钠硼解石——水体系溶解和相平衡的研究(英)

Ulexite dissolution in water has been studied in the wide temperature range from 10℃ to 93℃ and two higher temperatures at 120 ℃ and 240 ℃. The analytical results showed that ulexite dissolved congruently from 10 ℃ to 35 ℃ and incongruently from 40 to 68 ℃. The solid component of ulexite, NaCaB₅O₆(OH)₆·5H₂O was dehydrated to form NaCaB₅O₆(OH)₆·H₂O from 50 to 68 ℃ and finally amorphous solid at 68 ℃. This amorphous solid converted into priceite at 71 ℃ and then converted completely to priceite at the boiling point(93℃) of the solution. At both 120 and 240 ℃, the dissolution of ulexite was an incongruent process. Above 120 ℃, ulexite became amorphous solid and then transformed into priceite. In addition to the solid to solid transformation, crystallization of priceite from the solution has also been observed. Based on our experimental results, mechanisms of dissolution, transformation, and crystallization of borate in ulexite-water system are discussed.     

次甲基硅SiH与H2X(X=O,S)反应的热力学及动力学性质研究

在量子化学对SiH与H₂O和H₂S反应计算的基础上,运用统计热力学和Wigner校正的Eyring过渡态理论,计算了上述两反应在200～2000 K温度范围内的热力学函数、平衡常数、频率因子A和速率常数随温度的变化。计算结果表明,两反应在低温下具有热力学优势,而在高温下具有动力学优势。比较两反应的计算结果发现,在相同的温度下,SiH与H₂O反应比SiH与H₂S反应放热较多,但速率常数却较小。SiH与H₂O反应和前文报道的SiH与HF反应的比较表明,SiH与H₂O反应放热较少,而且在相同温度下,速率常数也较小。     

倒数示波计时电位滴定新技术

倒数交流示波极谱具有抑制充电电流、突出电解电流的优点,利用(dE/dt)~(-1)-E曲线上去极剂峰的突然消失或出现指示滴定终点的方法称作倒数示波计时电位滴定法.由运算放大器组装的模拟电子线路可以对(dE/dt)~(-1)-E曲线进行反馈、反对数及微分处理,从而获得各种类型的倒数示波计时电位曲线(图1),以进一步提高滴定的灵敏度。     

选相示波伏安法

选相示波伏安法毕树平，都思丹，高鸿（南京大学化学系，２１０００８）关键词示波计时电位法，选相示波伏安法，切口示波计时电位法是利用ｄＥ／ｄｔ～Ｅ曲线上切口的高度或深度进行定量分析的方法［１］，但由于ｄＥ／ｄｔ曲线主要反映充电电流的变化，从而使该方法的检...     

Index Abstracts

Abstract

Calorimetric titrations have been performed in anhydrous acetonitrile at 25°C to give the complex stability constants (K _s) and the thermodynamic parameters (ΔGΔ, ΔHΔ and ΔSΔ) for the complexation of light lanthanoid(III) nitrates (La-Gd) with N-benzylaza-21-crown-7 3. Data analyses, assuming 1:1 stoichiometry, were successfully applied to all light lanthanoid-azacrown ether combinations employed. Using the present and previous data on 15- to 21- membered N-benzylazacrown ethers 1–3, the effect of ring size upon complexation behavior was discussed comparatively and globally from the thermodynamic point of view. The complexation behaviors are analyzed in terms of the size-fit concept, N-substituent coordination numbers, and lanthanoid's surface charge density. Thermodynamically the complexation of light lanthanoids with azacrown ethers is enthalpy-driven, while the cation selectivity is generally entropy-driven in acetonitrile.     

甲氨蝶呤/层状双金属氢氧化物的性能调控及细胞生物实验研究

在乙醇-水混合体系中,以氨水为沉淀剂共沉淀合成了甲氨蝶呤/层状双金属氢氧化物(MTX/LDH)纳米复合物,采用控制水热处理时间的方式来调控其性能。利用X-射线衍射(XRD)、透射电镜(TEM)和红外光谱(FT-IR)等表征手段,对其结构及形貌进行了表征。研究表明:MTX分子以单层倾斜或垂直方式插入LDH层间,随着水热处理时间的不同,MTX在层间的倾斜角度发生了变化;水热处理时间对产物的结晶度、粒径和层间排列方式都有影响,当水热处理时间为12h时,得到的MTX/LDH纳米复合物的结晶度最高,单分散性最好。在磷酸缓冲液中考察了MTX/LDH纳米复合物的缓释性能,结果表明样品均呈现出良好的缓释性能,释放速率先快后慢。重点考察了这几种MTX/LDH纳米复合物作用于肺癌细胞A549的细胞生物实验,研究表明这几种复合物对肺癌细胞A549都具有良好的抑制作用,其效果与纳米复合物的单分散性和粒径有密切的关系,单分散性越好,粒径分布越均匀,对A549癌细胞的抑制效果越好。     

Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H2O)3]

1 INTRODUCTION Nitronyl nitroxides, independently or in combina- tion with metal ions, have been one of the most wi- dely studied systems in molecular magnetism for understanding radical-radical or metal-radical inte- ractions as well as for synthesizing organic ferroma- gnets and metal-radical magnetic materials[1～4]. Up to now, lots of metal-radical complexes have been reported[5～8]. On the other hand, cooperative inter- molecular interactions, such as coordination bonds, hydrogen bon…     

苊酮对二氰蒽的电子转移荧光猝灭研究──激基络合物的形成机理与动力学

研究了苊酮（ＡＮＯ）对９，１０－二氰蒽（ＤＣＡ）的荧光猝灭与激基络合物形成的动力学与机理。基于瞬态荧光双指数衰减，测定了激基络合物的光化学动力学和有关速度常数，论证荧光猝灭作用主要由ＡＮＯ／ＤＣＡ激基络合物的生成以及快速正向电子转移所致。     

烷氧基菲咯啉设计合成及其氮磷杂配铜光敏剂的光解水制氢性能

以功能化氮配体为导向,以4,7-二苯基-1,10-菲咯啉为原料,经季铵化、氧化、卤化和醚化合成了一类新型的2,9-二烷氧基-4,7-二苯基-1,10-菲咯啉配体5a~5e。再以Xantphos为膦配体,通过原位配位方法合成一系列氮磷杂配铜光敏剂（CuPS A~H）,在均相光解水制氢体系中研究其光敏活性。制氢结果表明,以2,9-二乙氧基为较佳取代基,CuPS D的催化产氢总转换数（TON）可达270。在光电物理性能分析中,发现这类杂配铜配合物都有一个相似的氧化还原电位（E^oxd=-0.8 V,E^red=-1.2 V）。具有乙氧取代基的铜配合物CuPS D相对于其他取代基的铜基配合物,荧光最弱,表明乙氧基有助于提高荧光淬灭效率,增强铜光敏剂的光化学转换能力。     

SERS标记纳米粒子用于免疫识别

激光拉曼光谱技术近年来已成为研究生物分子结构常用的光谱手段.尤其在研究水溶液中蛋白质的结构和构象方面发挥了重要作用.然而,常规拉曼光谱的信号强度很低,限制了其在各个领域中的应用.表面增强拉曼光谱(SERS)和表面增强共振拉曼光谱(SERRS)技术可使信号增强6～10个数量级,尤其是SERS技术已发展到检测单分子的水平,更为其在生物方面的应用开拓了新的局.