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301.
Studies of the electrochemical behavior of epinephrine at a homocysteine self-assembled electrode 总被引:6,自引:0,他引:6
The self-assembled electrode with the homocysteine monolayer (Hcy/Au) has been characterized by infrared spectroscopy and ac impedance spectroscopy in electrolyte. The Hcy/Au electrode is demonstrated to promote the electrochemical response of epinephrine (E) by cyclic voltammetry. A pair of well-defined redox waves was obtained and the calculated standard rate constant (ks) is 2.1×10−2 cm s−1 at the self-assembled electrode. The reduction peak of E can be used to determine the concentration of E in presence of ascorbic acid (AA) owing to the Hcy/Au also promoting the electrochemical oxidation of AA. 相似文献
302.
303.
The reaction of PdCl2 in water with 2-hydroxypropane-1, 3-diaminetetraacetic acid (HPDTA) gave the complex Pd (C11H16N2O9)·1. 5H2O, which was characterized by elemental analysis, IR, NMR and single-crystal X-ray diffraction. The spectroscopic and X-ray diffraction data show that Pd ( Ⅱ ) is coordinated by two nitrogen atoms and two car-boxylic oxygen atoms. The complex crystallizes in monoclinic space group Pc with a = 1. 1240(2), b=1. 1183(2), c=1. 2597(3) nm, β=96. 33(2)°V=1. 5737(6) nm3, Z = 4, R= 0.038. The structure contains two crystallographically independent molecules which have slightly different orientations and are connected by hydrogen bonds. 相似文献
304.
合成了新的O-(硫杂蒽酮-[2]-基)-氧乙酸及其稀土配合物. 通过元素分析, IR, 1H NMR, UV, DTA-TG和13C NMR谱对其结构进行了表征. 研究表明: 配体羧羰基脱质子后与金属离子配位, 2位氧原子也与金属离子配位, 配合物中含有一定量的配位水, 配合物为非电解质类型. 同时, 研究了O-(硫杂蒽酮-[2]-基)-氧乙酸稀土配合物对质粒DNA的切割作用. 结果表明: 铕的配合物对DNA的切割较明显, 且当配合物浓度增加时, 质粒DNA的超螺旋构型逐渐减少, 而缺刻、开环型构型逐渐增多. 在相同条件下, Eu(III)离子对质粒pBR322DNA几乎没有切割作用; 配体O-(硫杂蒽酮-[2]-基)-氧乙酸对质粒pBR322DNA也有切割作用, 但配合物EuL3对质粒pBR322DNA的切割作用明显强于配体, 表明稀土离子Eu(III)与配体生成配合物后有较好的协同切割作用. 相似文献
305.
CrOx/ SBA-15介孔催化剂上丙烷在二氧化碳气氛中脱氢反应的研究 总被引:2,自引:0,他引:2
The structure and catalytic properties based on Chromium Oxide supported on mesoporous SBA-15 for oxidative dehydrogenation of propane by CO2 have been studied by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and propane pulsing experiments in the absence of gas-phase O2. It has been shown that propane conversion and propene yield increase with Cr loadings. The propane conversion and propene yield on CrOx(Cr: 10wt%)/SBA-15 catalyst for oxidative dehydrogenation of propane by CO2 at 550 ℃ reach 24.8% and 21.8%, respectively .The results of ESR, UV-Vis DRS and propane pulsing experiments indicate that CrⅢ in the CrOx/ SBA-15 catalyst is the main active species in oxidative dehydrogenation of propane by CO2 and CrⅥ, CrⅤ is inactive in dehydrogenation. 相似文献
306.
Three new serratane triterpenoids, (3α,14α,15α,21α)‐3,14,15,21,29‐pentahydroxyserratan‐24‐oic acid ( 1 ), (3α,21β)‐serrat‐14‐ene‐3,21,24,30‐tetraol ( 2 ), and (3α,21α)‐serrat‐14‐ene‐3,21,24,29‐tetraol ( 3 ), were isolated from Phlegmariurus squarrosus, together with eight known compounds. Their chemical structures were elucidated on the basis of in‐depth spectroscopic analyses. 相似文献
307.
