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A powerful and attractive route to develop novel photocatalysts for C-N bond formation involves the use of pyrrolidine as the substrate and cocatalyst simultaneously. Herein, a new polyoxometalate (POM)-based metal-organic framework, namely, [Ni6(OH)3(H2O)9(DPNDIH)(SiW9O34)]2·2H2O (SiW9Ni6-DPNDI) (DPNDI = N,N'-di(4-pyridyl)-1,4,5,8-naphthalenediimide), was prepared by incorporating a Ni6 cluster-substituted POM anion and a photosensitizer (DPNDI) into a framework. The anion···π interactions and covalent bonds between SiW9Ni6 and DPNDI are beneficial for the consecutive electron separation and transfer. Under visible-light irradiation, DPNDI can be easily excited to generate radical species DPNDI* that could be further excited in the presence of the electron donor pyrrolidine for the inert O2 activation. SiW9Ni6-DPNDI showed a high efficiency in the photocatalysis of C-N bond formation under a mild condition by the synergy of DPNDI and SiW9Ni6. The results of the reaction were confirmed by gas chromatography and 1H NMR. In addition, SiW9Ni6-DPNDI exhibited a high sustainability without an obvious change in yields after five cycles.

In this paper, a new organic–inorganic hybrid compound [Co(L)2]2[W6O19](1) (HL = 2-acetylpyridine thiosemicarbazone) was prepared and characterized. The compound 1 exhibits remarkable antibacterial activity by determination of minimum inhibitory concentration (MIC) against Staphylococcus aureus (S. aureus, 0.06 µg·mL−1) and Escherichia coli (E. coli, 0.24 µg·mL−1), respectively. Furthermore, the potential mechanism of compound 1 was studied in detail. The potential causes of bacteria death were cell wall/membrane disruption, inhibition of intracellular respiratory chain dehydrogenases (RCD) activity, destruction of reactive oxygen species (ROS) and depletion of glutathione (GSH).

The exploration of new highly efficient and durable for the oxidation of amines to imines has gained immense attention. In this work, a new polyoxometalate-based metal–organic framework (POMOF) {Cu4(C26H16N4O4)4(CH3CN)2[SiW12O40]}·4H2O (SiW-Cu-DPNDI) was constructed with a catalytic oxidant Keggin-type [SiW12O40]4− anion, a photosensitizer N,N'-bis(4-pyridylmethyl)naphthalene diimide (DPNDI) ligand, and a Cu(I) cation via self-assembling. Although single-crystal X-ray diffraction, power X-ray diffraction (PXRD), infrared (IR) spectroscopy, etc., were employed to confirm the hierarchical structure of SiW-Cu-DPNDI, critical analyses through, such as the magnetic susceptibility measurements, the Mott–Schottky measurements, and the electron spin resonance studies were successfully applied to elucidate the properties of POMOF. SiW-Cu-DPNDI was highly active in the heterogeneous photocatalysis of the oxidation of amines to imines under mild conditions. Additionally, this catalyst exhibited high stability and reusability without losing its activity during the photocatalysis. The possible mechanism of the oxidation coupling was extensively investigated under visible-light (Vis)-irradiation.

Because indiscriminate antibiotic usage has driven bacterial evolutionary selection so that there is increasing microbial resistance, there is an urgent need to develop new generations of effective antibacterial agents. Herein, we developed a facile and green strategy for the preparation of a nanostructured Fe3O4@PDA@Ni-DT composite by anchoring decatungstate-based nickel(II) complex (Ni-DT) ([Ni(HL)2]2[W10O32]·4H2O, HL = 2-acetylpyridine thiosemicarbazone) onto hybrid Fe3O4@PDA (PDA = polydopamine) nanosheets. Compared with pristine Ni-DT and Fe3O4@PDA, the Fe3O4@PDA@Ni-DT composite killed 99.3% of Gram-negative Escherichia coli and 98.8% of Gram-positive Staphylococcus aureus bacteria. Notably, the composite showed potent antibacterial activity against antibiotic-resistant E. coli bacteria (ampicillin and kanamycin). The composite retained excellent recyclable performance due to the introduction of Fe3O4 nanoparticles. The detailed antibacterial mechanism used by the hybrid Fe3O4@PDA@Ni-DT composite against E. coli indicates that the nanostructured composite played a significant role in destroying the cell membrane of bacteria, inhibiting the enzymatic activity of bacteria, and increasing bacteria-destroying oxidative stress. The current work provides an effective strategy to synthesize multifunctional decatungstate-based material for highly effective and reusable antimicrobial agents.

It is a challenge to develop new photocatalysts for high selective oxidation of primary carbon-hydrogen (C–H) bonds with O2 under mild condition. Herein, a novel hybrid K6(H2O)8H24(C26H16N4O4)8[P6W48Fe6O180]·6H2O (FeW–DPNDI) was firstly synthesized by incorporating a rare Fe-substituted trimeric Dawson derivative and photosensitizer N,N'-bis(4-pyridylmethyl)naphthalene diimide (DPNDI) via solvothermal method. In FeW–DPNDI, [P6W48Fe6O180]30– and DPNDI are orderly arranged in the three-dimensional framework by the anion···π interaction and C–H···O hydrogen bonds, that is beneficial to promote the electron transfer among components. FeW–DPNDI is a typical n-type semiconductor with the calculated energy level at 2.22 V vs. NHE of the highest occupied molecular orbital (HOMO) and – 0.57 vs. NHE of the lowest unoccupied molecular orbital (LUMO), which is theoretically feasible for the reduction O2 to O2•– because of the more negative potential of CB than the standard redox potential (E(O2•–/O2) = – 0.33 V vs. NHE). The proton conductivity of FeW–DPNDI is 2.0 × 10–4 S cm−1 at 98% relative humidity and 358 K. FeW–DPNDI exhibits special selectivity for generating benzaldehyde in the photocatalytic oxidation of stubborn C–H bond of toluene under mild condition. Moreover, FeW–DPNDI can be easily isolated from the products and reused. FeW–DPNDI is the first example of the trimmer of Fe-substituted Dawson derivative, but also the first hybrid POM explored in the activating C–H bond of toluene under white light irradiation.

