Latest ArticlesVisible-light-mediated para-C–H difluoroalkylation of anilides via combination of steric effects and Lewis acid activation strategies has been developed. The addition of (C6H5O)2P(O)OH and Ag2CO3 properly tune the redox potential of ruthenium catalyst and leads to mild reaction conditions. The protocol exhibits broad functional group tolerance and allows the late-stage functionalization of complex bioactive molecules.
Lipid droplet (LD) fluorescent imaging plays an important role in the detection of lipid-related diseases. Due to their poor photostability and low hydrophobicity of currently available LD imaging fluorophores, LD imaging is limited by its short imaging period and low imaging contrast. Herein, we reasonably designed a highly lipophilic compound Cou-Flu with excellent photostability and excimer-monomer transition property. It exhibited weak excimer emission in cytoplasm, but strong monomer emission in LDs, enabling high contrast LD imaging and LD movement tracing in cells. Zebrafish imaging study demonstrated that Cou-Flu was also suitable for in vivo LD detection with excellent sensitivity. We anticipate that Cou-Flu could be widely applied to understand LD-related intracellular activities and even LD-related diseases in the future.
The macrocyclic family comprising pillar[n]arenes and cucurbit[n]urils have received much attention recently. However, studies on the construction of supramolecular complexes formed directly with derivatized pillar[n]arenes and cucurbit[n]urils are scant. Given the interest in such systems, herein we have synthesized a new type of naphthalene-derivatized pillar[n]arene NTP5 and selected Q[10] as the host molecule. The 4-[2-(1-naphthalenyl)ethenyl]pyridine of NTP5 is encapsulated by Q[10] and formed a host-guest complex in water-acetic acid (1:1) solution accompanied by enhanced fluorescence, which changed the morphology of NTP5 from a sphere to a porous form. In addition, the fluorescence of Q[10]-NTP5 can be quenched by the addition of the highly toxic pesticide paraquat (PQ), and the mechanism was shown to be the formation of a new charge transfer ternary system of Q[10]-NTP5-PQ. This work provides new ideas for the contribution of supramolecular assemblies based on derivatized pillar[n]arenes and their combination with cucurbit[n]urils and reveals their potential applications.
The direct epoxidation of propylene by O2 is a significant and challenging topic. The key factor for this homogeneous aerobic epoxidation is the activation of molecular oxygen under mild conditions. In this work, the aerobic epoxidation of propylene catalyzed by manganese porphyrins was achieved in the presence of isoprene. Isoprene contains an allyl methyl group, and the α-H can be easily removed to achieve the activation of molecular oxygen. The conversion of propylene was 38% and the selectivity toward propylene oxide (PO) was up to 87%. The role of isoprene was demonstrated, and a plausible mechanism was proposed. The protocol reported herein is expected to provide a strategy for the simultaneous preparation of propylene oxide and isoprene monoxide.
Developing efficient dual–phase emission emitters upon organoboron luminophores remains a formidable challenge due to the ubiquitous self–absorption and deleterious π-π interactions from aromatic structure. Here, a new family of benzothiazole–enolate–based organoboron luminophores (HN1–4) with effective dual–phase emission was constructed. HN4 showed almost the highest quantum yield (QY) among this type of compound so far. The three-ring–fused rigid skeleton and moderate intramolecular charge transfer (ICT) effect ensured that HN4 could give rise to extremely strong emission in any solution (QY up to 99%). X-ray crystallographic analysis showed that the twisted core structure constructed by the boronic coordination of two penta-fluorobenzene of HN4 was responsible for intense emission in the solid state (QY up to 68%). Besides, HN4 exhibited a unique response to mechanical force accompanied by a reversible change of the QY. We believe that this strategy provides beneficial inspiration and methodology to design materials with high emissive quantum yield that can be used in a variety of luminescent events.
Fluorescence image for accurate tumor label still faces challenges in cancer detection and diagnostics. Emerging evidence is indicating that glucose-regulated protein 78 (GRP78), a stress-inducible protein chaperone, is a great potential biomarker and therapeutic target for cancer. However, currently available probe for image tumor based on GRP78 has not been reported, owning to no obvious strategy in probe design towards this protein. In this paper, a hairpin-shaped peptidyl probe (pepFAM) conjugated with a 5-FAM fluorophore and a dabcyl quencher at both ends was developed, respectively. The probe was designed by performing a traditional fluorescence resonance energy transfer mechanism and employing a GRP78 specifically-binding peptide. Furthermore, the probe was used to specifically image cancer cells, and accurately image xenograft tumors in mice models. The novel fluorescent probe is expected to be a useful tool for the diagnostics of cancer.
