Stereoselective rearrangement of indenobenzazepine cis ketols and with TPAA in pyridine produces spirobenzylisoquinolines and , respectively. The latter product is also obtained by rearrangement of trans ketol . The transformation of ketols and must, therefore, proceed through the intermediacy of aziridinium cation . A similar process obtains in the transformation of to . NaBH4 reduction of gives (±)-raddeanine (). Rearrangement of diol supplies directly. (±)-Yenhusomine () is obtained from the reamangement of either diol, or . In like fashion, diols and supply spirobenzylisoquinoline . 相似文献
In this letter, we report on the fluorescence lifetime imaging and accompanying photoluminescence properties of a chemical vapour deposition (CVD) grown atomically thin material, MoS2. µ‐Raman, µ‐photoluminescence (PL) and fluorescence lifetime imaging microscopy (FLIM) are utilized to probe the fluorescence lifetime and photoluminescence properties of individual flakes of MoS2 films. Usage of these three techniques allows identification of the grown layers, grain boundaries, structural defects and their relative effects on the PL and fluorescence lifetime spectra. Our investigation on individual monolayer flakes reveals a clear increase of the fluorescence lifetime from 0.3 ns to 0.45 ns at the edges with respect to interior region. On the other hand, investigation of the film layer reveals quenching of PL intensity and lifetime at the grain boundaries. These results could be important for applications where the activity of edges is important such as in photocatalytic water splitting. Finally, it has been demonstrated that PL mapping and FLIM are viable techniques for the investigation of the grain‐boundaries.
In this work, we aimed to synthesize and characterize a novel tetra-directional ligand, (2E,2′E)-2,2′-((((2-(1,3-bis(4-((E)-(2-carbamothioylhydrazono)methyl)phenoxy)propan-2-ylidene)propane-1,3-diyl)bis(oxy))bis(4,1-phenylene))bis(methanylylidene))bis(hydrazinecarbothioamide) (5), including thiosemicarbazone group and its novel tetra-directional-tetra-nuclear Schiff base complexes. For this purpose, we used 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) as starting material. 4,4′-((2-(1,3-Bis(4-formylphenoxy)propan-2-ylidene)propane-1,3-diyl) bis(oxy))dibenzaldehyde (3) was synthesized by the reaction of an equivalent 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) and 4 equivalents of 4-hydroxybenzaldehyde. Then, compound 5 was synthesized in high yield (86%) by a condensation reaction of compound 3 with thiosemicarbazide (4). Finally, four novel tetra-nuclear Cr(III) or Fe(III) complexes of compound 5 were synthesized. The synthesized compounds were characterized using elemental analyses, 1H NMR, Fourier transform–infrared spectrometry, liquid chromatography–mass spectrometry (ESI+), and thermal analyses. The metal ratios of the prepared complexes were determined using an atomic absorption spectrophotometer. We also investigated their effects on the magnetic behaviors of [salen, salophen, Cr(III)/Fe(III)] capped complexes. The complexes were found to be low-spin distorted octahedral Fe(III) and distorted octahedral Cr(III), all bridged by thiosemicarbazone. 相似文献
We studied the adsorption of Brilliant Yellow (BY) from aqueous solutions onto sepiolite and determined the adsorption equilibrium isotherms. We applied pseudo-first-order and pseudo-second-order kinetic models; the adsorption of BY onto sepiolite was best described by the pseudo-second-order kinetic model. The experimental data obtained at different temperatures were analyzed using various isotherm models; the Koble–Corrigan isotherm model provided the best fits for the BY adsorption data at all temperatures. The thermodynamic parameters of the BY adsorption onto sepiolite indicated that the adsorption process is spontaneous and exothermic in nature. 相似文献
A novel enzymatic electrochemical biosensor (mCuF/PANI-nf/HA/Lacc/GCE) was designed for detection of bisphenol A (BPA). The copper ferrite nanoparticles was obtained by co-precipitation and its surface was modified with -NH2 functional organosilane. Polyaniline nanofibers were also synthesized by cyclic voltammetry and characterized by FTIR, XRD, TGA, SEM and TEM, respectively. Then, it was crosslinked with hyaluronic acid as an immobilization matrix for Laccase to adhere to surface of the modified copper ferrites. Cyclic and differential pulse voltammetries were used to evaluate the electrochemical performances of the biosensor, which has a LOD value of 5.40 nM and a LOQ value of 16.20 nM in the 0.01–7.50 μM linear working range. The biosensor was successfully applied for determination of BPA in seawater, canned water and milk samples with recoveries ranging from 96.0 % and 100.7 %. In addition, accuracy of the voltammetric determination method in the real samples was carried out by HPLC and spike/recovery test. The layer-by-layer surface modification strategy of the designed mCuF/PANI-nf/HA/Lacc/GCE biosensor opens a new perspective on both BPA determination and using biopolymer in the structure of enzymatic electrochemical biosensors. 相似文献