The novel temperature-stable microwave dielectric ceramics of Ce0.5Sm0.5O1.75 were fabricated via the mixed oxide reaction method, with the detail information including crystal phase, microstructure, sintering behavior and microwave dielectric properties being systematically investigated. For crystal phase, all the diffraction patterns were indexed as cubic fluorite-type structure with Fm-3m (225) space group and exhibited a single phase with no obvious peak position shift. The grain growth was analyzed by density and average grain size. For microwave dielectric properties of Ce0.5Sm0.5O1.75 ceramics, the dielectric constant value (er) was dependent on density. The quality factors (Q × f values) were investigated considered with average grain size. And the temperature coefficient of resonant frequency (τf value) had no significant change during the sintering temperature range, which was found consistent with the trend of the dielectric constant value. The Ce0.5Sm0.5O1.75 ceramics sintered at 1475 °C for 4 h exhibited good microwave dielectric performances with er = 18.21, Q × f = 70,500 GHz, and τf = − 16.4 ppm/°C.

This paper reported a facile strategy to fabricate ionically crosslinked supramolecular film, in which an in situ formed chitosan ionic film was produced by post-crosslinking the chitosan chains using negatively charged anion polyoxometalate. The incorporation of polyoxometalate into the chitosan ionic system accelerated the crosslinked degree, as evidenced by an increase in surface wrinkle via scanning electron microscopy. Interestingly, the resultant supramolecular film realized the combination of prominent antimicrobial effect and excellent biocompatibility, which was considered to have enormous application potential range from biomedical to environmental science.

The gene PSEN2 encodes presenilin-2, a subunit of γ-secretase. Mutations in PSEN2 are not only related to Alzheimer's disease but are also involved in other diseases. The Chinese tree shrew (Tupaia belangeri chinensis) is a potential animal model for Alzheimer's disease, although little is known about its cDNA sequence, protein structure, and PSEN2 expression. To better understand PSEN2 in the tree shrew, we cloned this gene by rapid amplification of cDNA ends technology. Hence, we analyzed the sequence and molecular characteristics of PSEN2 mRNA, predicted its spatial structure, and analyzed its expression profiles. We found that tree shrew PSEN2 is 1539 base pairs in length and encodes 330 amino acids. It is homologous and genetically similar to humans (97.64% identity). The protein structure of tree shrew PSEN2 indicated similarities to human PSEN2, both being comprised of numerous transmembrane helices. However, tree shrew PSEN2 possesses seven α-helices, and thus lacks three compared with human PSEN2. Tree shrew PSEN2 mRNAs were ubiquitously detected in all tissues, with a tissue- and temporal-specific pattern. These results pave the way towards the function of tree shrew PSEN2, which will give insights into the mechanisms leading to neurodegenerative and other diseases in humans.

The bifunctional photocatalytic-adsorbent AgZnO/polyoxometalates (AgZnO/POMs) nanocomposites were synthesized by combining AgZnO hybrid nanoparticles and polyoxometalates [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]⋅4H2O (HL = C6H6N2O) into nanostructures via a sonochemical method. Transmission electron microscopy (TEM) indicated that AgZnO/POMs nanocomposites were uniform with narrow particle size distribution and without agglomeration. X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the nanostructure and composition of AgZnO/POMs nanocomposites. The ultraviolet–visible spectra (UV–Vis) and photoluminescence spectra (PL) confirmed excellent optical properties of the AgZnO/POMs nanocomposites. 94.13% ± 0.61 of basic magenta (BM) in aqueous solution could be removed using the AgZnO/POMs nanocomposites through adsorption and photocatalysis. The kinetic analysis showed that both the adsorption and photocatalysis process conform to pseudo-second-order kinetics. In addition, the removal rate of AgZnO/POMs nanocomposites was found to be almost unchanged after 5 cycles of use. The bifunctional photocatalytic-adsorbent AgZnO/POMs nanocomposites with high stability and cycling performance have broad application prospects in the treatment of refractory organic dye wastewater containing triphenylmethane.

MgO was designed as a new additive to optimize the microwave dielectric properties of LaNbO4 ceramics, and consequently the Q × ƒ values of LaNbO4 ceramics were effectively increased. The effects of MgO additive on phase composition, microstructure and microwave dielectric properties were discussed. LaNbO4, indexed as the main phase, had no obvious change, while the secondary phase related to MgO varied with different MgO content. The grain growth was evaluated by grain size and its distribution. The dielectric constant (er) was generally stable among the whole designed sintering temperature, but had some decrease with MgO (low permittivity) content increasing. The Q × ƒ values were not only affected by bulk densities during the sintering process, but also depended on the grain size and its distribution with different MgO contents. Sintered at 1425 °C for 4 h with x = 0.5, LaNbO4–xMgO ceramics possessed excellent performance: er = 19.8, Q × f = 94,440 GHz, τƒ = 6.1 ppm/°C.

