Y2O2S∶Eu3+,Mg2+,Ti4+长余辉材料制备中烧结条件和助熔剂的影响

Y2O2S∶Eu3+;Mg2+;Ti4+长余辉材料制备中烧结条件和助熔剂的影响;Y2O2S∶Eu3+;Mg2+;Ti4+; 烧结条件; 助熔剂; 发光性质     

不具C2对称轴的Co（Ⅲ）（Salen)催化的末端环氧化合物的水解拆分

用（S）-3-甲基-1，2-丁二胺或（R）-1，2-丙二胺为原料与2-羟基-5-甲-3- 叔丁基苯甲醛缩合，得到不具C2对称轴的手性Salen, 与Co(Ⅱ）络各并氧化后得到 4a或4b.4a和4b成功地应用于外消旋末端环氧化合物的水解拆分，取得了较好的产 率，但产物的对映体过量值较低。     

光学活性配合物的合成、拆分和性能研究——Ⅲ.fac-、mer-〔Co(β-ala)3〕的手性固定相拆分和其对映体的异构化外消旋反应机理

本文用QAE-Sephadex-Sb_2(d-tart)_2~(2-)为手性交换固定相,50％乙醇水溶液为淋洗剂,在柱尺寸为80cm×2.2cm,淋洗速度为5.0ml/20min下完全拆分了1.0g fac-[Co(β-ala)_3];用同一手性固定相和淋洗剂在淋洗速度为1.2ml/20min下mer-[Co(β-ala)_3]的拆分量可增至0.78g。 fac-、mer-[Co(β-ala)_3]的四种对映体在1.56×10~(-2)M HClO_4介质和中性水溶液中的异构化外消旋反应的产物用Na~+型SP-Sephadex C-25柱分离后,用分光光度法和旋光仪测定了它们的浓度和旋光度。实验结果表明,这些对映体的异构化外消旋反应比较可能是按Werner首先提出的断键-分子内重排的机理进行。机理研究正在深入进行。     

大取代茂钼化合物的合成与结构分析

利用芳基锂与6,6-二烷基富烯发生加成反应,制得大取代环戊二烯基负离子。用六羰基钼配位,合成出13个钼—钼双核及5个钼—卤素单核羰基化合物.研究了其IR、~1H NMR、~(95)Mo NMR,测定了[(CH_3)_2C(m-CH_3C_6H_4)C_5H_4]Mo(CO)_3Br(1)的晶体结构.该晶体属于单斜晶系,晶胞参数为a=1.175(3),b=1.4196(2),c=1.1894(4)nm,β=118.03(2)°,V=1.75134 nm~3。Z=4,D_e=1.733g/cm~3,F(000)=904,μ=30.0cm~(-1),R=0.039,R_w=0.050,空间群为P2_1/α.     

棒状钡铁氧体的反相微乳法制备

A rodlike barium ferrite precursor with an average size of 0.72～19.6 μm and aspect ratio of 2.6～8.3 has been successfully prepared in an inverse microemulsion consisting of isooctane, cetanyl trimethyl ammonium bromide (CTAB), n-C₄H₉OH and water with ammonia and ammonium oxalate as precipitants. On sintering at 780(C, the rodlike precursor particles could be transformed into rodlike particles of barium ferrite(BaFe₁₂O₁₉) with the average size and aspect ratio of 0.69～18.2 μm and 2.3～5.8, respectively. The effect of volume ratio of aqueous phase to oleic phase, the starting concentrations of metal ions and the starting concentration ratios of metal ions to precipitants were investigated.     

手性配体立体选择性萃取分离扁桃酸对映体

Based on chiral ligand exchange, the distribution behavior of mandelic acid enantiomers in the two-phase system containing copper ion(Ⅱ)(Cu²⁺) and N-n-dedecane-L-hydroxyproline (L), was studied. At different pH, the partition of Cu²⁺ in the two-phase system containing N-n-dedecane-L-hydroxyproline, was investigated. The formation constant of binary cpmplex(Li₂Cu) was obtained by regression. The influence of pH, concentrations of Cu²⁺ and chiral ligand, and solvents on partition coefficients(K) and separation factor(α), was discussed. The experimental results show that Li forms more stable ternary complex with D-mandelic acid than with L- mandelic acid. There is a large influence of pH on K and α. At low pH values (<3.5), formation of binary complexes is thermodynamically unfavourable. K and α are best when pH values are above 3.5 and the molar ratio of chiral ligand to Cu²⁺ is 2∶1. At the same time, solvents influence K and α very much.     

有机/无机异质结薄膜发光二极管

聚合物发光二极管（LED）自从Burrou吵es等于1990年首次报导PPV的电致发光［‘］以来，由于聚合物半导体具有热和化学性能的稳定，克眼了有机小分子材料容易晶化的优点，在平板显示领域必将占有一席之地，从而吸引了许多科学家投身到这一领域来．众所周知，要想实现LED的实用化     

裂解色谱法研究PMR型聚酰亚胺前体的反应过程

用裂解气相色谱法研究ＰＭＲ型聚酰亚胺前体在反应中的化学变化过程，以裂解产物醇和环戊二烯的生成率表示酰胺化或酰亚胺化及交联的程度，结果表明，酰胺化或酰亚胺化在５０℃以下不发生，在１８０～２２０℃完成，降冰片烯端基在１５０℃以下不发生交联反应，在２８０℃，１０～１８小时可完成交联反应。