取代茚基稀土配合物/添加剂体系催化丙烯腈聚合

研究了取代茚基稀土配合物 /添加剂体系对丙烯腈的聚合 ,发现季胺盐及芳氧钠是取代茚基二价稀土配合物催化丙烯腈聚合的有效添加剂 ,其中Me3NC1 6 H33Br效果最好 ,5种二价稀土配合物 (C5H9C9H6 ) 2 Yb (THF) 2 ,(C5H9C9H6 ) 2 Sm (THF) 2 ,KSm (C5H9C9H6 ) 3(THF) 3,(PhCH2 C9H6 ) 2 Sm(THF) 2 和 (CH3CH2 C9H6 ) 2 Sm (THF) 2 与Me3NC1 6 H33Br构成的催化体系对于丙烯腈聚合都显示出好的催化活性。对(C5H9C9H6 ) 2 Yb(THF) 2 /Me3NC1 6 H33Br体系而言 ,在丙烯腈中当催化剂用量为 2× 10 - 5mol·g - 1时 ,丙烯腈聚合的最大转化率为 61%。     

高效液相色谱法测定地顶孢霉培养物中的腺苷

建立测定虫草源饲料添加剂地顶孢霉培养物中腺苷含量的高效液相色谱方法。样品经过研碎、超声处理,离心、过滤后上机测定。腺苷的最佳提取条件:以超纯水为浸提液,用超声波浸提,浸提温度为40℃,浸提时间为55 min。使用Waters Spherisorb ODS2柱(150 mm×3.9 mm,5μm),以甲醇-0.01 mol/L磷酸二氢钾混合液(10∶90)为流动相,流量为1.0 mL/min,进样体积为20μL,检测波长为254 nm。腺苷的质量浓度在0.5~100μg/mL范围内与色谱峰面积成良好的线性关系,相关系数为0.9990。样品测定结果的相对标准偏差为1.65%(n=6),3水平加标的平均回收率为98.19%。该方法简便、快捷,可准确测定虫草饲料添加剂地顶孢霉培养物中腺苷的含量。     

镧系与二甘醇-二-(邻羟基苯基)醚配合物的合成与表征

本文合成14种镧系高氯酸盐及硝酸盐分别与二甘醇-二-(邻羟基苯基)醚(记为EO_2(HOP)_2,EO=ethylene oxide,HOP为邻羟基苯基)形成的新配合物,确证组成为Ln(ClO_4)_3·EO_2(HOP)_2·nH_2O(Ln:La-Eu,n=10,Ln:Gd,Dy-Tm,Y,n=7),La_3(NO_3)_9·(EO_2(HOP)_2)_2·3H_2O及La(ClO_4)_2·EO_2H(OP)_25H_2O。文中研究了配合物红外,紫外、~1HNMR谱及~(13)C纵向弛豫时间T_1等,并讨论了共存阴离子、溶剂及配体不同端基对成配的影响。     

东亚马氏钳蝎哺乳动物类神经毒素III的快原子轰击酶谱分析

应用快原子轰击酶谱分析检验了东亚马氏钳蝎哺乳动物类神经毒素III的氨基酸序列,对前人用Edman降解法测定的序列作了两处修正:(1)第60位氨基酸残基是脯氨酸而不是色氨酸;(2)C-端氨基酸是组氨酸而不是甘氨酸。分别用羧肽酶B降解和部分胰蛋白酶酶解后的质谱数据进一步证实了以上的修正。在分析中采用了化学修饰方法以减少表面抑制效应,从而得到完整的快原子轰击酶谱。     

酰亚胺及磺酰苯酰亚胺的氰甲基化新方法

二乙胺基乙腈分別与苯邻二酰亚胺、丁二酰亚胺或邻-磺酰苯酰亚胺反应后,可生成相应的N-氰甲基苯邻二酰亚胺、N-氰甲基丁二酰亚胺,N-氰甲基邻磺酰苯酰亚胺及O-氰甲基邻磺酰苯酰亚胺。酰亚胺或磺酰苯酰亚胺的氰甲基化反应活性,随氮负离子的稳定性及其酸性增强而增大。     

