ as the dopant, the resulting Cs2ZnCl4: Sn not only emits strong deep-red PL peaked at 700 nm with the highest 99.4% PLQY among the similar materials so far, but also exhibits excellent structure stability in air (PLQY remains 96% after one year exposure to the atmosphere). Detailed experimental characterizations and theoretical calculations reveal that the deep-red emission stems from self-trapped excitons induced by the Sn2+ dopant. Particularly, triplet emission (3P2→1S0) from Sn-5s2 orbitals has been observed at low temperature due to the break of parity-forbidden transition. This work provides an important guidance for the development of deep-red light-emitting materials with low price, high efficiency and excellent stability.
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.
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.
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