Magnetic-fluorescent nanoparticles integrating imaging and therapeutic capabilities have unparalleled advantages in the biomedical applications. Apart from the dual ability of unique biomolecular fluorescent recognition and magnetic modes, the nanoparticle also endows combined effective therapies with high physiological stability, long-term imaging, rapid response time, and excellent circulation ability. Herein, we developed a carboxyl-functionalized magnetic nanoparticle that was further functionalized by polydopamine (PDA) and Schiff base ligand (3-aminopyridine-2-carboxaldehyde

Two-dimensional (2D) crystalline porous materials with designable structures and high surface areas are currently a hot research topic in the field of proton- and electron-conducting materials, which provide great opportunities to orderly accommodate carriers in available spaces and to accurately understand the conducting path. The 2D dual-conductive inorganic framework [Co(H2O)6]2{[Co(H2O)4]4[WZn3(H2O)2(ZnW9O34)2]}·8H2O (Co6Zn5W19) is synthesized by combining [WZn3(H2O)2(ZnW9O34)2]12- (Zn5W19) and a Co(II) ion via a hydrothermal method. Due to the presence of a consecutive H-bonding network, electrostatic interactions, and packing effects between the framework and guest molecules, Co6Zn5W19 displays a high proton conductivity (3.55 × 10-4 S cm-1 under 98% RH and 358 K) by a synergistic effect of the combined components. Additionally, a photoactuated electron injection into the semiconducting materials is an important strategy for switching electronic conductivity, because it can efficiently reduce the frameworks without destroying the crystallinity. I-V curves of a tablet of Co6Zn5W19 in the reduced and oxidized states yield conductivities of 1.26 × 10-6 and 5 × 10-8 S cm-1, respectively. Moreover, Co6Zn5W19 is also successfully applied in the photocatalytic reduction of the toxic Cr(VI) metal ion by utilizing its excellent electronic storage capacity and Baeyer-Villiger (BV) oxidation in a molecular oxygen/aldehyde system.

Herein, a polyoxometalate (POM)-based blend hydrogel system was in situ constructed by incorporating cetyltrimethylammoniumbromide (CTAB)-encapsulated POM cationic micelles to bare hydrogel matrixes followed by copolymerization of multivalent crosslinking groups. It was demonstrated that the fabricated blend hydrogel possessed tunable physicochemical properties, good swelling behavior (maximum swelling rate of 229% in buffer solution of pH 8.0), excellent local action and sustained release of POM component (release ratio achieved nearly 100% at the time of 120 min). Antibacterial activity study revealed that the introduction of POM greatly improved the bioavailability of itself, namely, leading to a more effective enhancement of therapeutic effects (survival ratio of both strains less than 5%). Besides, bactericidal rates (ca. 51%) were achieved even after six runs repeated, thereby verifying the biological application potential of this material. Finally, the practical application potentials were investigated and future prospects in relevant research areas were forecasted.

Background The domestication of tree shrews represents an important advance in the development of standardized laboratory animals. Little is known regarding the miRNA changes that accompany the transformation of wild tree shrews into domestic tree shrews. Results By performing miRNA-seq analysis on wild and domestic tree shrews, we identified 2410 miRNAs and 30 differentially expressed miRNAs in the hippocampus during tree shrew domestication. A KEGG analysis of the differentially expressed genes showed that the differentially expressed miRNAs were associated with ECM-receptor interaction, the phosphatidylinositol signaling system, protein digestion and absorption, inositol phosphate metabolism, lysine degradation, fatty acid degradation and focal adhesion. Most of these pathways could be classified under environmental information processing, organismal systems and metabolism. The miRNAs exclusively expressed in wild and tame tree shrews GO enriched in terms of divergent functions. The miRNA-mRNA networks suggested that novel-m1388-5p and novel-m0746-5p might play regulatory roles in domestication of tree shrews. Real–time RT-PCR analysis was employed to verify the presence of these miRNAs. Conclusion We identified a number of candidate miRNA-regulated domestication genes that may represent targets for selection during the domestication of tree shrews.

In this work, polyoxometalate-modified magnetic nanocomposite Fe3O4@PDA@POM was prepared by coating [Cu(HL)4]2[P2Mo5O23]2·8H2O (POM, L = 2-aminopyridine) on the surface of a preassembled polydopamine (PDA)-capped carboxyl-functionalized Fe3O4 magnetic microspheres. Our studies on Gram negative bacterium Escherichia coli (E. coli) indicated that owing to the collective effect between preassembled Fe3O4 and POM, the Fe3O4@PDA@POM nanocomposite loaded on nickel foam exhibited outstanding antibacterial activity and reusability, and even after 6 cycles it has a high antibacterial capability of ca. 90%. Further extension of this investigation towards Gram positive bacterium Staphylococcus albus (S. aureus) demonstrated a similar toxicity pattern, confirming the potential applications of this material for water treatment in biochemical processes. The antibacterial mechanism of the Fe3O4@PDA@POM nanocomposite was further investigated by taking E. coli as a model microorganism.

