金属硫蛋白的聚合反应动力学

金属硫蛋白(Metallothionein,简称MT)是一类低分子量(哺乳动物MT的分子量为6500)、富含半胱氨酸(一般占氨基酸残量的30％)且具有高度可诱导性的金属结合蛋白。关于其结构与功能的研究是当今化学、生物学和临床医学等领域的重要课题之一。但是,有关各种生物MTs水溶液的热力学稳定性的研究尚未见报道。本文通过对在pH 7.40、4℃下放置不同时间的家兔肝脏(Cd,zn)_7MT水溶液进行HPLC分离,首次观察到MT在水溶液中的缓慢聚合现象,得到聚合反应的表观二级反应速率常数,发现MT-2比MT-1更易聚合。     

Ultraviolet photolysis of CH2I2 in methanol: O-H insertion and HI elimination reactions to form a dimethoxymethane product

Ultraviolet photolysis of low concentrations of CH2I2 in methanol solution found that CH2I2 is converted into dimethoxymethane and some H+ and I- products. Picosecond time-resolved resonance Raman (ps-TR3) experiments observed that the isodiiodomethane (CH2I-I) photoproduct decayed faster as the concentration of methanol increases, suggesting that isodiiodomethane is reacting with methanol. Ab initio calculations indicate isodiiodomethane is able to react with methanol via an O-H insertion/HI elimination to form an iodoether (ICH2-O-CH3) and HI products. The iodoether can then further react via another O-H insertion/HI elimination reaction to form the dimethoxymethane (CH3-O-CH2-O-CH3) observed in the photochemistry experiments. A reaction mechanism consistent with these experimental and theoretical observations is proposed.     

碳化钨负载S2O8^2-/ZrO2固体超强酸催化剂上的正戊烷反应研究

首次研究了碳化钨负载S2 O2 -8 ZrO2 (PSZ)固体超强酸催化剂 (WC PSZ)上正戊烷的反应情况及影响催化剂活性的各种因素 ,并用GC MS ,XRD ,BET等手段分析了正戊烷反应产物和催化剂的物理化学性质等 .结果表明 :WC PSZ对正戊烷具有异构化和裂解的双重催化作用 .PSZ在负载适量碳化钨后对正戊烷反应的活性和选择性显著提高 ,显示出优于Pt PSZ催化剂的效果 ,碳化钨的负载量为 2 0 %的效果最佳 .适当的焙烧、活化和反应温度等条件是取得良好反应效果的关键     

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.     

Studies on the phase properties of lyotropic liquid crystals of Brij35/sodium oleate/oleic acid/water system:By means of polarizing microscope,SAXS,~2H-NMR and rheological methods

The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/water systems has been investigated, and the liquid crystal area has been identified, which covers about two thirds of the whole phase diagram. The liquid crystal structure and behavior have been also studied by using polarizing texture, small angle X-ray scattering, 2H-NMR and rheometer etc. The result shows that when the composition of the system changes along the line of AA′ in this large liquid crystal region, the structural change is cubic→cubic/lamellar→lamellar→lamellar/hexagonal→hexagonal. Meanwhile, we made the first attempt of systematic study of the rheological properties of the above system. The lattice constants of cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.     

芳香基团修饰的三联吡啶钌(Ⅱ)配合物光物理性质及其光损伤CT-DNA研究

钌(Ⅱ)多吡啶配合物具有丰富的光物理和光化学性质,在无机生物光化学的发展和应用中发挥了重大作用.例如,作为高效DNA光断裂试剂,钌(Ⅱ)多吡啶配合物已经得到广泛而深入的研究.     

Fe(Ⅲ)与两种4-羟基吡啶二酸形成的配合物的合成与晶体结构

0 引言 最近,我们对2,6-吡啶二酸的衍生物4-羟基-2,6-吡啶二酸(2,6-HAD)的配合物进行了一系列的研究,结果发现2,6-HAD是一个优良的刚性配体,其配位方式种类繁多,特别是配体上的4位羟基,既具有较强的配位能力[1],又可以形成分子间氢键[2,3],影响和控制配合物的超分子结构,4-羟基-2,6-吡啶二酸不仅能与过渡金属、镧系金属离子分别形成稳定的配合物[1-3],而且能同时与稀土和过渡金属形成具有纳米孔穴的混金属配合物,这些配合物在磁性、光学等方面都显示出优异的性能[4].     

(AB)8(AB=BN，AlP，GaAs，InSb)团簇环状结构与性质的密度泛函理论研究

用杂化密度泛函B3LYP方法研究了(AB)₈(AB=BN，AlP，GaAs，InSb)团簇环形结构的平衡几何构型、电子结构、振动特性以及极化率。计算结果表明，(AB)₈团簇的双层环状结构中，每个A(B)原子都与3个B(A)原子成键，且Ⅴ族元素的原子比Ⅲ族元素的原子更接近团簇中心，(BN)₈、(AlP)₈、(GaAs)₈、(InSb)₈的平均极化率依次增大，IR和Raman谱峰发生红移。另外，讨论了热力学稳定性和动力学稳定性的变化。     

磺化β-环糊精毛细管电泳法分析对氯苯乙二醇对映体的光学纯度

光学活性对氯苯乙二醇(p-chlorophenyl-1,2-ethaned iol,PC-d iol)被广泛应用于许多重要手性化合物和手性药物的合成[1]。在金鸡钠生物碱衍生物配体存在下对氯苯乙烯的不对称二羟化(AD)反应是制备该手性物质最重要的方法之一[2]。而进一步发展该手性物质的高效拆分技术和方法对