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Here, we demonstrate that the first example of harmaline scaffolds serving as acceptor/acceptor-based N-C-C synthons triggered the ring opening and skeletal reconstruction of 3-vinyl benzofuranones for the construction of a library of skeletally diverse polycyclic harmaline scaffolds. These products were smoothly afforded in up to 77% yield, 420: 1 dr under catalyst-free conditions, and expanded the chemical space of biologically significant harmaline derivative species. All synthetic compounds showed cytotoxic activity against tumor cells, especially compound 3at, which exhibited selective cytotoxicity against A549 cells and lower cytotoxicity against normal cells MRC-5 and HK-2. In further mechanism research, 3at inhibited A549 cell proliferation through the G1 phase arrest, induced A549 cell apoptosis through internal and external apoptosis pathways, and suppressed the migration and invasion abilities of A549 cells. These data indicated that compound 3at is the most effective compound in the series and can serve as a promising precursor for drug development. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial water evaporation is an effective method of obtaining fresh water from seawater and wastewater. However, there are still challenges for its practical application due to insufficient light absorption capacity, large heat loss, and salt precipitation. In this work, we construct a three-dimensional (3D) arch evaporator, based on carbon cloth and Ti3C2Tx/MoSe2 photothermal composites with the synergistic effects of excellent photothermal conversion of Ti3C2Tx and the light absorption ability of MoSe2. Furthermore, the 3D arch evaporator has the merits of double-side evaporation and a double insulation barrier, which can enhance steam diffusion by air convection and optimize heat conduction by the additional air layer. Specifically, the evaporation rate of the 3D evaporator is up to 3.91 kg m−2 h−1. Meanwhile, benefiting from the capillary action and the Marangoni effect, the 3D evaporator has a stable water supply and prominent self-cleaning ability. In addition, Ti3C2Tx/MoSe2 has a good purification effect on pollutants such as heavy metal ions, organic dyes, and antibiotics due to its characteristic mesoporous structure and abundant active sites. Therefore, the 3D arch evaporator based on the Ti3C2Tx/MoSe2 photothermal layer shows great potential in solar-driven desalination and wastewater treatment. [ABSTRACT FROM AUTHOR]

An inorganic–organic hybrid probe MP-ZIF-90 was synthesized via a simple condensation reaction based on the free CHO groups of zeolitic imidazolate framework-90 (ZIF-90) and 4-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)pyridinium bromide (MP). This probe exhibited intense green emission, which was selectively quenched by the addition of ClO− anions. The response of probe MP-ZIF-90 toward ClO− was rapid (within 20 s) and sensitive, with a limit of detection (LOD) of 0.612 μM. Importantly, the utilization of the probe in the fluorescence imaging of ClO− anions in the mitochondria of living cells and zebrafish was demonstrated. [ABSTRACT FROM AUTHOR]

Here, we demonstrate the first example of natural product harmaline and its derivatives serving as useful N–C synthons in formal [3+2] cycloadditions with isothiocyanates for the construction of a library of spiropolycyclic harmaline-based hybrids containing two adjacent quaternary stereocentres. These products were smoothly afforded in up to 90% yield, 20 : 1 dr with Et3N as the catalyst under mild conditions. To the best of our knowledge, this also represents the first example of the synthesis of natural product harmaline-based spiropolycyclic scaffolds, and expands the chemical space of biologically significant harmaline derivative species. The newly synthesized structurally diverse compounds were evaluated for their in vitro anticancer activities. These studies indicate that some compounds displayed good anticancer activity against three tumor cells (A549, K562, and PC-3). Among them, compound 3cb displayed the best activity when applied to A549, which is similar to that of cisplatin. Preliminary mechanistic studies indicate that compound 3cb induces apoptosis in A549 cells through a caspase-dependent pathway. These results show that compound 3cb can be prepared as a good lead for drug development. [ABSTRACT FROM AUTHOR]

A new Ag36 nanocluster with a closed electronic structure and eight valence electrons is reported, which has a similar structure to that of an open-shell Ag34 nanocluster with three valence electrons, except that in the shell two (Ag-PPh3)+ cations replace two S2− anions specifically. The fine structural modulation leads to various levels of activity for singlet oxygen photogeneration due to the distinct optical gaps of the nanoclusters. [ABSTRACT FROM AUTHOR]