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Two-dimensional transition metal dichalcogenides are regarded as the ideal hosts for zinc-ions. Herein, a facile hydrothermal method is proposed to fabricate the metallic phase (1T phase) MoS2/multi-walled carbon nanotube (MWCNT) hybrids serving as the cathode materials for zinc-ion batteries (ZIBs). By virtue of the exertion of phase engineering and the synergy between the 1T MoS2 nanosheets and MWCNT framework, the transfer kinetics of zinc-ions of the prepared hybrid are remarkably accelerated, leading to boosted electrochemical properties at both room temperature and low temperatures. The hybrid electrode delivers a high reversible capacity of 161.5 mAh g−1 after 100 cycles at 0.1 A g−1, and good cycling stability with a desired capacity retention of 84.6% over 500 cycles at 1 A g−1. Furthermore, its boosted capability of zinc-ion storage in a low-temperature atmosphere is revealed. This work not only provides an effective way to squeeze the values of phase engineering of MoS2 in ZIBs, but also reveals the great potential of MoS2-based composites in low-temperature energy storage devices.

Currently, substantial interest is focused on developing assisted tandem catalysis to optimize the reaction conditions for each step in the process. By combining a molybdate oxidation catalyst and alkaline μ3-OH tricopper (II) cores into a metal-organic framework (MOF), a bifunctional catalyst, Cu3(μ3-OH)2(4,4′-BPY)(MoO4)2 (CuMo-BPY, BPY = 4,4′-bipyridine), was achieved and successfully explored for the assisted tandem catalytic conversion of olefins into value-added cyclic carbonates. CuMo-BPY displayed a three-dimensional (3D) extended network of two-dimensional (2D) inorganic CuMo layers interconnected with 4,4′-bipyridine groups. Two potential catalytic sites, Mo(VI) oxide (an oxidant for the epoxidation of olefins) and the alkaline μ3-OH of tricopper (II) cores (for the capture and activation of CO2), exhibit an orderly distribution and spatial matching in the framework, which can provide further compatibility with the Mo=Ot-activated epoxidation intermediate to drive tandem catalysis in a single workup stage.

In this paper, three bismuth(III) and diorganotin(IV) complexes based on bis(2-acetylpyridine) thiocarbonohydrazone (H2L) have been fully designed. The tests of the complexes on inhibiting human hepatocellular carcinoma HepG2 cells growth in vitro revealed that the complexes have higher activity against HepG2 cells but much less toxicity toward normal hepatocyte QSG7701 cells. Particularly, 1 exhibited higher activity with a lower IC50 value (compound concentration that produces 50% of cell death, 3.42 ± 0.25 µM). Moreover, cytotoxicity experiments involving with mitochondria confirmed that 1 restrained cells growth in a dose-dependent manner. Protein analysis indicated that 1 restrained Bcl-2 expression and accelerated Bax expression, inducing caspase-3 activation.

A new Strandberg-type polyoxometalate compound [Co(L)2(H2O)2]2H2[P2Mo5O23]·2H2O (1), (L = pyridine-2-carboxamide) has been synthesized and structurally characterized by elemental analysis, spectroscopic methods (IR, UV-Vis) and X-ray powder diffraction (XRD), as well as single crystal X-ray diffraction. Compound 1 consists of one [P2Mo5O23]6–, two [Co(L)2(H2O)2]2+ and two dissociative water molecules. Biological studies indicated that compound 1 exhibited effective activities against both HepG2 (human hepatocellular carcinoma) cells and HCT-116 (human colorectal cancer) cells and lower toxicity against normal HL-7702 (human normal hepatocyte) cells. A synergistic effect involving L, metal ions and P2Mo5 cluster could probably explain the improved growth-inhibiting properties.

A new metal-organic framework based on manganous (II) ions and a paddle wheel ligand, H3[Mn3O3(BTB)] (Mn-BTB, HBTB = 1,3,5-tris(4-carboxyphenyl)benzene acid), was synthesized and structurally characterized. Mn-BTB was formed via self-assembly of one-dimensional (1D) helical chains interconnected through the carboxyl groups of the tripodal ligand HBTB to generate a 3D, extended network with a nanotube-like architecture and aperture size of 18.22 A × 16.40 A. The 2-fold self-interpenetration significantly enhanced the stability of the framework, although it minimized the empty space to some extent. Mn-BTB contains an accessible volume of 3143.6 A3 with a 47.1% porosity, which allowed the adsorption of large dye molecules. Cationic dyes (methylene blue (MB) and rhodamine B (RhB)) and an anionic dye (methyl orange (MO)) were examined for selective dye adsorption on Mn-BTB. Mn-BTB with an anionic skeleton was beneficial for the selective adsorption of cationic dyes.

Two cadmium (II) complexes formulated as [Cd(L1)(HL1)]ClO4 (Cd1) and [Cd(L2)2] (Cd2), also two antimony (III) complexes formulated as [Sb(L1)2]2Cl2·CH3OH (Sb1) and [Sb(L2)Cl2] (Sb2) (HL1 = 2-acetylpyrazine N4-methylthiosemicarbazone, HL2 = 2-acetylpyrazine N4-dimethylthiosemicarbazone) have been synthesized, and the molecular structure of the four complexes have been determined by single crystal X-ray diffraction. The antimicrobial study has been conducted against E. coli and S. aureus, and the results indicated that the antibacterial activity of Cd1 and Sb1 increased to some extent than their ligand HL1, while Cd2 and Sb2 presented fairly effective antibacterial activity mainly the same as their ligand HL2. The four compounds all exhibited improved cytotoxic activity against the human hepatocellular carcinoma HepG2 cells than the ligands. While Cd2 displayed the most effective antiproliferative activity, and also the preferable selectivity for HepG2 cells versus normal QSG7701 cells. It is noted that there was a strong relationship between the activity of the ligand HL2 and its cadmium (Ⅱ) or antimony (III) complexes.

