Reaction of 1,3-disubstituted isobenzofurans (IBFs) with selenium dioxide in tetrahydrofuran (THF) at room temperature led to the formation of 1,2-diaroyl/(heteroaroyl)benzenes in good to excellent yields. 相似文献
Many reactions show much faster kinetics in microdroplets than in the bulk phase. Most reported reactions in microdroplets mirror the products found in bulk reactions. However, the unique environment of microdroplets allows different chemistry to occur. In this work, we present the first chemoselective N-alkylation of indoles in aqueous microdroplets via a three-component Mannich-type reaction without using any catalyst. In sharp contrast, bulk reactions using the same reagents with a catalyst yield exclusively C-alkylation products. The N-alkylation yield is moderate in microdroplets, up to 53 %. We extended the scope of the microdroplet reaction and obtained a series of new functionalized indole aminals, which are likely to have biological activities. This work clearly indicates that microdroplet reactions can show reactivity quite different from that of bulk-phase reactions, which holds great potential for developing novel reactivities in microdroplets. 相似文献
The effect of thickness of oxide-sensing electrode (SE) on NO2 sensitivity of the planar sensor based on yttria-stabilized zirconia (YSZ) was examined at high temperatures. The sensitivity
of the sensor increased with decreasing thickness of SE, and the highest sensitivity was obtained by using the thinnest layer
of Cr2O3–SE (2.7 μm) at 700 °C. In the case of NiO–SE, the highest sensitivity was observed for the sensor using the 4-μm-thick SE
even at a high temperature of 850 °C. Based on the results of the measurements for the complex impedances, the polarization
curves, and the gas-phase NO2 decomposition catalysis, it was confirmed that the catalytic activity to the gas-phase NO2 decomposition on the oxide–SE matrix played an important role in determining the NO2 sensitivity of the present sensors. 相似文献
To study the surface‐adsorbate properties of ZnO nanowires, a hydrothermal method was modified to grow ZnO nanowires directly on ZnSe, which were then characterized by attenuated total reflection infrared (ATR‐IR) spectroscopy. To prepare ZnO nanowires directly on ATR sensing element of ZnSe, ZnO seed layers were first formed by annealing of ZnO seeds on ZnSe surfaces. The ZnO seed layers then were exposed to growth solution, forming ZnO nanowires directly on the ATR crystals. The interaction properties of the resulting surfaces were studied by an ATR‐IR method. The diameter, length and distribution of the ZnO nanowires can be tuned by adjusting the growth conditions, particularly the growing time and the concentrations of reagents. Two surfaces, namely Zn‐rich and Zn‐O ion‐pair surfaces were studied in detail for their adsorption properties toward compounds bearing different functional groups. By examination of several volatile organic compounds (VOCs), it was found that the Zn‐rich surface is less selective and interacts with compounds bearing the functional groups of amino and hydroxyl. The Zn‐O ion‐pair surface is more selective and a much stronger interaction was observed with non‐aromatic amino compounds. These results indicate that the improving of the selectivity of a ZnO‐based sensing device can be achieved by tuning the surface structure of the ZnO nanomaterials. 相似文献
Green synthesis of functionalized gold nanoparticles has been considered to be more biocompatible and has gained much attention in recent years. The eco‐friendly synthesis, long half‐life of drugs, low cost, and nontoxicity make them an appealing potential option for the biomedical field. The leaf aqueous extract of 10 different plants, namely, Araucaria heterophylla (Ah), Lagerstroemia indica (Li), Combretum indicum (Ci), Melia azedarach (Ma), Muntingia calabura (Mc), Hygrophila auriculata (Ha), Rivina humilis (Rh), Callistemon lanceolatus (Cl), Pterygota alata (Pa), and Vateria indica (Vi) was used for the synthesis of gold nanoparticles (AuNPs). Among them, six plants supported the synthesis of stable AuNPs. The generation of ruby red from pale yellow color proved AuNPs synthesis and which was further confirmed by the absorption peak in UV–Vis spectroscopy. Enhanced antioxidant activity was found with Pa–AuNPs compared with other phytosynthesized AuNPs. Pa–AuNPs were thus characterized by HR‐TEM, EDX, XRD, and FTIR. Pa–AuNPs exhibited potent dose‐dependent anticancer efficacy and an effective dose of IC50 mediated apoptosis and necrosis in MCF‐7 breast cancer cells. Pa–AuNPs significantly enhanced the generation of ROS, in effect inducing mitochondrial membrane sensitization to trigger the cascade of apoptosis. The research highlights the effectiveness of AuNPs on cancer cells in vitro and, in turn, a progressive step toward novel biomedical applications. These findings indicate that phytosynthesized AuNPs may be an enticing anti‐cancer strategy for breast cancer without eliciting toxicity to normal cells. 相似文献
Cobalt chromium-layered double hydroxides (CoCr-LDHs) were electrodeposited on to carbon paper by potentiostatic method from the respective cobalt and chromium ion sources. The electrodeposited CoCr-LDHs were characterized by x-ray diffraction (XRD), Fourier transferred infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), energy-dispersive x-ray analysis (EDX) and x-ray fluorescence (XRF) elemental mapping. The XRD and IR data confirmed that the deposits were CoCr-LDH with carbonate and nitrate ions in the basal space. The SEM observations confirmed that the CoCr-LDH surface had distinct morphology consisting of aggregate size of about 100 nm. For the first time, the supercapacitor characteristics of the CoCr-LDHs were assessed in three-electrode configuration in 1 M KOH or two-electrode (asymmetric capacitor device with reduced graphene-oxide (RGO)). It turned out that the asymmetric capacitor consisted of the CoCr-LDH and the RGO exhibited higher energy density with excellent power density. The higher energy density and power density of the asymmetric capacitor device is believed to be due to the unique LDH morphology in addition to the Faradaic and non-Faradaic contributions. It was demonstrated that the two asymmetric capacitor devices connected in series could light an LED bulb.
The conformationally rigid chiral ligand, trans-12-(pyridin-2-yl)-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid ethyl ester, 1, was designed and synthesized in racemic form. Both isomers were successfully obtained in enantiomerically pure form through classical resolution using l-(+)-tartaric acid in acetonitrile. The nature of the diastereomeric complex formed in this resolution was elucidated using single crystal X-ray crystallographic studies. The absolute configuration of (+)-1 was unambiguously assigned as (11S,12S) by single crystal structural analysis of salt 5 formed from (+)-1 and l-(+)-tartaric acid. 相似文献
Journal of Thermal Analysis and Calorimetry - Owing to the fast depletion of fossil fuels and their skyrocketing price due to the tremendous demand, they become imperative to find renewable... 相似文献