Despite the rapid development of fluorescence detection modalities for disease diagnosis, novel fluorescent molecules and probes still face with tremendous pressure to transform before employing such fluorescent tools in the clinic. Impressively, the fluorescent probes based on the traditional fluorescent dye are expected to accelerate the transformation process. Herein, methylene blue is requisitioned to design the GSH responsive probe MB-SS-CPT elaborately. The as-synthesized MB-SS-CPT provides a dramatic optical advantage for GSH detection in vitro, cell fluorescence imaging, in vivo imaging, and antitumor therapy.
The development of out-of-equilibrium self-assembly systems using light as input fuel is highly desirable and promising for the fabrication of smart supramolecular materials. Herein, we report the construction of new artificial light-fueled dissipative molecular and macroscopic self-assembly systems based on a visible-light-responsive transient quadruple H-bonding array, which consists of an azobenzene-modified ureidopyrimidinone (UPy) module (Azo-O-UPy) and a nonphotoactive diamidonaphthyridine (DAN) derived competitive binder (Napy-1). The visible light (410 nm) irradiation can induce the E to Z isomerization of the azobenzene unit of E-Azo-O-UPy to produce Z-Azo-O-UPy with an opened UPy binding site, which can complex with Napy-1 to form a quadruply H-bonded heterodimer. The heterodimer is metastable and can be quickly disassembled in dark, owing to the fast thermal relaxation of Z-Azo-O-UPy to E-Azo-O-UPy. While introducing such transient quadruple H-bonding interaction into a linear polymer system or a polymeric gel system, light-fueled out-of-equilibrium polymeric assembly both at molecular and macro-scale can be achieved.
The increasing pollution and human demand for a cleaner environment have made achieving the environmental sustainability a current research focus. As a "green" technology, semiconductor photocatalysis is of great significance to the environmental purification. Benefiting from the unique anisotropic crystal structure and electronic properties, layered photocatalytic nanomaterials show great potential for efficient photocatalytic environmental treatment. This review comprehensively summarizes the recent progress on layered photocatalytic nanomaterials for oxidation or reduction of pollutants in water and air along with the basic understanding of related mechanisms and developments in this field. First, the existing diversified layered photocatalysts are classified, and their different synthesis and modification strategies are discussed in detail to provide a comprehensive view of the material design that affects their photocatalytic performance. Subsequently, the extensive applications of the above-mentioned layered photocatalytic nanomaterials in environmental fields are systematically summarized, including photooxidation of water and air pollutants, and photoreduction of heavy metal pollutants, NO3-, BrO3- and CO2. Finally, based on the current research achievements in layered photocatalysts for environmental remediation, the future development direction and challenges are proposed.
Efficient determination of tumor exosomes using portable devices is crucial for the establishment of facile and convenient early cancer diagnostic methods. However, it is still challenging to effectively amplify the detection signal to achieve tumor exosomes detection with high sensitivity by portable devices. To address this issue, we developed a portable multi-amplified temperature sensing strategy for highly sensitive detecting tumor exosomes based on multifunctional manganese dioxide/IR780 nanosheets (MnO2/IR780 NSs) nanozyme with high oxidase-like activity and enhanced photothermal performance. Inspiringly, MnO2/IR780 NSs were synthesized via a facile one-step method with mild experimental conditions, which not only exhibited a stronger photothermal effect than that of MnO2 but also showed excellent oxidase-like activity that can catalyze the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) to generate TMB oxide (oxTMB) with a robust photothermal property, thus conjoining with MnO2/IR780 NSs to further enhance the temperature signal. The present assay enables highly sensitive determination of tumor exosomes with the detection limit down to 5.1 × 103 particles/mL, which was comparable or superior to those of the most previously reported sensors. Furthermore, detection of tumor exosomes spiked in biological samples was successfully realized. More importantly, our method showed the recommendable portability, robust applicability, and easy manipulation. By taking advantages of these features, this high-performance photothermal sensor offered a promising alternative means for nondestructive early cancer diagnosis and treatment efficacy evaluation.