Four metal complexes based on 2-benzoylpyridine N,N-dimethylthiosemicarbazone (Bp44mT) were designed. Free ligand and zinc(ii), diorganotin(iv), gallium(iii) and cadmium(ii) complexes all demonstrated pronounced activity, which was indicated using the growth inhibition test in vitro. Interestingly, most of the compounds were found to be selective against hepatocellular carcinoma (HepG2) cells but had little effect on normal hepatocyte (QSG7701) cells. In particular, Zn(Bp44mT)2 (1) exhibited toxicity on QSG7701 cells which approximately 12-fold lower than that on HepG2 cells. The studies of mechanisms of action indicated that 1 induced reactive oxygen species (ROS) generation in a dose-dependent manner via the mitochondria transduction pathway. Protein analyses showed that 1 significantly promoted p21 and p53 gene expression, causing caspase-3 activation.

Three Strandberg-type polyoxometalate compounds [Cu(L)2(H2O)2]2H2[P2Mo5O23]·2CH3OH (1), [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]·4H2O (2), [Cd(L)2(H2O)2]2H2[P2Mo5O23]·2CH3OH (3), (L = pyridine-2-carboxamide) have been synthesized and structurally characterized by elemental analysis, spectroscopic methods (IR and UV–vis) as well as single crystal X-ray diffraction. Single-crystal X-ray structural analyses indicate that 1 and 3 are isostructural and crystallized in monoclinic, space group I2/a. Biological studies have indicated that compounds 1–3 exhibit broad and effective activities against the tested cells. A synergistic effect involving L, metal and P2Mo5 could probably explain the improved growth-inhibiting properties. Both coordination mode and the type of metal ion play significant roles in these compounds cytotoxicity.

Graphene quantum dots (GQDs) with unique and tunable physical properties have been the focus of considerable attention because of their potential for electronic and photonic applications. In this work, the electronic polarizability and second hyperpolarizability of hexagonal GQDs were investigated using density functional theory. The effects of size, substituent, and incident frequency of hexagonal GQDs on their electronic polarizability and second hyperpolarizability were comprehensively examined. Increasing the size of hexagonal GQDs enhanced the electronic polarizability and static second hyperpolarizability. The (hyper)polarizability of hexagonal GQDs was remarkably tuned by introducing electron donor/acceptor groups and incident frequency. This study provides new possibilities for practical applications of graphene materials in the nonlinear optical field.

In this paper, density functional theory method was employed to study the electronic absorption spectrum and electronic static second hyperpolarisability of X-shaped pyrazine derivatives with two-dimensional charge-transfer structures. Computational results show that the push–pull electron abilities of the substituent groups and the length of the conjugated chains affect the electronic spectrum and static second hyperpolarisability of the pyrazine derivatives. As the push–pull electron abilities of the substituent groups or the length of the conjugated chains increases, the frontier molecular orbital energy gap decreases, resulting in increased second hyperpolarisability and redshift of the electronic absorption bands. The electronic absorption spectra of the pyrazine derivatives maintain good transparency in the blue light band. The electronic static second hyperpolarisability exhibits a linear relationship to the frontier molecular orbital energy gap. Particularly, increasing/decreasing the push...

Catalytic asymmetric cascade reactions in which the substrates are transferred through well-choreographed consecutive independent steps by a single catalyst have received increasing interest. By incorporating a chiral organocatalyst pyrrolidine, an oxidation catalyst polyoxometalate and a Lewis acid catalyst copper(II) into a single porous coordination network (PCN), two enantiomorph CuW-PYIs (PYI=pyrrolidine-2-yl-imidazole) with novel Kagome lattice were achieved and applied in the conversion of aldehyde with ketone into value-added chiral epoxy ketones in a one-pot procedure. The chiral pyrrolidine organocatalysts interact with the carbonyl group of ketones throughout the reaction, which is beneficial for achieving compatibility between the reaction intermediates and synergy of the multiple catalytic cycles, thus driving the direct aldol/epoxidation cascade reaction in an orderly and asymmetrical way. Moreover, the “two-center catalysis” principle was well demonstrated in the direct aldol/epoxidation cascade reactions.

Two metal complexes [(Me)2Sn(L)(OAc)] (1), and [Pd(L)Cl] (2) based on 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone have been synthesized and structurally characterized. X-ray crystallography reveals that in title compounds, each thiosemicarbazone adopts tridentate NNS manner to coordinate with the metal center, and the metal coordination geometry can be described as a distorted pentagonal bipyramid in 1 and a contorted square-planar in 2, respectively. Growth inhibition assays have indicated that two compounds can effectively inhibit the growth of HepG2 cancer cell lines at micromolar concentrations. In addition, apoptosis mechanisms of 2 on HepG2 cells were further investigated. The results show that 2 can promote the apoptosis of HepG2 cells and the apoptosis is associated with the activation of caspase-3.