The first example of ring-opening and recyclization reaction of 3-vinyl oxindole-chromones 1 as versatile synthons, which can react with ammonia or primary aliphatic amines as binucleophiles is developed, serving as a fruitful strategy for the eco-friendly and atom-economic synthesis of a new family of skeletally diverse 2-hydroxy benzoyl pyridones 3 with high to excellent yields (70–92%). The advantages of this methodology, including the use of easily available raw materials and the catalyst-free, wide functional group tolerance, and gram-scale synthesis, make the developed methodology a practical way to access important biologically active 2-hydroxy benzoyl pyridone molecules. [ABSTRACT FROM AUTHOR]

The rational design and synthesis of hierarchical three-dimensional nanostructures with diversified compositions and fascinating morphologies can provide abundant choices and enhanced probability for applications in the energy storage field. Herein, we report an effective, metal catalyst- or surfactant-free approach for the controlled growth of hierarchical one-dimensional (1D)/two-dimensional (2D) nanostructures. The quasi-paralleled and interlaced nanosheet arrays of NiMn layered double hydroxides are grown on KCu7S4 microwires with a quasi-one-dimensional channel. The supersaturation of the system and screw dislocation-driven growth pattern of 2D materials could be key factors in determining the structure of the nanosheets arrays of NiMn LDHs. The electrochemical investigation shows that the KCu7S4@NiMn LDHs have a significantly enhanced specific capacitance (879 F g−1 at 1 mV s−1, 733.8 F g−1 at 1 A g−1) and rate capability (76.9% retention at 30 A g−1) that far exceed those of the reported individual KCu7S4 electrodes. A hybrid supercapacitor based on KCu7S4@NiMn LDH//activated graphene electrode also presents good cycle stability (an 84.8% capacitance retention after 16 000 cycles). The outstanding supercapacitor performance forebode the enormous potential of KCu7S4@NiMn LDH composites in electrochemical properties. [ABSTRACT FROM AUTHOR]

Two series of chemically and thermally stable rare-earth MOFs were constructed using trinuclear [M3(μ3-OH)(COO)6] SBUs and linear dicarboxylate linkers, which feature three-dimensional 12-connected frameworks with an hcp topology. These materials contain a large density of Lewis acidic sites, leading to high catalytic activity towards the cycloaddition of CO2 and epoxides under mild conditions. [ABSTRACT FROM AUTHOR]

Mercury (Hg2+), even an ultra-low-concentration amount in water, presents a serious environmental concern. Thus, the removal, especially Hg(ii) content at the ultratrace levels (ppb), from water is still challenging. In this work, without any pretreatment, anovel MOF material can act as a high-capacity and collectable adsorbent for the removal of Hg(ii) from water, especially for ultratrace Hg2+ ions in the ppb magnitude, mainly due to a combined effect from the pore walls functionalized by free-standing, accessible acylamide and hydroxyl units. [ABSTRACT FROM AUTHOR]

Precisely controlling the behaviours of stem cells has far-reaching application potential in clinical trials. In this study, we have developed a self-assembled monolayer (SAM) of a cyclic RGD peptide (cycRGD) and bone forming peptide-1 (BFP-1) on a quartz substrate to regulate the behaviours of mesenchymal stem cells (MSCs). The results demonstrated that cycRGD can accelerate the cell adhesion on the substrate, thereby enhancing the ability of BFP-1 in mediating the osteogenic activity. And the synergistic effect between these two functional peptides in osteogenic differentiation of MSCs was confirmed in terms of immunofluorescent staining, Alizarin Red S staining for mineralization and alkaline phosphatase (ALP) activity assay. This finding might give a new insight into designing functional substrates to regulate desired differentiation of stem cells. [ABSTRACT FROM AUTHOR]

We have synthesized a nanostructure with a platinum (Pt) nanocrystal core and a few-layer graphene shell. This graphene-encapsulated Pt nanocrystal (GPN) was fabricated through a simple chemical vapor deposition (CVD) method. After investigating the electrocatalytic activities of GPNs, their ability to act as a relatively good fuel cell catalyst was confirmed. Furthermore, to further improve their catalytic activity, a plasma-assisted nitrogen doping method was developed, and the nitrogen-doped graphene-encapsulated Pt nanocrystal (N-GPN) also demonstrated efficient electroactivities, in fact much higher than those reported for conventional Pt–graphene composite catalysts due to their small particle diameter, uniform size distribution, sufficient graphene–Pt contact, and new generation of activation sites after nitrogen doping. This simple and efficient approach could also be extended to the preparation of other alloy nanocrystals coated with a graphene shell for electrocatalytic or electrochemical sensor applications. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of 4,4′-(benzothiadiazole-4,7-diyl)dibenzoate and Zn(ii) leads to the generation of an interdigitating three-dimensional (2D + 2D → 3D) porous metal–organic framework, which displays a highly selective fluorescent enhancement with Cd2+ amongst other metal ions. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of 4,4′-(benzothiadiazole-4,7-diyl)dibenzoate and Zn(ii) leads to the generation of an interdigitating three-dimensional (2D + 2D → 3D) porous metal–organic framework, which displays a highly selective fluorescent enhancement with Cd2+ amongst other metal ions. [ABSTRACT FROM AUTHOR]

