二硫化钼润滑失效的单电子转移机理研究

ＭｏＳ２是一种性能优良的固体润滑剂，为了考察它的润滑失效机理，在给定的试验条件下，对其在不同温度大气环境中的氧化状态与活性作了顺磁共振和Ｘ射线光电子能谱分析研究．在Ｍｏ混合氧化物的Ｍｏ３ｄ包络峰中解叠出２组峰，分别归属Ｍｏ６＋，Ｍｏ５＋和Ｍｏ４＋这３种化学状态，Ｍｏ５＋在４ｄ轨道上有１个未成对的电子，这是Ｍｏ氧化物中的一种过渡化合状态，具有４ｄ电子构型和顺磁性，可以在从室温到５００℃范围内稳定存在，而且活性较好，在光电离作用下形成Ｍｏ的终态化合物．因此，ＭｏＳ２在摩擦过程中由于周围环境和摩擦热等多种因素的作用，在摩擦表面生成Ｍｏ６＋而失效，这是一种单电子转多过程     

阴离子交换树脂结合近红外漫反射光谱测定碳酸饮料中日落黄

采用强碱性阴离子交换树脂富集饮料中的合成食用色素日落黄,用近红外漫反射光谱技术直接测定富集有色素的树脂.将34个模拟样品建模,日落黄浓度范围为0.05～1.2g/L.以柠檬黄和亮丽春红5R为干扰,经偏最小二乘回归建模,得到决定系数为0.9883,标准偏差为0.0187的稳健模型.定量预测3种不同市售饮料中的日落黄,回收...     

Redox-switching of intramolecular magnetic interaction through π-conjugation mode change of 1,2-bis(4-dianisylamino)-1,2-bis(3-N-oxylamino)-substituted tetraarylethylene

To develop the redox-switching system of intramolecular magnetic interaction, 1,2-bis[3-(N-tert-butyl-N-oxylamino)phenyl]-1,2-bis[4-{N,N-bis(4-methoxyphenyl)amino}phenyl]ethylene, tetraarylethylene with two nitroxide radical groups at the meta-position, was synthesized, and characterized by the electrochemical method and ESR spectroscopy. Cyclic voltammetry showed the tetraarylethylene core has the lower oxidation potential than the substituted nitroxide radical moiety. ESR spectroscopy in frozen solution revealed that the neutral form shows the fine-structured spectrum characteristic of the spin triplet species, while the dicationic form shows the anisotropic hyperfine-structured spectrum characteristic of the randomly-oriented nitroxide radical, indicating the drastic change of intramolecular magnetic interaction.     

以环糊精为端基或核的大分子

综述了以环糊精为端基的线形大分子和以环糊精为核的星型大分子的合成技术及功能。现有研究表明其合成方法主要以可控/＂活性＂自由基聚合、活性阴离子聚合为主。以环糊精为端基和以环糊精为核的大分子作为一类功能型聚合物,兼具了环糊精分子与聚合物母体的功能及特点,可在一定条件下实现对客体分子的包合,增强生物相容性及高效的基因传递能力...     

Pressure dependence of Curie temperature in a selenazyl radical ferromagnet

The hydrostatic pressure response of T_C of the bisdiselenazolyl radical ferromagnet 1 up to 5 GPa was investigated by AC magnetic susceptibility measurements using a SQUID magnetometer and a miniature diamond anvil cell. It was found that the ambient pressure value of T_C = 17 K could be raised to 21 K at a pressure of 0.9 GPa. The experimental technique is described in detail and the pressure response is compared to that observed in related systems.     

Samarium diiodide induced cyclizations of γ-, δ- and ε-indolyl ketones: reductive coupling, intermolecular trapping, and subsequent transformations of indolines

This comprehensive study describes our results of samarium diiodide induced 5-exo-trig to 8-exo-trig cyclization/alkylation sequences of 3'-acceptor-substituted indolyl ketones. All cyclization precursors were easily prepared by simple N-alkylation or N-acylation of indole derivatives with the corresponding iodo alkanones, acid chlorides, or lactones. After treatment of indolyl ketones with two equivalents of SmI(2), the generated stabilized carbanionic intermediates were trapped with different electrophiles leading to a variety of highly substituted indoline derivatives in good to very good yields. In general, the cyclization products were obtained as single diastereomers bearing a newly generated quaternary center, a common structural motif in various indole alkaloids. The relative configurations of the products were established by NOE experiments and by single-crystal analysis and follow the rules already established. Furthermore, the obtained products were subjected to a series of chemical transformations, such as oxidation, reduction, and metathesis reactions resulting in a range of interesting synthetic building blocks valuable for further applications.     

介质阻挡放电中OH自由基对甲醛脱除的影响

对管线式介质阻挡放电中的甲醛脱除进行了实验研究, 测量了介质阻挡放电产生的OH (A²Σ→X ²Π, 0-0)自由基发射光谱. 研究了在一个大气压下不同放电峰值电压、放电频率、添加氩气和氧气时甲醛脱除率与OH自由基发射光谱强度的变化关系. 实验结果表明: 在氮气含甲醛体系中, 提高放电峰值电压、放电频率和增大氩气含量时, 甲醛脱除率随OH (A²Σ→X ²Π, 0-0)自由基发射光谱强度的增强而提高; 当在氮气含甲醛体系中增大氧气含量时, 甲醛脱除率随OH (A²Σ→X ²Π, 0-0)自由基发射光谱强度的减弱而降低. 在11.5 kV放电峰值电压和9 kHz放电频率下, 氮气含甲醛体系中甲醛脱除率达93.8%.