Latest ArticlesAsperfilasin A (1), featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core, represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes. The enantioselective total synthesis was efficiently accomplished from the key intermediate (S)-6 with three contiguous stereocenters in 5 steps and the synthetic 1 induced G2/M-phase cell cycle arrest of HT29 cells and apoptosis of HL60 and NB4 cells by activation of caspase-3 and degradation of PARP. (S)-6, bearing three contiguous chiral centers, was efficiently constructed by a novel Nazarov cyclization reaction containing basic nitrogen, which was less developed, primarily due to the incompatibility of basic nitrogen under acidic reaction conditions. This reaction allows a wide range of pentadienone substrates containing basic nitrogen to undergo Nazarov cyclization in a single regioselective and diastereoselective manner and is capable of generating three stereocenters simultaneously. Furthermore, the mechanism of the Nazarov cyclization and the origin of the regio- and diastereoselectivity were elucidated by DFT calculations and deuteration experiments, providing valuable insights into the reaction and serving as a guide for future applications involving substrates containing basic nitrogen.
Electrocatalytic water splitting for hydrogen production is a key approach to tackling the current energy crisis. Among the catalysts, the traditional Pd@C catalysts are remarkable for their efficiency in hydrogen evolution. However, the high cost and scarcity of Pd catalysts, as well as the instability caused by the corrosiveness of carbon-based substrates, hinder their large-scale application. To overcome this challenge, an effective strategy is to construct highly dispersed Pd single atoms to improve palladium utilization and choose more stable materials as supports. In this study, TiO2−x carriers with abundant oxygen vacancies were prepared and loaded with Pd by photoreduction deposition. Adjusting the palladium content resulted in three forms of Pd-loaded TiO2−x: nanoparticles (Pd@TiO2−x(6%, 10%)), nanoclusters (Pd@TiO2−x(3%)) and single atoms (Pd@TiO2−x(1.5%)). The oxygen vacancies improved the stability of the titanium dioxide materials by providing more active hydrogen adsorption sites and increasing the affinity of Pd for active hydrogen. Single atom loading increased the frequency of oxygen holes in the support and the high activity of monatomic Pd promoted the adsorption of active hydrogen and facilitated the formation of active hydrogen intermediates. The synergistic effect of single atoms and oxygen vacancies improved the stability and catalytic activity of the composite material. Pd@TiO2−x(1.5%) showed outstanding performance in hydrogen evolution in an acidic medium with an overpotential of only 24 mV at a current density of 10 mA/cm2 and a low Tafel rise of 41.9 mV/dec. This study provides an effective strategy for the development of high-performance hydrogen evolution (HER) catalysts.
Currently, it is still a challenge to develop an organic photosensitizer (PS) with outstanding near-infrared absorption, low O2 dependence, precise tumor targeting and rapid clearance through the kidney to improve the overall outcome of phototherapy. In this study, we have designed an organic PS (NcPB) with an excellent near-infrared light absorption through a refined molecular strategy. Meanwhile, NcPB was assembled into nanoparticles with different sizes (NanoNcPB-1 and NanoNcPB-0) by a supramolecular modulation strategy. As the results, the nanoparticle with an ultra-small size (NanoNcPB-1) generated a large number of superoxide anion (O2•−) in a low-O2-dependent manner and release plenty of heat. Furthermore, the results of in vivo experiments demonstrated that NanoNcPB-1 actively accumulated in tumor tissues and showed a 92% tumor inhibition after photodynamic and photothermal combination therapy. More importantly, NanoNcPB-1 could be rapidly cleared from the body of mice via the renal pathway, which alleviates potential side effects of prolonged retention of PS in the circulation.
Metal halide perovskite nanocrystals (MHP NCs) are of great candidates in photocatalytic applications due to their extreme light utilization efficiency. However, the instability towards humid environment severely restrict their practical application. Herein, the CsPbBr3/CsPb2Br5 heteronanocrystals (HNCs) were successfully encapsulated into ZIF-8 through a thermal injection method via controlling the molar ratio of Cs+/Pb2+. The surface of ZIF-8 was then modified with hydrophobic copolymer of poly(methyl methacrylate) (PMMA) to improve the water stability. Benefiting from the intimate interfacial interaction and staggered energy band structure, the type-Ⅱ heterojunction of CsPbBr3/CsPb2Br5 guarantees efficient separation and migration of photogenerated electron/hole pairs. Meanwhile, the formation of Z-scheme heterojunction between ZIF-8 and CsPbBr3/CsPb2Br5 HNCs contributes to the adsorption and enrichment of pollutants, further accelerates the photocatalytic antibiotic degradation efficiency towards tetracycline hydrochloride (TCH) in aqueous solution. Nearly 87% of TCH (40 mg/L, 50 mL) was degraded by 40 mg catalyst within 100 min. This work offers a feasible approach in assembling high-performance MHP NCs-based efficient photocatalyst with expanding application in aqueous solution.
Intracellular bacteria (ICB), cloaked by the protective barriers of host cells, pose a formidable challenge to selective and efficient eradication. The employment of activatable photosensitizers based antibacterial photodynamic therapy (aPDT) holds significant potential for selective imaging and photo-inactivation of ICB while minimizing side effects on normal cells. Drawing inspiration from the elevated hypochlorous acid (HClO) levels in ICB infected phagocytes, herein we firstly designed and synthesized a series of HClO-responsive dinuclear Ru(Ⅱ) complexes (Ru1-Ru3) to achieve such a goal. Initially, the luminescence, 1O2 generation and aPDT activity of these Ru(Ⅱ) complexes were suppressed due to the quenching effect of the azo group, but were recovered after reaction with HClO in solutions or within ICB infected phagocytes. The detailed results revealed that Ru1 and Ru3 could not only selectively visualize ICB, but also demonstrated remarkable aPDT activity against ICB, surpassing vancomycin both in vitro and in vivo.