An inorganic-organic hybrid probe MP-ZIF-90 was synthesized via a simple condensation reaction based on the free CHO groups of zeolitic imidazolate framework-90 (ZIF-90) and 4-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)pyridinium bromide (MP). This probe exhibited intense green emission, which was selectively quenched by the addition of ClO - anions. The response of probe MP-ZIF-90 toward ClO - was rapid (within 20 s) and sensitive, with a limit of detection (LOD) of 0.612 μM. Importantly, the utilization of the probe in the fluorescence imaging of ClO - anions in the mitochondria of living cells and zebrafish was demonstrated.

The development of a stringent sensor to detect low levels of acetone, yielding the potential for the point-of-care clinical diagnosis of diabetes, is still a great challenge but is urgently required. Most studies have focused on Ti 3 C 2 T x , yet other types of MXenes with good performance are rare. Herein, an emerging kind of MXene, V 4 C 3 T x , has been prepared from V 4 AlC 3 via the selective etching of the Al layer using aqueous HF at room temperature (RT), and its performance as an acetone sensor is presented. A V 4 C 3 T x based acetone sensor delivers good performance, as demonstrated by its low working temperature of 25 °C, low detection limit of 1 ppm (lower than the 1.8 ppm diabetes diagnosis threshold), and high selectivity towards acetone in a mixed gas of acetone and water vapor, hopefully showing promise for application in the much faster and earlier diagnosis of diabetes. V 4 C 3 T x MXene is used for the first time in the field of acetone detection in this work, hopefully opening up a path for the investigation of applications of MXene in gas sensors, and such exciting findings distinguish V 4 C 3 T x as a comparable material to the well-known Ti 3 C 2 T x . In addition, we used DFT calculations to explore the mechanisms that result in the superior selectivity for acetone with respect to water vapor. Hopefully, the proposed mechanisms combining experimental results and theoretical study will shed light on the design and production of new high-performance acetone sensors., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A new colorimetric and fluorescence molecular chemosensor based on triazole hydrazone can be used as a multi-probe for selective detection of Al 3+ , Zn 2+ , and Cu 2+ by monitoring changes in the absorption and fluorescence spectral patterns. Results show that Al 3+ and Zn 2+ ions can induce remarkable fluorescence enhancement at pH 6.0 and pH 10.0, respectively, while the addition of Cu 2+ ions leads to a significant UV-visible absorption enhancement in the visible range at pH 6.0. In addition, the resultant Al 3+ complex could act as an 'on-off' fluorescence sensor for F - . The fluorescence sensor was also used to monitor intracellular Al 3+ , Zn 2+ , and F - in Hela cells., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Two series of chemically and thermally stable rare-earth MOFs were constructed using trinuclear [M 3 (μ 3 -OH)(COO) 6 ] SBUs and linear dicarboxylate linkers, which feature three-dimensional 12-connected frameworks with an hcp topology. These materials contain a large density of Lewis acidic sites, leading to high catalytic activity towards the cycloaddition of CO 2 and epoxides under mild conditions.

Precisely controlling the behaviours of stem cells has far-reaching application potential in clinical trials. In this study, we have developed a self-assembled monolayer (SAM) of a cyclic RGD peptide (cycRGD) and bone forming peptide-1 (BFP-1) on a quartz substrate to regulate the behaviours of mesenchymal stem cells (MSCs). The results demonstrated that cycRGD can accelerate the cell adhesion on the substrate, thereby enhancing the ability of BFP-1 in mediating the osteogenic activity. And the synergistic effect between these two functional peptides in osteogenic differentiation of MSCs was confirmed in terms of immunofluorescent staining, Alizarin Red S staining for mineralization and alkaline phosphatase (ALP) activity assay. This finding might give a new insight into designing functional substrates to regulate desired differentiation of stem cells.