流动注射分光光度法测定微量硫氰酸根

基于３，５－Ｂｒ２－ＰＡＤＡＰ硫氰酸根分别与重铬酸根，铈（ＩＶ）在硫酸介质中反应成不稳定的蓝色产物，建立了两种测定微量硫氰酸根的流动注射分光光度新方法，在前一方法中，硫氰酸根含量在０．８０～７．２０ｍｇ／Ｌ范围内可定量测定，检出限为０．２７ｍｇ／Ｌ在后一方法中，硫氰酸根含量在０．８０～６．４０ｍｇ／Ｌ范围内呈线性，检出限为０．３０ｍｇ／Ｌ。当进样体积为１００μＬ时，进样频率为６０次／ｈ，所建立的两     

（C_5H_5）_3Nd（THF）的晶体结构

报导了一种新型（Ｃ_５Ｈ_５）３Ｎｄ（ＴＨＦ）晶体结构，晶体属单斜晶系，Ｃ２／ｃ空间群，晶胞参数为ａ＝１２．８３９（７），ｂ＝１０．５２０（３），ｃ＝２６．５９９（９），β＝９８．５０°，Ｖ＝３５５３（３），Ｚ＝８，Ｄ_ｃ＝１．５４ｇ／ｃｍ￣３，Ｍ_ｒ＝４１１．６３，μ＝２９．２９ｃｍ（－１），Ｆ（０００）＝１６４０，最终偏离因子为Ｒ＝０．０６１，Ｒｗ＝０．０７３。新晶体结构在空间群、晶胞参数和Ｚ值上均明显不同于前面的报导，在Ｃｐ３Ｌｎ·ＴＨＦ系列化合物中，这是首次发现同一化合物可以用两种分子堆积方式结晶。     

金属置换碳酸酐酶及其生成动力学

本文报道了金属置换碳酸酐酶的活性研究。指出了离子半径的大小,配位构型的要求,热力学稳定性和配位体交换动力学是决定各种金属置换碳酸酐酶活性的重要因素。并用金属置换法测定了Ni(Ⅱ)与apo-CA形成金属酶的反应动力学速率常数。在25℃、pH7.47时,K_(fNi(Ⅱ)-CA)为14.01·mol~(-1)sec~(-1),较之于Zn(Ⅱ)-CA的速率常数小10~3倍。Cd(Ⅱ)-CA的生成动力学为一快反应,采用配位竞争法,在邻菲罗啉配位剂存在下,测得了Cd(Ⅱ)-CA生成动力学的条件速率常数在o-phen浓度为1.96和2.92×10~(-4)mol·1~(-1)时分别为137.1和114.61·mol~(-1)sec~(-1)。这一研究提示了镉对生物体的毒性作用的一个重要方面是使锌酶失活。而配位剂的存在大大降低了镉与脱辅基锌酶的反应动力学,这也是它们显示解毒功能所在。     

New ammonia equivalents for the Pd-catalyzed amination of aryl halides

[reaction: see text]. LiN(SiMe3)2, Ph3SiNH2, and LiNH2 can be be used as ammonia equivalents for the Pd-catalyzed coupling of aryl halides. Using these amine derivatives, simple anilines, including ortho-substituted ones, as well as di- and triarylamines can be readily prepared.     

Detection of a thermally unstable intermediate in the Wittig reaction using low-temperature liquid secondary ion and atmospheric pressure ionization mass spectrometry

The signal of an extremely air sensitive and thermally unstable intermediate, four-membered ring oxaphosphetane in the Wittig reaction was detected for the first time at subambient temperature using liquid secondary ion mass spectrometry (LSIMS) and atmospheric pressure ionization (API) mass spectrometry. A copper probe and interface were constructed to perform LSIMS analysis at the temperature below ?70 °C. A stable signal from a oxaphosphetane ion [in dry tetrahydrofolate (THF)] was obtained by LSIMS without using a viscous matrix. The signal of the oxaphosphetane was also detected using a low-temperature API source (?40 °C) connected to a reaction vessel.     

Detection of metalloproteins in human liver cytosol by synchrotron radiation X-ray fluorescence combined with gel filtration chromatography and isoelectric focusing separation

Synchrotron radiation X-ray fluorescence (SRXRF) spectroscopy is an advanced method of quantitative multielemental analysis with space resolution of several microm and sensitivities in the microg g(-1) range. It can be used for keeping track of trace elements after an electrophoretic separation of biological samples. In this paper, proteins in human liver cytosol were separated with gel filtration chromatography and thin layer isoelectric focusing (IEF). The contents of metal ions in protein bands were determined by SRXRF. The results showed that in the molecular weight (MW) range of 10 approximately 25 kDa, there were at least 2 Zn-containing bands with isoelectric point (pI) of 5 approximately 6 and 6.2 approximately 7, respectively and about 11 Fe-containing proteins with pI of 4.4, 4.6, 4.8, 5.0, 5.2, 5.3, 5.5, 5.6, 6.6, 6.8, and 7.2, respectively, present in human liver cytosol. The Zn-containing band with pI of 5-6 is the dominant species of zinc in this MW range. In addition, the Cu-containing bands with pI of 5.0 and below 4.8 were also detected. It is demonstrated that the procedure could be widely used in further investigations of the chemical species of trace elements in biological samples.     

全氟烷基碘化物化学的新进展

本文讨论了全氟烷基碘化物在金属有机化学、自由基化学以及有机合成上的新进展与应用。近来对全氟烷基腆化物的研究兴趣日增,主要因为由R班(全氟烷基碘化物)可以方便地获得各种全氟烷基的金属有机化合物和各种全氟烷基自由基.R班也是一个重要的中间体,由它出发可以得到有各种官能团的含氟有机化合物,如一50:CI;一C00H;一poaH;一CF=CF:;一NO:;一Mgl;一X(X表示碘以外的其它卤素);一H;一SR等。另外,虽然在碳氟和碳氢碘化物中,碳