停止-流动分光光度法研究铕(II)与二甲酚橙快速电子转移反应动力学

用停止-流动分光光度法研究了Eu~(2+)与二甲酚橙(XO)间快速电子转移反应的动力学规律。求得了速控步骤的动力学参数。如反应级数(n=2)、几个不同温度下的速率常数(k_(278 K)=5.7×10~8 L·mol~-·s~(-1), k_(s38 K)=1.01×10~9 L·mol~(-1)·s~(-1))、活化能(E=7.6×10~3 J·mol~(-1)), 以及指前因子(A=1.5×10~(10) L·mol~(-1)·s~(-1)), 并判断出其为溶液中扩散控制型反应。根据实验现象与测试结果, 提出了Eu~(2+)与XO的反应分别在Eu~(2+)相对过量和在XO过量时的反应机理, 并判断了各反应步骤速率常数之间的相对关系。     

铝镓取代的钨硅杂多配合物位置异构体的合成表征及催化性能

合成了通式为Ｋ５－ｎＨｎ［α－，βｉ－ＳｉＷ１１Ｍ（Ｈ２Ｏ）Ｏ３９］·ｘＨ２Ｏ（Ｍ＝Ａｌ，Ｇａ，βｉ＝β１，β２，β３）的八种异构体。通过元素分析、红外光谱和紫外光谱、极谱和循环伏安、２７Ａｌ和１８３Ｗ核磁共振、Ｘ光电子能谱等方法进行了表征。所合成的各异构体在催化以Ｈ２Ｏ２为氧化剂的顺丁烯二酸环氧化反应中，β３异构体具有最高的催化活性     

NMR and Excess Volumes Studies in DMF–Alcohol Mixtures

Chemical shifts of the alcohol and DMF protons in DMF–alcohol mixtures with the mole fraction of alcohol are reported in order to study the hydrogen bond interaction present in the mixtures. The densities of DMF–methanol mixture at 22°C are also measured. Excess volumes and excess chemical shifts are correlated by the Redlich–Kister equation. The relation between excess volumes and excess chemical shifts in the mixtures is discussed. It is found that the maximum excess chemical shifts ^E(CHO-OH) and ^E(CH₃-OH) are positioned at about mole fraction methanol = 0.57 for the DMF–methanol system, as is V ^E. The results show that the NMR spectral method offers a valuable approach to similar future studies of interactions in mixtures.     

加速剂对化学镀镍层组成与结构的影响

加速剂对化学镀镍层组成与结构的影响方景礼，武勇，韩克平，张敏（南京大学应用化学研究所配位化学国家重点实验室南京２１００９３）关键词化学镀镍，Ｎｉ０Ｐ合金，加速剂，硫脲化学镀镍磷合金具有耐蚀性、可焊性、厚度均匀和硬度高等优点，已得到广泛应用。为提高生产...     

STUDIES ON THE MORPHOLOGY OF SOME PERFLUORO (ETHYLENE-PROPYLENE) COPOLYMERS BY SMALL ANGLE LIGHT SCATTERING TECHNIQUE

The crystalline morphology of some FEP copolymers, prepared by different methods, with different hexafluoropropylene (F_6) contents was studied by means of small angle light scattering technique.The results obtained show that the main factors which affect the crystalline morphology are the content of F_6 and the conditions for crystallization. The morphological structure of these copolymers could change from rod-like to spherulitical, as the F_6 content changed from 2% to 14—19% under usual air-quenching condition. However, rod-like crystalline structure would form under very low rate of cooling (0.2℃/min). Some H_v patterns show that fine structure also exists in addition to the two—and three-dimensional spherulites coexisting in the specimens prepared under certain crystallization conditions.     

Swelling kinetics and release characteristic of crosslinked chitosan: Polyether polymer network (semi-IPN) hydrogels

The aqueous swelling kinetics of a series of crosslinked chitosan (cr-CS) with glutaraldehyde (GA) interpenetrating polyether hydrogels have been studied as functions of pH, the N-deacetylation degree of chitosan, the amount of crosslinking agent, the electrolyte composition in solution, temperature, and gel composition. Based on these results, the swelling mechanism of the hydrogels was discussed. The release profiles of chlorhexidini acetas from the semi-IPN were also investigated. © 1994 John Wiley & Sons, Inc.     

Photodegradation of a 1,3,4-thiadiazole-urea herbicide. Isolation,characterization, X-ray crystal structure and synthesis of photoproducts

The photodegradation of 1,3-dimethyl-1-(2-(3-fluorobenzylthio)-1,3,4-thiadiazol-5-yl)urea as a thin film and in solution is described. The two photoproducts from thin-film photolysis were characterized by spectral and synthetic methods. The X-ray crystal structure of one of the photoproducts is also reported. The rearrangements were shown to involve an S-to-N benzyl migration, followed by a sulfur-oxygen substitution.     

Synthesis of 1,2,3,4,8,9,10,11-octahydro-[1,4] diazepino[6,5,4-jk ]earbazole and related compounds

1,2,3,4,8,9,10,11-Octahydro[1,4]diazepino[6,5,4-jk]earbazole (VIa) was synthesized from 2,3,4,5-tetrahydro-1H-benzodiazepine (la) via the route shown in Scheme 1. Other compounds which were prepared similarly are 3-acetyl-6-chloro-1,2,3,4,8,9,10,11-octahydro[1,4]diazepino-[6,5,4-jk]carbazole(Vb) and 3-methyl-1,2,3,4,8,9,10,11-octahydro[1,4]diazepino[6,5,4-jk]carb-azole (VIII). Chemical transformations which were carried out with VI and 3-acetyl-1,2,3,4,8,9, 10,11-octahydro[1,4]diazepino[6,5,4-jk]carbazole (Va) are also described.     

Ordered porous films based on fluorinated polyimide derived from 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 3,3′-dimethyl-4,4′-diaminodiphenylmethane

One of fluorinated polyimides was synthesized from 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dimethyl-4,4′-diaminodiphenylmethane (DMMDA) by two-steps method, which had good solubility and hydrophilicity. 6FDA-DMMDA polyimide was dissolved in chloroform (CHCl₃) and cast on a glass substrate in a humid atmosphere. It was found that 6FDA-DMMDA/CHCl₃ solution was easy to form ordered porous structure at high concentration, and the reason was discussed in detail. In addition, the influences of solution concentration, the atmosphere humidity, were also tested.     

Quantum scattering calculation of the O(1D)+HBr reaction

Three-dimensional time-dependent quantum wave packet calculation for the O((1)D)+HBr reaction has been carried out using an accurate ab initio global potential energy surface [K. A. Peterson, J. Chem. Phys. 113, 4598 (2000)]. The calculations show that the initial state-selected reaction probabilities are dominated by resonance structures, and the lifetime of the resonance is generally in the subpicosecond time scale. The energy dependence of the reaction cross section is computed, which manifests still resonance structures, and is a decreasing function of the translational energy. The thermal rate constants are also computed, which are nearly independent on the temperature. The calculation results are discussed and compared to similar reaction with deep well.