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981.
982.
An efficient and widely applicable oxidation method of tribromomethyl carbinols in the presence of pyridinium chlorochromate has been developed with excellent yields up to 96%. This method was well applied for the oxidation of a variety of aromatic, aliphatic, and heterocyclic tribromomethyl carbinols. 相似文献
983.
<正>By the reaction of cadmium chloride with a reduced Schiff base ligand (H_2L = N-(4- carboxybenzyl)-glycine), a novel Cd(II) compound [Cd(HL)_2]·4H_2O (1) has been obtained. Single-crystal X-ray diffraction analysis reveals that it crystallizes in orthorhombic, space group Pbcn with a = 13.9788(8), b = 24.4204(14), c = 13.9580(8), V = 4764.8(5)~3, Z = 8, M_r = 600.84, D_c = 1.675 g/cm~3, μ = 0.983 mm~(-1), F(000) = 2448, S = 1.084, R = 0.0806 and wR = 0.1705 (I > 2σ(I)). It displays a 2D two-fold interpenetrating structure. The Cd(II) ions are six-coordinated. The cross-linkage of Cd(II) ions by the bridge of HL anions results in a [Cd(HL)_2] layer. Every two [Cd(HL)_2]_n layers are penetrated with each other, resulting in a two-fold interpenetrating double-layer structure by π-π stacking interactions and hydrogen bonds. Such double-layers are further linked by hydrogen bonds into a supramolecular structure. Photoluminescent investigation shows that compound 1 displays strong emission in the purple region. 相似文献
984.
985.
Xuejiao Tang Haitao Liao Tao Zheng Pan Yin Prof. Jing Cao Assoc. Prof. Xiaoying Zeng Dr. Chao Weng Prof. Ping Shen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(58):14508-14519
Two dithienocyclopentafluorene-based small-molecule acceptors (SMAs) were developed that feature methylene-functionalized conjugated side chains, to study the effect of arylmethylene substitution and its number on structure, optoelectronic properties and device performance. Results showed that two SMAs have better absorption properties and planarity, lower bandgaps and higher LUMOs compared with the control SMA without conjugated side chains. The synthesized SMAs were tested in polymer solar cells for examples of their applicability. This work argues that the introduction of methylene-functionalized conjugated side chains has great potential in tuning molecular structure, optoelectronic properties, device physics and photovoltaic performance of SMAs. 相似文献
986.
Diffraction anomaly corresponds to an energy re-distribution in the reflected and transmitted light beams and in different diffraction orders of a grating, which leads to sharp modulations on the transmission and reflection spectra. In gratings sitting on a transparent substrate, this portion of the energy is actually transferred to channels separated from the reflected and transmitted beams. These channels are based on multiple degenerated diffraction processes at the same wavelength as the diffraction anomaly. The spectroscopic response of these channels is sensitive to the change in the environmental refractive index and can be utilized in sensor devices. 相似文献
987.
A study was conducted on the effect of atmospheric parameters,including temperature,wind speed,and relative humidity,on fine particulate mass concentrations measured in Jiading District of Shanghai,China, during the period from January 2009 to January 2010.A sensitivity analysis was applied to investigate the interaction between atmospheric parameters and particulate mass concentration.The experiment revealed that the concentration of particulates increased with particle size from 0.1 to 1.0μm,and decreased with the increase of particle size from 1.0 to 2.5μm.The effects of atmospheric parameters on fine mass concentrations were significantly particle size-dependent.The PM1.0-2.5 may come from the size increase of smaller particulates after moisture absorption.And the variation of concentrations of PM0.1-1.0 was mainly attributed to the accumulation of PM0.1.The ventilation index and dilution index were calculated on the basis of data collected in December 2009.A correlation analysis indicated that there was a significant relation between these two indexes and the particulate concentration by examining the three particle size ranges,0.0-0.1,0.1-1.0,and 1.0-2.5μm.The Spearman correlation coefficients that related the ventilation index to the concentration for the three particle size ranges were -0.45,-0.56 and -0.47, respectively,while the coefficients that related the dilution index to the concentration were -0.36,-0.42 and -0.45,respectively. 相似文献
988.
989.
Jie Feng Yonglei Chen Yangxia Han Juanjuan Liu Cuiling Ren Xingguo Chen 《Analytica chimica acta》2016
In recent years, extensive researches are focused on the fluorescent carbon nanoparticles (CNPs) due to their excellent photochemical, biocompatible and water-soluble properties. However, these synthesis methods are generally suffered from tedious processes. In this paper, fluorescent carbon nanoparticles are synthesized by a facile, one-pot, low-temperature method with trypsin and dopamine as precursors. The synthesis process avoids any heating operation and organic solvent, which provides a “green” and effective preparation route. The obtained CNPs exhibit excellent water-solubility, salt-tolerance and photostability. Based on the synergistic action of the inner filter effect and static quenching mechanism, the CNPs are exploited as a “turn-off” fluorescence sensor for sensitive and selective detection of Fe3+ ions. The probe shows a wide linear range from 0.1 to 500 μM, with a limit of detection of 30 nM. Furthermore, the as-fabricated fluorescent sensing system is successfully applied to the analysis of Fe3+ in biological samples such as human urine and serum samples with satisfactory recoveries (92.8–113.3%). 相似文献
990.
设计了一个针对高年级本科生的毛细管电泳分离实验,用以研究pH对生物小分子多肽分离的影响。5种多肽包括Bradykinin、[Hyp3]-bradykinin、Angiotensin I、Leucine Enkephalin和[Met5]-Enkaphalin,被用于毛细管电泳的分离实验。研究了毛细管电泳生物分析实验中最重要的2个因素即电渗流和样品吸附随pH的变化以及对于分离的影响。在pH=10的条件下,酸性多肽几乎没有吸附,少量的碱性多肽有吸附。在pH=6的条件下,碱性多肽具有非常强的吸附从而导致非常差的分离效果,在pH=2.3的条件下,5种多肽都能被很好地分离,由于多肽此时都带有正电荷因此几乎没有吸附。而在此pH,电渗流消失。对具有一定分析化学基础理论知识的学生而言,这是一个非常好的生物分析实验,有助于学生充分理解相关环境因素对仪器分析的重要影响。 相似文献