Developing efficient photocatalysts for direct oxidative coupling of alkenes and amines with O2 under mild conditions is very significant. Herein, ZnW-PYI is well-designed by assembling a [PZnW11O39(H2O)]5- photooxidation catalyst and chiral aminocatalyst pyrrolidine-2-ylimidazole (PYI) via a coordination model. ZnW-PYI efficiently catalyzed the synthesis of imines from alkenes and amines using O2 as the oxidant through nucleophilic catalysis by employing pyrrolidine as an organocatalyst. Combining a polyoxometalate and PYI within one single framework is an effective approach not only for stabilization and heterogenization of the redox-active catalyst and aminocatalyst but also for realization of compatibility between the reaction intermediates and synergy of multiple catalytic cycles.

The magnetic adsorbent, Fe3O4@[Ni(HL)2]2H2[P2Mo5O23]&middot, 2H2O (Fe3O4@1), is synthesized by employing the nanoparticles Fe3O4 and polyoxometalate hybrid 1. Zero-field-cooled (ZFC) and field-cooled (FC) curves show that the blocking temperature of Fe3O4@1 was at 120 K. Studies of Fe3O4@1 removing cationic and anionic dyes from water have been explored. The characterization of Fe3O4@1, effects of critical factors such as dosage, the concentration of methylene blue (MB), pH, adsorption kinetics, isotherm, the removal selectivity of substrate and the reusability of Fe3O4@1 were assessed. The magnetic adsorbent displayed an outstanding removal activity for the cationic dye at a broad range of pH. The adsorption kinetics and isotherm models revealed that the adsorption process of Fe3O4@1 was mainly governed via chemisorption. The maximum capacity of Fe3O4@1 adsorbing substance was 41.91 mg g&minus, 1. Furthermore, Fe3O4@1 showed its high stability by remaining for seven runs of the adsorption-desorption process with an effective MB removal rate, and could also be developed as a valuable adsorbent for dyes elimination from aqueous system.

In this article, three organotin complexes formulated as [(Me)2Sn(H2L1)] (1), [(Ph)2Sn(H2L1)]·MeOH (2) and [(Me)2Sn(HL2)(OAc)]4(Me)2O (3) (H4L1 = bis(2-hydroxybenzaldehyde) thiocarbohydrazone and H2L2 = bis(2-acetylpyrazine) thiocarbonohydrazone) have been synthesized and structurally characterized. Growth inhibition assays indicated that both the proligands and the three complexes are capable of showing anticancer activity against the human hepatocellular carcinoma HepG2 cells with H2L2 and complex 3 showing much higher cytotoxic potential. Subsequent toxicity studies on normal QSG7701cells showed that complex 3 has the highest tumor cell selectivity, and its IC50 value on QSG7701 cells is 8.48 fold higher than that in HepG2 cells. In acute toxicity experiments, complex 3 produces a dose-dependent effect in NIH mice with a LD50 value of 17.2 mg kg−1.

In order to perform fast action of actuator, a large flow rate of hydraulic pump is needed. High speed operation of gear pump becomes one of the most effective ways to reach large flow rate of gear pump in a finite volume. However, high speed rotation can easily result in air is absorbed into gear pump, which exacerbating the cavitation of gear pump. In order to study the dynamic evolution of gas phase during the cavitation in gear pump and analyze the coupling relationship between air and other dynamic behavior, this study established a fluid dynamics model of the multi-connected volumes inside gear pump. Meanwhile, we used the method of computational fluid dynamics and the full cavitation theory to simulate the instantaneous state of cavitation in the multi-connected volumes inside gear pump at different rotation speeds and different suction pressure. The results indicated that: at different rotational speeds and different suction pressures, different degrees of cavitation will occur in internal multi-connected volumes of gear pump; with the increase of rotational speed or the decrease of suction pressure, the maximum vapor volume fraction and cavitation degree of flow filed in gear pump will increase; with the cavitation increasing, the flow state of gear pump becomes more and more unstable, which reduces the continuity and stability of gear pump’s outlet flow.

A new hexatungstate compound, [Ni2(L)3]2[W6O19]·2H2O (1) (HL = 2-acetylpyrazine-N(4)-methyl thiosemicarbazone) has been synthesized and characterized by elemental analyses, infrared (IR) spectroscopy, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and UV–Vis spectra. A 3D supramolecular structure of 1 is formed by hydrogen bonding, which exhibits a highly selective adsorption for methylene blue (MB), gentian violet (GV) and fuchsin basic (FB) organic dyes with the efficiencies of 99%, 94% and 94%, respectively. Additionally, the adsorption kinetics demonstrates that the MB removal corresponds to the pseudo-second-order model. The recyclability experiments illustrated that 1 could be reused at least five cycles, revealing a potential ability in the disposal to dye wastewater.

A hydrophilic inorganic porous catalyst was prepared via the hydrothermal method. The combination of [WZn3(H2O)2(ZnW9O34)2]12- and Co(ii) provides a synergistical catalytic way to promote oximation of aldehyde/ketone with in situ generated hydroxylamine that initially produces an oxime, which further either dehydrates into a nitrile or undergoes a Beckmann rearrangement to form an amide.