离子液体介导CO2化学转化研究进展

The efficient utilization of carbon dioxide (CO₂) as a C1 feedstock is of great significance for green and sustainable development. Therefore, the efficient chemical conversion of CO₂ into value-added products has recently attracted a lot of research attention in recent years. The transformation of CO₂ generally requires high-energy substrates, specific catalysts, and harsh reaction conditions due to its high thermodynamic stability and kinetic inertness. Consequently, several efforts have been dedicated toward the development of high-performance catalysts and new reaction routes for CO₂ conversion over the last few decades. To date, many routes of convert CO₂ into value-added chemicals have been proposed, together with the development of heterogeneous and homogeneous catalysts. Among the advanced catalysts reported to date, ionic liquids (ILs) have been widely investigated and show great potential for the efficient, selective, and economical conversion of CO₂ into highly valuable products under mild conditions, even under ambient conditions. Some task-specific ILs have been designed with unique functional groups (e.g., —OH, —SO₃H, —NH₂, —COOH, and —C≡N), which can act as the solvent, absorbent, activating agent, catalyst, or cocatalyst to realize the transformation of CO₂ under metal-free and mild conditions. In addition, a variety of catalytic systems composed of ILs and metal catalysts have also been reported for the transformation of CO₂, in which the combination of the IL and metal catalyst is responsible for CO₂ conversion with high efficiency. In this review article, we summarize the recent advances in IL-mediated CO₂ transformation into chemicals prepared via C—O, C—N, C—S, C—H, and C—C bond forming processes. ILs that can chemically capture CO₂ with high capacity are first introduced, which can activate CO₂ via the formation of IL-based carbonates or carbamates, thus realizing the transformation of CO₂ under metal-free and mild conditions. Recent progress in IL-mediated CO₂ transformations to form carbonates and various kinds of N- and S-containing compounds (e.g., oxazolidinones, ureas, benzimidazolones, formamides, methylamines, benzothiazoles, and other chemicals) as well as CO₂ hydrogenation to give formic acid, methane, acetic acid, low-carbon alcohols, and hydrocarbons has been summarized in this review with a focus on the reaction routes, catalytic systems, and reaction mechanism. In these reactions, ILs can simultaneously activate the substrate via strong H-bonding in addition to activating CO₂, and the cooperative effects among the ionic and molecular species and metal catalysts accomplish the reactions of CO₂ with various kinds of substrates to afford a wide range of value-added chemicals. Finally, the shortcomings and perspectives of ILs are discussed. In short, IL-mediated CO₂ transformations provide green and effective routes for the synthesis of high-value chemicals, which may have great potential for a wide range of applications.     

M_nP_m~+原子簇结构的ab initio从头算(M=Cr,Mn,n=1～3,m=2～12)

应用ahinitio计算程序，我们对飞行时间质谱产生的谱图进行了理论分析。稳定的MnnPm+和CrnPm+的结构基本上是多面体，仅有少数结构为环状和平面的。在计算中，我们尚未发现有链状的簇合物，这与风簇绝大多数是多面体是相一致的。因此，单枚金属簇合物的形成机制很大可能是金属进入磷形成的笼簇中。一般地说，除了磷的个别笼状团簇外，金属和磷相互成键是普遍存在的；在二核、多核金属磷簇合物中，金属间相互作用不常见，绝大多数是通过桥磷相连的。     

八元瓜环与啡咯啉及其衍生物主客体配合物的研究

利用¹H NMR技术、荧光光谱法, 对八元瓜环与多种啡咯啉及衍生物相互作用形成的主客体配合物实体的结构进行了考察. 研究结果显示, 1,10-啡咯啉及其异构体1,7-啡咯啉、4,7-啡咯啉的盐酸盐“钻”进八元瓜环内腔, 形成2︰1自组装主客体包结物; 2,9二甲基-1,10-啡咯啉的盐酸盐部分进入八元瓜环形成一种比较稳定的主客体配合物; 而4,7-二甲基-1,10-啡咯啉、3,4,7,8-四甲基-1,10-啡咯啉以两种不同的π-π堆砌方式部分进入八元瓜环内腔, 形成包结比也是2︰1的两种较稳定的自组装主客体配合物异构体.     

尼龙6,6(PA_(6,6)及其共混物结晶性能的研究

<正> 尼龙6,6(PA_(6,6))是一种典型的结晶性工程塑料,被广泛应用于纺织、机械制造等行业,但其加工温度范围较窄,耐热性差。聚醚砜(PES)具有较高的玻璃化转变温度,是非晶聚合物,可以诱发某些结晶聚合物结晶。PES与PA_(6,6)共混体系的研究报道较少,本文用熔融法将PES与PA_(6,6)制成共混物,企图改善PA_(6,6)的结晶性,以提高其耐热性,取得了较理想的结果。