Precursor molecule (R)-6,6′-bis(triethoxysilylethen-2-yl)-2,2′-di(methoxyethoxymethyloxy)-1,1′-binaphthyl (R-2) was synthesized by Pd-catalyzed Heck reaction of (R)-6,6′-dibromo-2,2′-di(methoxyethoxymethyloxy)-1,1′-binaphthyl (R-1) intermediate with vinyltriethoxysilane. The hydrolysis and polycondensation of the precursor R-2 produced the corresponding xerogel. Both precursor and xerogel were analysed by NMR, FTIR, UV, CD spectra, fluorescent spectroscopy, polarimetry and elemental analysis. The precursor and xerogel can emit strong blue fluorescence and are expected to have a potential application in the separation of chiral molecules as fluorescent sensor. The precursor exhibits strong Cotton effect in its circular dichroism (CD) spectrum indicating a highly rigid structure. 相似文献
308.
Microscale sample deposition onto hydrophobic target plates for trace level detection of neuropeptides in brain tissue by MALDI-MS 总被引:1,自引:0,他引:1
Wei H Dean SL Parkin MC Nolkrantz K O'Callaghan JP Kennedy RT 《Journal of mass spectrometry : JMS》2005,40(10):1338-1346
A sample preparation method that combines a modified target plate with a nanoscale reversed-phase column (nanocolumn) was developed for detection of neuropeptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A gold-coated MALDI plate was modified with an octadecanethiol (ODT) self-assembled monolayer to create a hydrophobic surface that could concentrate peptide samples into a approximately 200-500-microm diameter spot. The spot sizes generated were comparable to those obtained for a substrate patterned with 200-microm hydrophilic spots on a hydrophobic substrate. The sample spots on the ODT-coated plate were 100-fold smaller than those formed on an unmodified gold plate with a 1-microl sample and generated 10 to 50 times higher mass sensitivity for peptide standards by MALDI-TOF MS. When the sample was deposited on an ODT-modified plate from a nanocolumn, the detection limit for peptides was as low as 20 pM for 5-microl samples corresponding to 80 amol deposited. This technique was used to analyze extracts of microwave-fixed tissue from rat brain striatum. Ninety-eight putative peptides were detected including several that had masses matching neuropeptides expected in this brain region such as substance P, rimorphin, and neurotensin. Twenty-three peptides had masses that matched peaks detected by capillary liquid chromatography with electrospray ionization MS. 相似文献
309.
Hui Chen Yujiao Fan Nian Zhang Sylvain Trpout Bergam Ptissam Annie Brûlet Ben Zhong Tang Min-Hui Li 《Chemical science》2021,12(15):5495
Fluorescent polymer cubosomes and hexosomes with aggregation-induced emission (AIE) were prepared from amphiphilic block copolymers PEG-b-PTPEMA where the hydrophobic block PTPEMA was a polymethacrylate with tetraphenylethene (TPE) as the AIE side group. Four highly asymmetric block copolymers with hydrophilic block weight ratio fPEG ≤ 20% were synthesized. Cubosomes and hexosomes with strong fluorescence emission were obtained by nanoprecipitation of polymers with fPEG < 9% in dioxane/water and THF/water systems. Their ordered internal structures were studied by electron microscopy (cryo-EM, SEM and TEM) and the X-ray scattering technique (SAXS). To elucidate the formation mechanisms of these inverted colloids, other parameters influencing the morphologies, like the water content during self-assembly and the organic solvent composition, were also investigated. This study not only inspires people to design novel building blocks for the preparation of functional cubosomes and hexosomes, but also presents the first AIE fluorescent polymer cubosome and hexosome with potential applications in bio-related fields.Fluorescent Imm cubosome and P6mm hexosome with aggregation-induced emission (AIE) were reported, which were formed by amphiphilic block copolymers PEG-b-PTPEMA. The length of hydrophobic block PTPEMA was adjusted to control morphology formation. 相似文献
310.