Multifunctional [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]·4H2O/Fe3O4 (HL = pyridine-2-carboxamide) nanocomposites were successfully synthesized by combining [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]·4H2O and Fe3O4 nanoparticles. The characterization was performed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), X-ray powder diffraction (XRD) and ultraviolet-visible light absorbance spectrometry (UV-vis). The XRD and TEM analyses reveal that the nanocomposites possess high crystallinity with an average particle size of ∼19.43 nm. The VSM and UV-vis demonstrate excellent superparamagnetic behavior and two well-behaved absorption bands of the nanocomposites. The adsorption activity of the nanocomposites was investigated using methylene blue, gentian violet, safranine T, fuchsin basic, methyl orange and Sudan red (III) as probe molecules, and the results reveal that the [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]·4H2O/Fe3O4 nanocomposites have selective adsorption behavior for organic dyes. The recycling performance was observed using basic fuchsin, and the results demonstrate that the nanocomposites exhibit good recyclability and high stability. The [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]·4H2O/Fe3O4 nanocomposites have a promising future for magnetic, optical and biomedical applications.

In this paper, synthesis and characterization of metal complexes [Cu2(L)3]ClO4 (1), [Ga(L)2]NO3·2H2O (2) and [In(L)2]NO3·H2O (3) (HL = 2-acetylpyridine N(4)-phenylthiosemicarbazone) was carried out, including elemental analysis, spectral analysis (IR, UV-vis, NMR), and X-ray crystallography. Complex 1 contains one S-bridged binuclear [Cu2(L)3]+ unit, where two Cu atoms display diverse coordination geometries: one being square planar geometry and the other octahedral geometry. Both 2 and 3 are mononuclear complexes, and the metal centers in 2 and 3 are chelated by two NNS tridentate ligands possessing a distorted octahedral geometry. Biological studies show that all the complexes possess a wide spectrum of modest to effective antibacterial activities and remarkable cytotoxicities against HepG2 cells, and 1, in particular, with an IC50 value of 0.19 ± 0.06 μM, is 113-fold and 28-fold more cytotoxic than HL and the antitumor drug mitoxantrone, respectively. In addition, 3 exhibits excellent photoluminescence properties. Upon the addition of 1 equiv of In3+ ions, a remarkable fluorescence intensity of HL and fluorescent color change (from transparent to light-green) could be observed with 365 nm light, indicating that this ligand may be used as a promising colorimetric and fluorescent probe for In3+ detection.

Two hybrids, [Ru(bpy)2(CH3CN)2]2[W10O32]·2CH3CN (RuW-1) and [Ru(bpy)3]2[W10O32] (RuW-2) (bpy = 2,2′-bipyridine), were synthesized by the reaction of (2,2′-dipyridyl)ruthenium complexes and decatungstate, under hydrothermal conditions, and characterized by IR, UV, fluorescence and transient absorption spectroscopy. The influences of the coordination environment of the centre ion, Ru(II), are compared and discussed in detail on the basis of analyzing their photophysical and photochemical properties. Kinetics experiments for the photodegradation of Rhodamine B (RhB) dye were followed with spectrophotometric analysis showing an absorbance decrease at 544 nm resulting from the cleavage of the aromatic ring of RhB. UV spectroscopy indicated that the degradation proceeds with a pseudo-first-order rate constant in the range of 10−3 to 10−2 s−1. These results demonstrate that the hybrids have effective activity and reusability for the photodegradation of RhB.

Two metal complexes [Cd(L) 2 ]·0.275H 2 O( 1 ) and [In(L) 2 ]NO 3 ( 2 ) (HL = 2-benzoylpyridine N (4)-cyclohexylthiosemicarbazone) have been synthesized and structurally characterized by elemental analysis, a number of spectroscopic methods (IR, UV-vis, NMR), mass spectrometry, and X-ray crystallography. The Schiff’s base ligand forms hexacoordinated complexes having octahedral geometry for Cd(II) and In(III) complexes, respectively. The synthesized compounds were tested for antiproliferative activity and showed the ability to kill HepG2 cells (human hepato cellular carcinoma) significantly, especially 2 with IC 50 = 2.02 ± 0.14 μM. Of particular note is the fact that complex 1 has ca 12-fold lower toxicity in the normal hepatocyte QSG7701 cells than in the hepatocellular carcinoma HepG2 cells. In addition, complex 2 also exhibited excellent luminescent property. Upon the addition of 1 equiv of In 3+ ion, 200-fold fluorescence enhancement of HL at λ em = 504 nm has been observed. Moreover, the fluorescent color change (from transparent to light-green) could be observed by naked eyes under the light of 365 nm. These findings can expand the applications of thiosemicarbazone derivatives in the fields of colorimetric and fluorescent probes.

In this article, two nickel complexes of 2-acetylpyrazine thiosemicarbazone formulated as [Ni(L1)2]·CH3OH (1) and [Ni2(L2)3]ClO4·C2H5OH (2) (HL1 = 2-acetylpyrazine N4-methylthiosemicarbazone, HL2 = 2-acetylpyrazine N4-dimethylthiosemicarbazone), have been synthesized and structurally characterized. The antibacterial activities of the two complexes and ligands were studied. It is found that the ligand HL2 and its corresponding complex displayed effective antimicrobial activity against the tested bacterial. Besides, the growth inhibition assays indicated that complex 2 and the two proligands are capable of showing inhibitory activity against the human hepatocellular carcinoma HepG2 cells, and the subsequent toxicity study on normal QSG7701cells showed that complex 2 has the highest tumor cells selectivity, and its IC50 values is 7.21 times higher than in HepG2 cells.

