甲基吡啶侧链金属化和烷基化反应的研究

甲基吡啶侧链上的氢易于质子化被碱金属所取代,但传统的侧链金属化的方法,其实验操作都比较繁复。前文报道,吡啶与金属钠在乙醚回流中可形成吡啶自由基负离子钠络合物(C_5H_5N~-Na~ ),它是一种有效的金属     

过氧铌杂多配合物位置异构体的合成、表征及催化性能

合成了6种钨硅杂多配合物异构体α、β_i-M₃H₂[SiW₁₁(NbO₂)O₃₉]·H₂O(M=Me₄N⁺(TMA),Bu₄N⁺(TBA),Et₄N⁺(TEA);β_i=β₁,β₂,β₃)。IR光谱、UV光谱、极谱、I^--S₂O₃^2-滴定证明合成的杂多配合物中有NbO₂基存在, ¹⁸³W NMR光谱证明其阴离子具有Keggin结构,催化实验结果表明,合成的化合物对烯烃环氧化反应具有催化活性,且过氧杂多配合物的催化活性高于非过氧杂多配合物,β异构体的催化活性高于α。     

原子荧光光谱法直接测定二甲基二硒

硒位于第六主族,为准金属元素。在自然界中硒的存在形式按其结合形态分为无机硒和有机硒[1,2]。有机硒较无机硒具有更高的生物活性,因此准确测定各种样品中的有机硒具有重要意义。对于挥发性有机硒,一般采用洗脱富集将其与样品基体分离,采用固相吸附[3,4]或液氮冷阱捕集[5,6],热解析或溶剂萃取后用气相色谱测定[7,8]。这些方法可以提供许多有机硒的信息,但其不足之处是程序较为繁琐。原子荧光光谱分析法(AFS)具有准确度高、灵敏度高、线性范围宽、干扰少等优点,故本文利用AFS的特点及二甲基二硒(DMDSe)的挥发性,在不加任何试剂的条件下,…     

Analysis of 17β-Estadiol from Sewage in Coastal Marine by Surface Plasmon Resonance Technique

In this study, surface plasmon resonance （SPR） for monitoring 17β-eatradiol （E2） was developed. The small molecule E2 was immobilized on a CM5 sensor chip for an indirect competitive immunoassay to detect E2. The SPR response bahed on the antigen-antibody reaction was measured by injecting the sample solution into the flow system. The limitation of detection was 0.445 μg/L. The developed SPE-SPR system was applied to analyze the seawater samples. Recovery of E2 was 91.6%-93. 1%. Relative standard deviations（RSD） for the E2 assay were between 10.9%-15.1% （n = 3）. The range of determination of E2 samples from the sewage in the coastal marine environ-ment was between ND（lower than detection limit） and ca. 11.78 ng/L.     

酸性沸石分子筛催化Knoevenagel缩合反应

 在高硅／铝比的酸性沸石分子筛HY上实现了Knoevenagel缩合反应．Bronsted酸和Lewis酸均可催化Knoevenagel缩合反应．考察了羰基化合物和活泼亚甲基化合物的反应活性顺序．结果表明，羰基化合物的羰基极化程度越高，反应越容易进行；不同于碱催化时的Knoevenagel缩合反应，活泼亚甲基化合物的活泼氢的酸性并不是影响其反应活性的重要因素．     

合成3,3''''-二吲哚基苯基甲烷的新方法

以无水乙醚为溶剂,室温下无水三氯化铝催化N-(2-氯乙基)苯甲醛亚胺与吲哚反应,合成了3,3'-二吲哚基苯基甲烷和6,12-二苯基吲哚[2,3-b]咔唑,其结构经1H NMR,IR和MS表征.     

固相微萃取-气相色谱联用技术分析混合气体中微量氢

制备钯-5A分子筛萃取头,使用固相微萃取-气相色谱联用技术,建立了对混合气体中微量氢气的分析方法.实验结果表明,含氢浓度在0.0011~0.1250 mL/L范围内,具有良好线性关系,检出限为9×10-4mL/L.此方法和气相色谱法比较,有更高的灵敏度和更少的干扰,2种方法的标准偏差为8.7%.     

钴镍取代杂多酸盐甘氨酸超分子化合物的合成及性质

Supermolecular compounds of glycine monosubstituted heteropolytungstates isomer with Keggin structure β_i-K_6-n(HGly)_n[SiW₁₁M(H₂O)O₃₉]·xH₂O (M=Co²⁺, Ni²⁺； β_i=β₂, β₃) were synthesized and characterized by means of elementary analysis, IR, UV, TG-DTA, X-ray diffraction, polarography and CV. The results indicate that glycin combines the electrostatic effect with heteropolytungstates isomer. The heteropoly anion still remains its Keggin structure in supermolecular compounds. The electrochemical behavior of the compound in 1 mol·L^-1 HAc-NaAc shows that two redox waves correspond to two two-electron processes attributing to the reduction of [SiW₁₁Co(H₂O)O₃₉]^6-. Steady-state fluorescence spectrum shows two intenser fluorescence emission peaks in 447 nm and 486 nm appeared after the supermolecular compound being excited by the excitation wavelength in 274 nm.     

Evolution of Er^3＋ Distribution in the Oxyfluoride Glass Ceramics with Heating

The distribution characteristics of Er3+ ions doped in the oxyfluoride glass ceramics containing LaF3 nanocrystals heat-treated at 650 ℃ for different durations were investigated. The results of the integral absorption cross-section analysis demonstrated that the partition fraction of Er3+ in LaF3 nanocrystals increases with prolonging of heating time. The anomalous phenomena of Er3+ emissions in the up-and the down-conversion fluorescence spectra are well explained based on the calculated results.