Pure organic materials with ultralong room-temperature phosphorescence (RTP) and persistent luminescence in broad color gamut exhibit tremendous potential and broad application prospects due to their unique optical properties. This article proposes a simple strategy, polyatomic synergistic effect, to endow persistent luminescent materials with ultralong lifetime and broad color-tunability through polyatomic synergistic effect and non-traditional phosphorescence resonance energy transfer (PRET). By leveraging the polyatomic synergistic effect to enhance the intersystem crossing (ISC) in bibenzimidazole (BBI) derivatives and suppress the non-radiative transition process, ultralong persistent room-temperature phosphorescence has been successfully achieved after incorporating BBI-Cl-M into poly(methyl methacrylate) (PMMA) to form a rigid matrix(BBI-Cl-M@PMMA). Specifically, the ester functionalized bibenzimidazole with modified chlorine on molecular skeleton (BBI-Cl-M) demonstrates a remarkable phosphorescent lifetime (τp) of up to 256.4 ms. In addition, the behaviors and mechanism of RTP via polyatomic synergistic effect have been further understood by theoretical calculation and single crystal analysis. Subsequently, utilizing BBI-Cl-M as the energy donor and Rhodamine B (RB) as the energy acceptor, persistent and multicolor organic afterglow covering from green to red has been realized successfully by simply regulating the doping composition and concentration of PRET systems. These RTP materials have also been applied in underwater afterglow emission and multilevel anti-counterfeiting technology successfully.
Photoredox-mediated reversible-deactivation radical polymerization (RDRP) is an effective approach to synthesize polymers with defined composition and architecture. Current photoinduced RDRP primarily depends on outer-sphere electron transfer or homolysis mechanisms. Herein, we describe an example of iodine-mediated RDRP facilitated by photoinduced charge transfer complex (CTC) catalysis. The approach uses cheap and easily accessible N-heterocyclic nitrenium salt (NHN+···I-) as the photoactive CTC. Upon the irradiation of visible light, NHN+···I- undergoes single electron transfer to generate NHN• and I• radicals. The NHN• radical activates dormant Pn-I polymers via inner-sphere single electron transfer, leading to the propagating Pn• radical for chain growth and the I- anion for recovering the CTC, and the I• radical deactivates the polymerization via coupling with Pn•.
Sodium metal has been widely studied in the field of batteries due to its high theoretical specific capacity (~1,166 mAh/g), low redox potential (-2.71 V compared to standard hydrogen electrode), and low-cost advantages. However, problems such as unstable solid electrolyte interface (SEI), uncontrolled dendrite growth, and side reactions between solid-liquid interfaces have hindered the practical application of sodium metal anodes (SMAs). Currently, lots of strategies have been developed to achieve stabilized sodium metal anodes. Among these strategies, modified metal current collectors (MCCs) stand out due to their unique role in accommodating volumetric fluctuations with superior structure, lowering the energy barrier for sodium nucleation, and providing guided uniform sodium deposition. In this review, we first introduced three common metal-based current collectors applied to SMAs. Then, we summarized strategies to improve sodium deposition behavior by optimally engineering the surface of MCCs, including surface loading, surface structural design, and surface engineering for functional modification. We have followed the latest research progress and summarized surface optimization cases on different MCCs and their applications in battery systems.
Degradation of nitrobenzene (NB) via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation. However, the poor stability of H2O2 limits the application of traditional Fenton reactions in soil and groundwater due to the transportation risks of H2O2. In this study, we synthesized a controlled release nano calcium peroxide (nCP) by coating it with polydopamine (PDA) as a solid H2O2 to construct a Fe(Ⅱ)/PDA@nCP Fenton-like system for contaminants degradation. The phenol-quinone transformations of catechol groups on the PDA surface facilitated the Fe(Ⅱ)/Fe(Ⅲ) cycle, resulting in enhanced generation of hydroxyl radicals (HO) and effective long-term degradation of NB. Moreover, the PDA shell modulated the nCP decomposition rate and inhibited sharp pH fluctuations, and the NB removal efficiency was achieved up to 96.8% at pH ranging from 3.0 to 9.0. This study demonstrated the promising application potential of PDA@nCP as a solid-controlled release H2O2 source in Fenton-like system for groundwater contamination remediation.
In the fight against bacterial infections, it is critical to effectively disrupt biofilms. However, disruption of biofilms becomes exceptionally difficult due to the low permeability of therapeutic agents. Herein, we present a self-propelled nanovesicle (PCL-PLG@CHX) strategy for eliminating biofilms and further expediting the healing of wounds. PCL-PLG@CHX is synthesized by assembling vesicles from amphiphilic polymers, which incorporate both poly-ε-caprolactone and guanidinated-poly-ε-lysine (PCL-PLG) and are infused with chlorhexidine (CHX). Upon application to sites of bacterial infection, PCL-PLG@CHX, abundant in guanidinium structures, effectively accumulates on the negatively charged surface of biofilms. It interacts with reactive oxygen species (ROS) within the biofilm, leading to nitric oxide (NO) production. The generated NO cannot only propel the nanovesicle to penetrate deeper into the biofilm, but also act as a signaling molecule to disperse the biofilm, working in conjunction with the subsequent release of CHX for an enhanced antibacterial impact. Following the eradication of bacteria, the residual guanidine component continues to produce small quantities of NO, facilitating angiogenesis and epithelial growth, thereby accelerating the healing of wounds. Together, our study shows that PCL-PLG@CHX utilizes the potential of guanidine moieties to efficiently break down biofilms and support tissue restoration, tackling the pivotal challenge of biofilm-related diseases.
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