Engineering of Cardiotoxin by Chemical Synthesis: (I) Rapid Synthesis of Fully Active Cardiotoxin II and IV of Taiwan Cobra Venom

Two 60-residue snake toxins with four disulfide bridges, cardiotoxin II and IV, of Taiwan cobra (Naja naja atra) have been rapidly prepared in overall yields of 3.9% (cardiotoxin II) and 3.7% (cardiotoxin IV) within three weeks using the chemical method. Physicochemical characterization of these synthetic cardiotoxins was carried out by amino acid analysis, mass spectroscopy, capillary electrophoresis, peptide mapping, circular dichroism spectroscopy, and lethal toxicity. As compared with natural cardiotoxins, the results indicated that the synthetic cardiotoxins possessed the same physicochemical properties as those of natural ones. Therefore, in addition to preparation of various important toxins with satisfactory quantities for biochemical and pharmacological studies within a short lime, this rapid method also provides an important route to obtain many interesting toxins and designed toxin analogues for structure/function relationship studies in the near further.     

C207联醇催化剂的羰基硫中毒研究

以常压甲醇分解反应为基础实验测定了不同羰基硫含量和不同反应温度下甲醇合成铜基催化剂活性随时间的变化。结果表明，羰基硫含量增加时；失活速率增快；反应温度升高时，失活速率也加快。羰基硫中毒前后催化剂样品的ＸＲＤ谱图证实了起催化作用的活性组分为Ｃｕ＾＋／ＺｎＯ。应用改进的高斯－牛顿法对失活实验数据进行参数估值，获得了Ｃ２０７铜基催化剂羰基硫中毒的失活速率方程。     

Synthesis and Structure of the Hexanuclear Diazenido－oxomolybdate ［（n－C_4H_9）_4N］_3［Mo_6O_（18）（N_2C_6H_4－p－NO_2）］

ＳｙｎｔｈｅｓｉｓａｎｄＳｔｒｕｃｔｕｒｅｏｆｔｈｅＨｅｘａｎｕｃｌｅａｒＤｉａｚｅｎｉｄｏ－ｏｘｏｍｏｌｙｂｄａｔｅ［（ｎ－Ｃ_４Ｈ_９）_４Ｎ］_３［Ｍｏ_６Ｏ_（１８）（Ｎ_２Ｃ_６Ｈ_４－ｐ－ＮＯ_２）］ＬｉＨａｉ－Ｌｉａｎ；ＹｏｕＸｉａｏ－Ｚｅｎｇ；...     

Tunable N-substitution in zwitterionic benzoquinonemonoimine derivatives: metal coordination, tandemlike synthesis of zwitterionic metal complexes, and supramolecular structures

Full details on a very efficient transamination reaction for the synthesis of zwitterionic N,N-dialkyl-2-amino-5-alcoholate-1,4-benzoquinonemonoiminium derivatives [C6H2(=NHR)2(=O)2] 5-16 are reported. The molecular structures of zwitterions 5 (R=CH3) in 5.H2O, 13 (R=CH2CH2OMe), 15 (R=CH2CH2NMe2), and of the parent, unsubstituted system [C6H2(=NH2)2(=O)2] 4 in 4.H2O have been established by single-crystal X-ray diffraction. This one-pot preparation can be carried out in water, MeOH, or EtOH and allows access to new zwitterions with N-substituents bearing functionalities such as -OMe (13), -OH (9-12), NR1R2 with R1 = or not equal R2 (14-16) or an alkene (8), leading to a rich coordination chemistry and allowing fine-tuning of the supramolecular arrangements in the solid state. As previously described for 15, which reacted with Zn(acac)2 to afford the octahedral Zn(II) complex [Zn[C6H2(NCH2CH2NMe2)O(O)(NHCH2CH2NMe2)]2] (20), ligands 13 and 16 with coordinating "arms" afforded with Zn(acac)2 the 2:1 adducts [Zn[C6H2(NCH2CH2X)O(=O)(NHCH2CH2NX)]2] 19 (X=OMe) and 21 (X=NHEt), with N2O4 and N4O2 donor sets around the octahedral Zn(II) center, respectively. Furthermore, zwitterions 15 and 16 reacted with ZnCl2 to give the stable, crystallographically characterized Zn(II) zwitterionic complexes [ZnCl2[C6H2(NCH2CH2NR1R2)O(=O)(NHCH2CH2NHR1R2)]] 22 (R1=R2=Me) and 23 (R1=Et, R2=H) by means of an unprecedented, tandemlike synthesis in which 1) the two pendant amino groups of the organic benzoquinonemonoimine zwitterionic precursor favor metal coordination and proton transfer and 2) the saturated linker prevents pi-conjugation between the charges. The nature of the structural arrangements in the solid state for both inorganic (20, 22, 23) and organic (5, 9, 13, and 15) molecules is determined by subtle variations in the nature of the N-substituent on the zwitterion precursor.     

