Mechanisms of sodium and potassium ions transfer facilitated by dibenzo-15-crown-5 across the water /1,2-dichloroethane interface using micropipettes

The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/1,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic volt-ammetric measurements were performed in two limiting conditions: the bulk concentration of Na+ or K+ in the aqueous phase is much higher than that of DB15C5 in the organic phase (DB15C5 diffusion controlled process) and the reverse condition (metal ion diffusion controlled process). The mechanisms of the facilitated Na+ transfer by DB15C5 are both transfer by interfacial complexation (TIC) with 1 : 1 stoichiometry under these two conditions, and the corresponding association constants were determined at log beta(1) = 8.97 +/- 0.05 or log beta(1) = 8.63 +/- 0.03. However, the transfers of K+ facilitated by DB15C5 show different behavior. In the former case it is a TIC process and its stoichiometry is 1 : 2, whereas in the latter case two peaks during the forward scan were observed, the first of which was confirmed as the formation of K (DB15C5)(2) at the interface by a TIC mechanism, while the second one may be another TIC process with 1 : 1 stoichiometry in the more positive potential. The relevant association constants calculated for the complexed ion, K+(DB15C5)(2), in the organic phase in two cases, logbeta(2), are 13.64 +/- 0.03 and 11.34 +/- 0.24, respectively.

新型化合物[Ni(en)_3]_2[Ni(en)_2(H_2O)_2]·[As_6V_(15)O_(42)]·4H_2O晶体的水热合成与表征

多金属氧酸盐因其在医药临床、工业催化、功能材料等方面的广泛应用而引起人们的关注 [1～ 6 ] ,其中 ,有关钒化学的研究一直很活跃 ,钒具有与钼、钨明显不同的结构特性 ,钒可以采取 VO4 ,VO5和VO6 方式配位 ,同时 ,钒的价态可以是 + 3,+ 4和 + 5价 .由于钒可采取多种配位方式及多种价态 ,与钼酸盐和钨酸盐相比 ,钒酸盐更具有结构柔顺性 ,同时易形成低价或混合价态物种 .在以往的文献中 ,有关 P- V- O体系多金属氧酸盐的水热合成的研究已有大量的报道 [7] ,在常规溶液合成中 ,人们已对As- V- O体系进行了相对深入的研究 ,而有关水热合成的研究报道却很少 ,已见报道的砷钒化合物有K6 [As6 V15O4 2 ( H2 O) ]· 6H2 O[8,9] ,[As8V14 O4 2 ( H2 O) 1/2 ]4 - [10 ] ,[As8V14 O4 2 ( X) ]6 - [11] ( X=SO2 - 3,SO2 - 4,H2 O) .为了探究水热条件下 As- V- O体系的反应特性 ,我们开展了这方面的研究工作 ,并取得了突破性进展 .本文采用中温水热技术合成了含有机基团...

二苯基-15-冠-5加速钠离子和钾离子在微米管支撑的微-水/1,2-二氯乙烷界面上的转移反应

玻璃微米管针尖可用于支撑微米级的水/1,2-二氯乙烷（W/DCE）界面,并用来研究二苯基-15-冠-5（DB15C5）加速钠离子和钾离子转移反应的机理和求算其络合物的稳定常数.在两种极限情况下,即水相中金属离子浓度远大于有机相中DB15C5的浓度（DB15C5扩散控制过程）和有机相中DB15C5的浓度远大于水相中金属离子浓度（金属离子扩散控制过程）,循环伏安研究表明,加速钠离子转移反应均发生1∶1（金属离子:载体）的界面络合转移过程,相应的一级络合常数分别为logβ1=8.97±0.05和logβ1=8.63±0.03.而对于加速钾离子转移反应,当 DB15C5扩散控制时发生的是一个1:2的界面络合转移过程,当钾离子扩散控制时,在电位窗内却观察到两个过程:一个较低电位的1∶2的界面络合转移过程和一个较高电位的1∶1界面络合转移过程.两种极限条件下所求算的钾离子和DB15C5的二级络合常数分别为logβ1=13.64±0.03和logβ2=11.34±0.24.

Synthesis and electrochemical characteristics of lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate

Four lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate were prepared and characterized by elemental analyses, LR, UV-Visible,H-1 NMR, XPS and molar conductance. The redox properties of the lutetium complex with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate in dichloromethane were studied by cyclic voltammetry.

人体血浆中15种超痕量稀土元素的电感耦合等离子体质谱法测定

本文用电感耦合等离子体质谱法测定了人体血浆中的稀土元素。在优化的条件下 ,以内标法测得的各种纯水溶液的检测限在 0 .7(Eu)～ 5 .4(Gd) ng·L- 1范围内。研究了 K,Na,Ca,Fe等基体元素对稀土测定的影响。以 In为内标元素补偿样品基体效应以及灵敏度飘移。比较了直接稀释、HNO3- H2 O2 消解及 HNO3-HCl O4消解 3种样品处理方法 ,用 1% HNO3直接稀释样品可满足轻稀土元素的定量分析要求 ,方法的定量测定下限≤ 1μg·L- 1。

The crystal structure and supramolecular chain of [La(NO3)(3)(OH2)(2)(phen)]center dot 15-crown-5

[La(NO3)(3)(OH2)(2)(phen)]. 15-crown-5 is hexagonal, P6(5), with a = 10.955(2), c = 43.769(9) Angstrom, and D-calc = 1.668 g cm(-3) for Z = 6. In the complex, two nitrogen atoms (from phen) and eight oxygen atoms (six from three bidentate nitrate anions and two from water molecules) are coordinated to the central La(III) ion, forming a coordination polyhedron which is approximately a bicapped square antiprism. The coordinated water molecules donate hydrogen bonds to the oxygen atoms of the crown ether, forming polymeric hydrogen bonded chains which wrap helically along the unit cell direction c.