Developing a highly effective process for synthesis a cyano-bridged compound to avoid toxic organic or inorganic cyanides is very significant method for alleviating cyanides pollution. Here, a CN-based MOF catalyst (Cu(I)–CN–BPY) was synthesized by using copper ions coupled with Na4W10O32 in CH3CN under solvothermal conditions. The cyano-groups are generated in situ from the cleavage of C(sp3)–C(sp) in CH3CN. Because Cu(I) sites have ability to activate π-activate internal alkynes of carbon–carbon triple bonds for carboxylic cyclization reactions, which was applied in the cyclization of propargylic alcohols with CO2 and exhibited high efficiency with >95 % yields. For seeking out the active sites of MOF structure in carboxylic cyclization, we also synthesized two MOFs of Cu(I)–Cl–BPY and Cu(I)–I–BPY, and investigated for this reaction.

In this article, two Keggin-type polyoxometalates [Co(L)2]3[PMo12O40] (1) and [Co(L)2]3[PW12O40] (2) (HL = 2-acetylpyrazine thiosemicarbazone) were prepared and fully characterized. The compounds are stable in aqueous solution with different pH values and show superior antibacterial activity against Escherichia coli (E. coli: minimal inhibitory concentration (MIC) = 0.00375, 0.12 μg/mL), Agrobacterium tumefaciens (A. tumefaciens: MIC = 0.06, 0.12 μg/mL), Bacillus subtilis (B. subtilis: MIC = 0.015, 0.06 μg/mL) and especially for Staphylococcus aureus (S. aureus: MIC = 0.00048, 0.015 μg/mL) for 1 and 2, respectively. The time kill studies showed the entire killing of specific bacteria during 4 to 8 h. In addition, the possible antibacterial mechanism of compound 1 was explored systematically. The experimental results proved that cell wall/membrane damage, leakage of protein, inhibition of respiratory chain dehydrogenases activity, enhancement of intracellular reactive oxygen species (ROS) and depletion of glutathione (GSH) were the potential causes of bacteria death.

A metal-organic framework, Cd−TIPA, was synthesized using cadmium ion and a stretched triangular rigid N-containing ligand tris-(4-imidazolylphenyl)amine (TIPA) as a strong electron donor. Cd−TIPA features an unusual 3D structure of two sets of layers linked in an interpenetration arrangement, resulting in framework with 26.1% porosity. Cd−TIPA possesses a long luminescence lifetime of 5.76 μs and Mott−Schottky measurements indicate Cd−TIPA is a representative n-type semiconductor. Cd−TIPA features a potential of the conduction band (LUMO) level (−1.30 V vs. NHE), which is more negative than that of Cr2O72−/Cr3+, thus providing the theoretical possibility of reduction. The valence band (HOMO) level is estimated as 1.37 V based on a Tauc plot, indicating a higher oxidation ability for H2O. The observable quenching effect of Cr2O72− anions on the emission of a suspension of Cd−TIPA indicates the efficient electron transfer. As expected, Cd−TIPA functioned as an efficient catalyst for heterogeneous photocatalytic reduction of Cr2O72− with high catalytic efficiency (93%) in 12 min.

The reaction of diorganotin(IV) with ligands (HL1 = 3-aminopyridine-2-carbaldehyde N(4) methylthiosemicarbazone, HL2 = 3-aminopyridine-2-carbaldehyde N(4)-dimethylthiosemicarbazone) afforded two compounds [PhSn(L1)Cl2] (1) and [(Ph)2Sn(L2)Cl] (2), respectively. The compounds were characterized by elemental analysis, infrared spectrum, UV–vis spectrometry, and X-ray crystallography. The ligands and corresponding complexes were assayed for their in vitro pharmaceutical activity against different pathogenic strains of bacteria by disk diffusion method. The results demonstrate that 1–2 have remarkable antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). 1 exhibit higher antibacterial properties against S. aurenu (MIC = 0.00095 μg/mL) and E. coil (MIC = 0.0019 μg/mL). In the same experimental conditions, the two complexes display more potent activity relative to standard antibiotics Kanamycin and Ampicillin.

Up to now, main group gallium(III) complexes with thiosemicarbazones have been comparatively rare. Here, a main group six-coordinated gallium(III) complex [Ga(L)2]NO3·H2O (1) (HL = 2-acetylpyrazine N4-phenylthiosemicarbazone) has been synthesized and characterized by elemental analysis, IR and UV/Vis spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The cytotoxicity data suggest that 1 exhibits significant antiproliferative activity in vitro against three human cancer cells. Its possible apoptotic mechanism has been evaluated in HepG2 cells. 1 induces a dose-dependent apoptosis in HepG2 cells and the apoptosis is associated with reduction of mitochondrial membrane potential.

A 2-thiophene N(4)-phenylthiosemicarbazone ( HL ) ligand and its three metal derivatives [CuL 2 ] ( 1 ), [NiL 2 ] ( 2 ) and [PdL 2 ] ( 3 ) are synthesized and characterized by elemental analysis, IR spectra, mass spectra as well as the single-crystal X-ray diffraction. Compounds 1 – 3 have the identical architectures in which the Schiff bases L − ions act as the bibasic chelating ligands with thiolate S and imine N atoms as the donor sites. Cytotoxic studies carried out in vitro against human liver hepatocellular carcinoma HepG2 cells and human normal hepatocyte QSG7701 cells show that 1 can be able to inhibit cell proliferation growth. Compound 1 promotes a dose-dependent apoptosis in HepG2 cells. The potential structure-activity relationships among HL and 1 – 3 are further investigated by Hirshfeld surface combining fingerprint plots.