含铈类水滑石的制备及其衍生物催化研究

采用共沉淀水热法制备了镍铝铈三元复合层状氢氧化物.详细探讨了合成体系pH值、Ce/Al比及陈化条件对合成产物物相的影响;通过XRD,ICP,TG-DTA手段研究了合成物物相、组成及热行为.考察了以合成物为前驱体经焙烧后转化为镍铝铈复合金属氧化物在催化消除NO反应中的应用.实验结果表明,合成镍铝铈三元复合层状氢氧化物的适宜条件是:M2 /M3 =2,Ce/Al=0.07～0.75,pH=5.5～6.9,水热处理条件为110℃,5 h;在pH=5.5～6.9条件下,合成原料配比不同,产物物相相同,但组成不同;合成物热稳定性较差,在T=100～400℃之间,层间吸附水及层间平衡阴离子NO3-脱去,转化为复合氧化物,将此氧化物应用于NO消除反应中,表现出高的低温活性,400℃进行反应,NO转化率达95%,N2选择性几乎100%.     

Synthesis and in vivo study of metallofullerene based MRI contrast agent

Gd@C₈₂(OH)₄₀ has been developed as a new generation of MRI contrast agent. But recently, it was found that Gd@C₈₂(OH) _x with a larger number of OH (x>36) would lead to cage break and hence, release of highly toxic Gd ions. We synthesized the more stable Gd@C₈₂(OH) _x with less OH-number, Gd@C₈₂(OH)₁₆, and studied its proton relaxivity and MRI images. The results indicate that Gd@C₈₂(OH)₁₆ also gives high proton relaxivity, even higher than that of (NMG)₂-Gd-DTPA. The bio-distribution indicated that Gd@C₈₂(OH)₁₆ tends to be entrapped in the liver and kidney and remained in tissue for about 2 hours. The results suggest that the more stable metallofullerene derivative Gd@C₈₂(OH)₁₆ can be the potential candidate of the new MRI contrast agent.     

高碲酸合铜（Ⅱ,Ⅲ）配合物的合成和性质

在Ｈ６ＴｅＯ６／ＫＯＨ水溶液中以臭氧为氧化剂，将二价铜化合物氧化成三价铜化合物，并获得一个新的三价铜化合物Ｂａ４Ｋ［Ｃｕ（Ｈ２ＴｅＯ６）２］（ＯＨ）４．６Ｈ２Ｏ；描述了碱性溶液中“Ｃｕ（Ⅲ）／Ｃｕ（Ⅲ）”循环伏安图。对铜（Ⅲ）化合物，Ｎａ４Ｈ［Ｈ２ＴｅＯ６）２］．１７Ｈ２Ｏ以及相应的铜（Ⅱ）配合物的电子光谱和Ｃｕ２ｐＸＰＳ进行了研究，给出了其配位场场强参数和Ｃｕ２ＰＸＰＸ的电子结合能。由于价态升高     

二碘化铕的相变结构及荧光性质

本文用ＤＴＡ、Ｘ－ｒａｙ粉末衍射和荧光光度计等方法研究了ＥｕＩ２的相变和结构及荧光性质，用退火和淬火的方法得到了ＥｕＩ２的三种不同结构，并在荧光光谱上有不同的反映，首次发现ＥｕＩ２的低温变体，ＥｕＩ２－Ⅲ，正交晶系，空间群为ｐｎｍａ，ａ＝１．２２８７ｎｍ，ｂ＝０．４８８７ｎｍ，ｃ＝０．８３８４ｎｍ，Ｚ＝４。     

New catalytic effect of thiourea on the oxidative cyanation of N-aryltetrahydroisoquinolines

Thiourea itself has been introduced as a mild and efficient organocatalyst for the oxidative α -cyanation of N-aryltetrahydroisoquinolines (THIQs) with trimethylsilyl cyanide (TMSCN), giving the corresponding products in good to excellent yields. Experimental investigations demonstrated that thiourea acts as a radical initiator by abstracting hydroxyl radical (OH) from tert-butyl hydroperoxide (TBHP) directly instead of non-covalent hydrogen bondings (H-bondings) activation. The use of thiourea as a radical initiator offers a new avenue for innovative chemical transformations in organocatalyzed radical chemistry.     

