芳亚甲基丙二腈、芳亚甲基氰乙酰胺的固相合成

芳醛和丙二腈、氰乙酰胺在NH4Ac催化下经固相反应高产率的得到芳亚甲基丙 二腈和芳亚甲基氰乙酰胺。     

Michael Addition of Thiols to á,(a)-Unsaturated Carbonyl Compounds Catalyzed by Bifunctional Organocatalysts:Asymmetric Michael Addition and Asymmetric Protonation

Recently the hydrogen-bond activated reactions have attracted much attention.1 Takemoto2 reported a highly enantioselective Michael addition of manolate to nitroolefins catalyzed by a bifunctional organocatalyst with tertiary amine and thiourea moiety. As we known,stereoselective conjugate additions of thiols are interesting due to the standpoint of biological and synthetic importance, however, only very limited good results have been obtained except for the works of Shibasaki3, Kanemasa4 and Deng5 et al.In this letter, we report an efficient catalytic asymmetric Michael reactions of thiols to a,a-unsaturated carbonyl compounds promoted by bifunctional organocatalysts. A series of organocatalysts with chiral amine and thiourea structures were designed and synthesized and have been successfully applied in the conjugated additions of thiols to a,a-unsaturated imides and enones.The reactions got quantitative yields and the ee values were up to 84%. It is noteworthy that the a-asymmetric protonation (up to 43% ee) also could be achieved.The Michael addition between aromatic thiols and a,a-unsaturated carbonyl compounds isdescribed as follows:Works to further increase the enantioselectivity is under investigation in our laboratory.     

Diastereoselective Three Component Reaction of N‐Glyoxyloyl Camphorpyrazolidinone,Amine and Allyltributylstannane: Facile Synthesis of Homoallylic Amines

Diastereoselective allylation of imine derived from N‐glyoxyloyl camphorpyrazolidinone and amines was treated with allyltributylstannane in the presence of triflic acid. The corresponding optically enriched homoallylic amines were obtained in reasonable to high material yields and with practical levels of stereoselectivity in 10 min at ambient temperature.     

超声条件下溶胶-凝胶法制备CaSiO_3∶(Pb,Mn)发光材料的研究

采用溶胶-凝胶法并辅以超声技术制备了CaSiO3∶(Pb,Mn)发光材料,对合成物运用荧光光谱、DTA-TG、XRD、FTIR、TEM等手段进行了表征。研究了制备时的物料配比、超声时间及焙烧温度对样品发光强度的影响,找到了最佳的合成条件。结果表明,所得样品其荧光强度约为高温固相法样品的2倍,平均粒径则降低约300 nm。     

Studies on the Spectral Behavior between Protein with Poniacyl Carmine 2B and its Analytical Application

In this paper, the spectral behavior of protein and Poniacyl Carmine 2B (PC 2B) has been studied by spectrophotometric method. The conditional constants, apparent combination constant K and maximum binding number n, were used to express the combination ability of the reactions between PC 2B and protein under a set of given conditions. The Sandell index s was used to express the sensitivity of the determination of protein. The factors, acidity, PC 2B concentration and the ionic strength, were discussed by the change of apparent combination constant and maximum binding number. It was found that acidity of the solution, PC 2B concentration and ionic strength had a significant effect on the sensitivity of the assay of protein. Under the optimal conditions, the apparent combination constant K and the maximum binding number n were 2.36 × 10⁶ L mol^?1 and 95, respectively. With further investigation, it was found that the Scatchard model was suitable in treating the data obtained in the experiments. In the buffer medium of HCl‐KCl at 1.87, the addition of protein made the maximum absorption of the system move from 527 nm to 513 nm. Its apparent molar absorptivity is 4.46 × 10⁵ Lmol^?1 cm^?1 at 513 nm. Beer's law is obeyed in the range of 0 ? 55 μg mL^?1. The system developed in this paper has been used for the determination of protein in milk powder successfully.     

Synthesis of Imidazo[2,1‐a]isoquinolines from α‐Tosyloxyketones and 1‐Aminoisoquinoline in Ionic Liquid Solvent

The room temperature ionic liquid n‐butylpyridinium tetrafluoroborate (BPyBF₄) is used as a ‘green’ recyclable alternative to classical molecular solvents for the cyclocondensation of α‐tosyloxyketones with 1‐aminoisoquinoline to prepare imidazo[2,1‐a]isoquinolines in good yields.     

Interparticle interactions in agglomerates of alpha-Fe2O3 nanoparticles: influence of grinding

We have chemically prepared a sample of antiferromagnetic alpha-Fe2O3 nanoparticles by a gel-sol technique. M?ssbauer spectra of the as-prepared sample showed that superparamagnetic relaxation was suppressed due to strong magnetic interparticle interactions even at room temperature. However, subsequent grinding of the sample by hand in a mortar for some minutes resulted in fast superparamagnetic relaxation of some of the particles. The effect was even more dramatic if the alpha-Fe2O3 powder was ground for a longer time or together with nonmagnetic eta-Al2O3 nanoparticles. Similar effects were found after low-energy ball milling. Thus it is found that the agglomeration of the nanoparticles during preparation under wet conditions results in strong magnetic interparticle interaction, but a relatively gentle mechanical treatment is sufficient to break up the agglomerates, resulting in much weaker interactions. We show that these effects can also be seen when a soil sample containing magnetic nanoparticles is ground.     

多壁碳纳米管负载铂的甲苯加氢脱芳催化剂

以多壁碳纳米管(CNTs)为载体制备了负载型Pt催化剂Pt/CNTs并将其用于催化甲苯加氢脱芳(HDA)反应.结果表明,在1.0%Pt/CNTs催化剂上,在0.4MPa,373K,PhCH3/H2摩尔比=6/94和GHSV=120L/(h.g)的反应条件下,甲苯转化率可达100%,比反应速率为0.0523mmol/(s.m2),分别是γ-Al2O3和AC负载各自最佳Pt负载量催化剂1.4%Pt/γ-Al2O3和2.4%Pt/AC上相应值的1.17和1.18倍.甲苯加氢产物全部为甲基环己烷,其他可能的加氢产物均在气相色谱检测限以下.催化剂的表征研究揭示,用CNTs代替γ-Al2O3或AC作为载体并不会引起所负载Pt催化剂上甲苯HDA反应的表观活化能发生明显变化.与γ-Al2O3或AC负载的相应催化剂相比,一方面,CNTs负载的Pt催化剂易于在较低温度下还原活化,并且其工作态催化剂表面催化活性Pt物种(Pt0)所占表面Pt摩尔分率有所提高;另一方面,CNTs负载的Pt催化剂对H2具有较高的吸附/活化和储存能力.这些促进效应对催化剂HDA活性的提高都有重要贡献.     

CdSe/ZnS-labeled carboxymethyl chitosan as a bioprobe for live cell imaging

A simple and convenient method for the construction of CdSe/ZnS-labeled polysaccharides as bioprobes were developed, which are highly biocompatible and photostable, and have been proven to be suitable for live cell imaging.     

分数导数结合傅里叶最小二乘拟合处理含噪音的重迭信号

提出了一种含噪音重迭信号的综合处理方法 :先用傅里叶最小二乘法拟合噪音数据 ,然后对拟合后的信号求 2 .5次导数 ,在对模拟数据研究的基础上 ,讨论了求导后峰位漂移及其影响因素 ,给出了一个用于矫正峰位值的经验公式。用该方法对模拟和实际的紫外含噪音重迭信号进行处理 ,结果良好