双－（3－烷基／芳基）－7H－1，2，4－三唑并[3,4-b]-1,3,4-噻二嗪类化合物的合成及波谱性质

利用1，4－二溴丁二酮（1）分别与3－烷基／芳基－4－氨基－5－巯基－1， 2，4－三唑（2a-2n）反应，合成了14种新的双－（3－烷基／芳基）－7H－1，2， 4－三唑并[3,4-b]－1，3，3-噻二嗪类化合物（3a-3n），并利用EA、IR，~1H NMR和MS确定了其结构。     

Asymmetric synthesis of (R)-S-(1,2,4-triazol-3-yl)cysteines by nucleophilic addition of triazolethiols to a NiII complex with a chiral dehydroalanine Schiff base

An efficient method was developed for the asymmetric synthesis of (R)-S-(1,2,4-triazol-3-yl)cysteines by the addition of 3,4-disubstituted 1,2,4-triazole-5-thiols at the electrophilic C=C bond in a Ni^II complex of a Schiff base of dehydroalanine with (S)-N-(N-benzylprolyl)aminobenzophenone. The stereoselectivity of the formation of diastereomeric complexes with the (S,R) configuration under conditions of thermodynamic control of the nucleophilic addition exceeds 94%. Acid treatment of the reaction mixtures afforded enantiomerically pure (R)-S-hetarylcysteines (ee >98%).     

One-pot oxidation of sulfides to sulfones by reusable heterogeneous ruthenium catalyst in the presence of molecular oxygen

A reusable solid catalyst, MnFe_1.8Cu_0.15Ru_0.05O₄, has been developed as an effective catalyst for the aerobic oxidation of sulfides and sulfoxides to sulfones. The ruthenium modified spinel catalyst is the first example reported for such reaction under mild condition with molecular oxygen as the only oxidant. The oxidation reaction proceeded via an electrophilic attack of the oxygen atom of the catalyst on the electron-rich sulfur atom of the substrate.     

Low‐Temperature Facile Template Synthesis of Crystalline Inorganic Composite Hollow Spheres

This report presents a facile approach for the low‐temperature synthesis of crystalline inorganic‐oxide composite hollow spheres by employing the bulk controlled synthesis of inorganic‐oxide nanocrystals with polymer spheres as templates. The sulfonated polystyrene gel layer can adsorb the target precursor and induce inorganic nanocrystals to grow on the template in situ. The crystalline phase and morphology of the composite shell is tunable. By simply adjusting the acidity of the titania sol, crystalline titania composite hollow spheres with tunable crystalline phases of anatase, rutile, or a mixture of both were achieved. The approach is general and has been extended to synthesize the representative perovskite oxide (barium and strontium titanate) composite hollow spheres. The traditional thermal treatment for crystallite transformation is not required, thus intact shells can be guaranteed. The combination of oxide properties such as high refractive index, high dielectric constant, and catalytic ability with the cavity of the hollow spheres is promising for applications such as opacifiers, photonic crystals, high‐κ‐gate dielectrics, and photocatalysis.     

掺铁纳米TiO_2的制备及其光催化性能

以TiC l4为原料,采用微波加热与常规加热2步合成法制备掺铁纳米TiO2。用X射线粉末衍射(XRD)、透射电镜(TEM)、紫外可见吸收光谱(UV-V is)、光电子能谱(XPS)等测试技术对其进行了表征。结果表明,所制得的掺铁纳米TiO2是以锐钛矿为主相的混晶,平均粒径约为10 nm,适量Fe3+的掺杂能促进金红石相变,抑制锐钛矿晶粒的生长,使Ti2p电子结合能升高0.3 eV,并使TiO2吸光能力增强,带边吸收向可见光区移动。在UVA段(320~400 nm)光照下,通过对维生素VB12的光催化降解,发现掺入摩尔分数为0.5%的Fe3+的纳米TiO2能明显提高其光催化活性,使维生素B12的降解速率提高2.3倍。     

Hybrid Tungstocuprate [Cu(2,2'-bpy)3]2H4[CuW12O40]·6H2O Based on Keggin Polyoxoanion [CuW12O40]6-with CuⅡas Heteroatom

A novel hybrid tungstocuprate(Ⅱ) [Cu(2,2'-bpy)3]2H4[CuW12O40]·6H2O(2,2'-bpy=2,2'-bipyridine) was synthesized via hydrothermal method and characterized using elemental analyses, IR, UV, XPS, TG-DSC, EPR, and X-ray single crystal diffraction. The structural analysis shows that the complex consists of an unusual Keggin-type polyoxoanion [CuW12O40]6- and a pair of chiral complex cations [Cu(2,2'-bpy)3] together with four protons and six crystallization water molecules, and the Keggin polyoxoanion is connected with [Cu(2,2'-bpy)3] via multiple C-H…O hydrogen bonds resulting in a dimer.