四元交互体系Li~＋，Mg~（2＋）／Cl~－，SO_4~（2－）－H_2O

本文采用等温溶解平衡法研究了四元交互体系Ｌｉ＋，Ｍｇ２＋／ＣＩ－，ＳＯ－Ｈ２Ｏ２５℃的机关系和平衡液相的物化性质（密度、粘度、电导率、折光率和ｐＨ）．该体系２５℃有七个相区Ｌｉ２ＳＯ４·Ｈ２Ｏ，ＭｇＳＯ４·７Ｈ２Ｏ．ＭｇＳＯ４·６Ｈ２Ｏ．ＭｇＳＯ４·５Ｈ２Ｏ，ＭｇＣ１２，６Ｈ２Ｏ，ＬｉＣＩ．ＭｇＣｌ２．７Ｈ２Ｏ，ＬｉＣＩ·Ｈ２Ｏ，十一条单变量线，五个共饱点．其中ＬｉＣＩ·Ｈ２Ｏ＋ＬｉＣＩ·ＭｇＣｌ２·７Ｈ２Ｏ＋Ｌｉ２ＳＯ４·Ｈ２Ｏ为一致零变量点．与文献中的研究结果比较，我们得到两个新相区ＭｇＳＯ４·６Ｈ２Ｏ和ＭｇＳＯ４·５Ｈ２Ｏ．用经验和半经验公式计算了平衡液相的密度、折光率．由实验测定的溶解度数据求得了高锂浓度下的Ｐｉｔｚｅｒ参数．对该体系２５℃溶解度进行了理论计算复证．     

近红外漫反射光谱法对固态样品的无损分析

本文应用目标因子分析研究了固态样品的近红外漫反射光谱，用目标因子分析成功地确定了固态样品的物种数、物种种类和各物种的含量。     

热分析动力学数据处理方法的研究进展

综述了最近几年来用热分析法研究固相反应动力学的数据处理方法的新进展，指出了现有方法的成功与局限性，介绍了几种新的动力学处理方法及一种新的热分析技术。     

Kinetic and structural characterization of human manganese superoxide dismutase containing 3-fluorotyrosines

Incorporation of 3-fluorotyrosine and site-specific mutagenesis have been used with stopped-flow spectrophotometry and pulse radiolysis to investigate the catalytic properties of human manganese superoxide dismutase (MnSOD). All of the nine tyrosine residues in each of the four subunits of the homotetramer of human MnSOD were replaced with 3-fluorotyrosine. Previous studies showed that the crystal structures of the unfluorinated and fluorinated human MnSOD are nearly superimposable with the root-mean-square deviation for 198 -carbon atoms at 0.3 Å. However, the catalytic activity k_cat/K_m of the fluorinated MnSOD at 30 μM⁻¹ s⁻¹ was less than unfluorinated wild type at 800 μM⁻¹ s⁻¹. Comparison of the values of k_cat/K_m for fluorinated and unfluorinated wild-type andY34F MnSOD showed that this decrease for the fluorinated enzyme was in significant part due to 3-fluorotyrosine residues distant (>7 Å) from the active-site metal, not to 3-fluorotyrosine at position 34 close (5 Å) to the metal. Although many rate constants for the catalysis are decreased by this fluorination, the rate of dissociation of the product-inhibited complex appears unchanged by the presence of fluorinated tyrosines. These results suggest that Tyr34 is not a proton donor in the release of the product-inhibited complex, which involves protonation of a peroxo complex of the metal with release of hydrogen peroxide.     

Sexing Bovine Embryos Using PCR Amplification of Bovine SRY Sequence

This study analyses the bovine SRY DNA sequence by direct sequencing procedure, followed by the designation of the PCR primers specific for bovine SRY. Using PCR amplification of bovine SRY gene, the embryo sex was determined. The results of the embryo sex identification were confirmed after the embryo transfer and pregnancies.