<em>N</em>-Substituted 5-Chloro-6-phenylpyridazin-3(2<em>H</em>)-ones: Synthesis, Insecticidal Activity Against <em>Plutella xylostella </em>(L.) and SAR Study

A series of N-substituted 5-chloro-6-phenylpyridazin-3(2H)-one derivatives were synthesized based on our previous work; all compounds were characterized by spectral data and tested for in vitro insecticidal activity against Plutella xylostella. The results showed that the synthesized pyridazin-3(2H)-one compounds possessed good insecticidal activities, especially the compounds 4b, 4d, and 4h which showed > 90% activity at 100 mg/L. The structure-activity relationships (SAR) for these compounds were also discussed.     

Three new phenolic glucosides from the roots of Rheum palmatum

A novel naphthalene glucoside, rheumone A (1), with an unprecedented skeleton containing a seven-membered lactone, and two new compounds, 1-O-phloroglucinyl-2-O-galloyl-6-O-cinnamoyl-β-D-glucoside (2) and chrysophanol 1-O-β-D-(6'-O-malonyl)glucoside (3), together with three known compounds (4-6) were isolated from the roots of Rheum palmatum. Their structures were elucidated mainly by spectroscopic analysis. These compounds were evaluated in vitro for their cytotoxicities towards human hepatocellular cancer cell lines Bel-7402 and Bel-7402/5Fu, and human gastric carcinoma cell line BGC-823. None of them showed cytotoxicity with IC(50) far beyond 50 μM.     

A label-free thrombin binding aptamer as a probe for highly sensitive and selective detection of lead(II) ions by a resonance Rayleigh scattering method

The binding of lead(II) ions with unusually high affinity to a thrombin binding aptamer resulted in an enhancement of resonance Rayleigh scattering (RRS). A simple, sensitive, and selective assay for the direct determination of trace amounts of Pb(2+) on the basis of RRS has been proposed.     

Giant metal-organic frameworks with bulky scaffolds: from microporous to mesoporous functional materials

New concepts on the design and synthesis of crystalline metal-organic frameworks (MOFs) have made them a subject of considerable interest in the growing field of materials science. By creating larger cavity sizes by a nearly infinite combination of metal nodes and organic linkers, many innovative characteristics of microporous MOFs have been revealed. The primary goal of this perspective article is to highlight the frontiers in the development of giant MOFs that are deliberately constructed from metallated or metal-free bulky scaffolds. Incorporating these types of distinct bulky ligands into giant MOFs may lead to MOFs with a large cavity size, intriguing properties and new framework topology. Emerging applications of these materials in catalysis, adsorption, and sensors are also discussed.     

Solution processed high performance pentacene thin-film transistors

High performance thin-film transistors were fabricated using a new precursor of pentacene through a multiple spin-heat procedure. High quality pentacene thin films can be prepared by this method and hence a FET device can be made in a top-contact configuration. The device exhibited a remarkable field-effect mobility of 0.38 cm(2) V(-1) s(-1) with an on/off ratio of 10(6).     

Highly enantioselective regiodivergent allylic alkylations of MBH carbonates with phthalides

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine-thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S(N)2'-S(N)2' pathway and an addition-elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form.     

The formation of mesoporous TiO2 spheres via a facile chemical process

The mesoporous TiO(2) solid and hollow spheres have been synthesized via a controllable and simple chemical route. Structural characterization indicates that these TiO(2) mesoporous spheres after calcined at 500 degrees C have an obvious mesoporous structure with the diameters of 200-300 nm for solid spheres and 200-500 nm for hollow spheres. The average pore sizes and BET surface areas of the mesoporous TiO(2) solid and hollow spheres are 6.8, 7.0 nm and 162, 90 m(2)/g, respectively. Optical adsorption investigation shows that TiO(2) solid and hollow spheres possess a direct band gap structure with the optical band gap of 3.68 and 3.75 eV, respectively. A possible formation mechanism for TiO(2) solid and hollow spheres is discussed.     

Conformation dependence of electronic structures of poly(ethylene oxide)

The electronic structure of pure poly(ethylene oxide) (PEO) for four different polymeric chain conformations has been studied by Hartree-Fock (HF) and density functional theory (DFT) through the analysis of their valence band photoelectron spectroscopy (VB-PES), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS). It is shown that the valence band of PEO presents specific conformation dependence, which can be used as a fingerprint of the polymeric structures. The calculated spectra have been compared with experimental results for PEO powder.     

Evaluation on bioactivities of triterpenes from Bergenia emeiensis

Bergenia emeiensis is a traditional folk medicine in China. Most studies are focusing on the bioactivity of bergenin, neglecting other compounds. Therefore, in this present work, the antioxidant, antibacterial and anticancer abilities of triterpenes from B. emeiensis rhizomes (TBE) were comprehensively evaluated. The results showed that TBE could well scavenge DPPH with a lower EC50 of 0.29 mg/mL and could improve the cell viability of CHO cells against H₂O₂ induced cell death. Additionally, TBE also enhanced the resistance of C. elegans under thermal stress, exhibiting a strong antioxidant potential in vivo. Moreover, TBE showed a certain antibacterial ability on five kind strains such as Pseudomonas aeruginosa while TBE could not significantly inhibit the growth of plant pathogenic fungi. Furthermore, TBE possessed an excellent suppression ability on the proliferation of cancer cells especially Hela and Hep G2 cells with an IC50 of 41.79 μg/mL and 48.62 μg/mL at 48 h, respectively. After fractionally extracted with petroleum ether, ethyl acetate and ethanol, ethanol phase (EP) contained the most triterpenes, followed by ethyl acetate phase (EAP) and petroleum ether phase (PEP). Besides, EP and EAP exhibited a strong antioxidant capacity and also inhibited the proliferation of Hela and Hep G2 cells with the effect of pro-oxidation by inducing a high level of ROS and decreasing mitochondrial membrane potential, thus causing oxidative stress then inducing cell apoptosis. Therefore, these outcomes indicated the triterpenes from B. emeiensis possessed a strong antioxidant ability and an anticancer effect, thus making B. emeiensis become a promising potential alternative in pharmacological field.