2-D elemental distribution of Ge in silicon oxide substrates with differing implantation doses of between 3 × 1016 cm− 2 and 1.5 × 1017 cm− 2 has been investigated by Laser-Induced Breakdown Spectroscopy (LIBS). Spectral emission intensity has been optimized with respect to time, crater size, ablation depth and laser energy. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-Ray Spectroscopy (EDX) have been utilized to obtain crater depth, morphology and elemental composition of the sample material, respectively. LIBS spectral data revealed the possibility of performing 2-D distribution analysis of Ge atoms in silicon oxide substrate. EDX analysis results confirmed that LIBS is capable to detect Ge atoms at concentrations lower than 0.2% (atomic). LIBS as a fast semi-quantitative analysis method with 50 µm lateral and 800 nm depth resolution has been evaluated. Results illustrate the potential use of LIBS for rapid, on-line assessment of the quality of advanced technology materials during the manufacturing process. 相似文献
The interference effects of some metal cations on the absorbance of Mo during its determination by flame AAS have been investigated,
in air-acetylene flame, at a fuel flow rate of 1.8 L/min. While the interfering ion concentration was changing between 5 and
40 000 mg/L, the Mo concentration was taken as 10, 20 and 40 mg/L. It was shown that even at low concentrations of interfering
ion there was a large suppression of Mo absorbance. No absorbance was observed for Mo in the presence of 50 time higher concentration
of Mg, Ca, Sr, and Ba. These interference effects were suppressed by additions of 0.04% (m/v) sodium diethyldithiocarbamate
(Na-DDTC), 2% (m/v) ammonium chloride, and 0.4% (m/v) sodium hydrogen phosphate. The interference from another group of elements,
Mn, Fe, Al, Cd, Ni, Cr, Co, Cu and Zn, has been also investigated. In the presence of above mentioned metals, except Mn, the
reproducibility of Mo absorption signal was not satisfactory. In the presence of Mn (5–40000 mg/L) the absorbance of Mo decreased
significantly, however, the reproducibility was high. Molybdenum absorbance decreased under the influence of 5000–40000 mg/L
of Fe, Co, Ni, 500–40000 mg/L of Cr. On the other hand, the absorption signal of Mo increased at about 20–40% in the presence
of Zn and Cd. By the addition of 2% NH4Cl the interference of these metals could be eliminated completely for all mass ratios of Mn: Mo and up to Mo: M mass ratio
of 1: 10–1: 100 for the other metals, and reliable absorbance signals of Mo were obtained.
The text was submitted by the authors in English. 相似文献
N-[(4-Fluorophenyl)sulfanyl]phthalimide (C14H8FNO2S, FP ) was synthesized and characterized using X-ray crystallography. It was then investigated via quantum chemical analysis using the density functional theory (DFT) approach, as well as spectrochemically using FT–IR and 1H and 13C NMR spectroscopy, and elemental analysis. The observed and stimulated spectra are in very good agreement for the DFT method. The in vitro antimicrobial activity of FP against three Gram-positive bacteria, three Gram-negative bacteria and two fungi were determined using the serial dilution method, and FP showed the highest antibacterial activity against E. coli, with a MIC of 128 µg ml−1. Druglikeness, ADME (absorption, distribution, metabolism and excretion) and toxicology studies were carried out to theoretically examine the drug properties of FP . 相似文献
The measurements of the L X-ray intensity ratio I(Lα)/I(Lβ), I(Lα)/I(Lγ), I(Lα)/I(Lι), I(Lβ)/I(Lγ) and I(Lι)/I(Lγ) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV γ-rays from a filtered radioisotope 241Am was used, and by the radioactive decay of 160Tb, 160Er, 173Lu, 182Re, 201Tl, 203Pb and 207Bi. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(Lα/Lβ), I(Lα/Lγ), I(Lα/Lι), I(Lβ/Lγ) and I(Lι/Lγ) intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster–Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results. 相似文献