Miscibility, crystallization, and morphology studies of thermosetting polyimide PMR-15/PEK-C blends

Miscibility, crystallization, and mechanical properties of blends of thermosetting polyimide PMR-15 and phenolphthalein poly(ether ketone) (PEK-C) were examined. With the exception of the 90/10 blend, which has two glass transition peaks, all the blends with PMR-15 less than 90 wt % are miscible in the amorphous state according to DMA results. Addition of PEK-C hindered significantly the crystallization of PMR-15, indicating that there must exist some kind of interaction between molecular chains of PMR-15 and those of PEK-C. The semi-IPN system of PMR-15/PEK-C blends exhibits good toughness. Two distinct microphases, interweaving at the phase boundaries, were found in the PMR-15/PEK-C 60/40 blend. The toughness effect of the blends is discussed in terms of the interface adhesion between the two distinct phases and the domain sizes of the phases. The relation between miscibility and toughness of the blends was investigated. (C) 1996 John Wiley & Sons, Inc.

Preparation and crystal structures of LaCl3(15-crown-5) and [LaCl2(phen)(H2O)(2)(mu-Cl)](2)center dot(15-crown-5)center dot MeCN

LaCl3(15-crown-5), I was prepared by the reaction of LaCl(3)nH(2)O with 15-crown-5 and bipy (2,2'-bipyridyl). [LaCl2(phen)(H2O)(2)(mu-Cl)](2) .(15-crown-5). MeCN, II, was crystallized from a mixture of LaC1(3) . nH(2)O, phen (1,10-phenanthroline) and 15-crown-5 in MeOH/MeCN, Crystal structures of these two complexes have been determined by X-ray methods. The La(III) ion in I is coordinated by three Cl anions and five oxygen atoms of a crown ether. The two metal ions in II are bridged by two Cl anions and the crown ligand is hydrogen-bonded to the coordinated water molecules to form polymeric... crown/cation/cation/crown... chains.

15个乙烯-乙烯基化合物共聚物的取代基参数

本文应用取代基参数(SCS)方法处了15个EV共聚物的~(12)C NMR谱.它们是:(1)乙烯-α-烯烃共聚物,即乙烯-丙烯共聚物.乙烯-丁烯-1共聚物,乙烯-4-甲基-1-戊烯共聚物,乙烯-己烯-1共聚物和乙烯-辛烯-1共聚物;(2)乙烯-含氧乙烯基共聚物,即乙烯-甲基丙烯酸N,N-二甲基胺乙酯共聚物,乙烯-丙烯酸甲酯共聚物.乙烯-丙烯酸共聚物,乙烯-乙酸乙烯酯,乙烯-乙烯醇,乙烯-氧化碳共聚物(ECO)(?)乙烯-卤代乙烯共聚物及其它EV共聚物,即乙烯-氯化乙烯共聚物(包含氯化聚乙烯),乙烯-溴化乙烯共聚物,乙烯-苯乙烯共聚物(包含氢化丁二烯-苯乙烯共聚物)和乙烯-丙烯腈共聚物、得到了15种取代基的SCS参数.

稀土冠醚配合物的研究XX．Schiff碱型双冠醚N，N’－对苯二甲亚基双（4’－氨基苯并－15－冠－5）稀土配合物的合成和性质

合成了一种Ｓｃｈｉｆｆ碱型双冠醚Ｎ，Ｎ’－对苯二甲亚基双（４’－氨基苯并－１５－冠－５）及其稀土硝酸盐的固体配合物，通过元素分析、摩尔电导、ＩＲ、ＵＶ、１ＨＮＭＲ和热分析等对其性质作了表征与比较。

STRUCTURE OF [LA(NO3)(3)(OH2)(2)(OHME)(BIPY)].15-CROWN-5

[La(NO3)(3)(OH2)(2)(OHMe)(bipy).15-crown-5 is monoclinic, P2(1)/n, with a = 11.239(6), b = 19.302(7), c = 14.458(8) Angstrom, beta = 92.47(5)degrees, and D-calc = 1.63 g cm(-3) for Z = 4. In the complex, two nitrogen atoms (from bipy) and nine oxygen atom

5，10，15，20－四（对－山嵛酸乙酯－α－氧代苯基）卟啉LB膜结构研究

５，１０，１５，２０－四（对－山嵛酸乙酯－α－氧代苯基）卟啉ＬＢ膜结构研究王海水，曾广赋，谷淑珍，席时权（中国科学院长春应用化学研究所长春１３００２２）利用ＬＢ膜技术将分子组装成有序的分子单层或多层体系，研究膜内分子间相互作用和分子的结构，对了解结构...

5,10,15,20-四(对-乙酯苯基)卟啉LB膜的结构

对卟啉类化合物LB膜的结构、电性质和气敏性的研究已见报道。本文利用膜天平和UV-Vis分光光度计研究了标题化合物在气-液界面上的成膜特性、分子间相互作用和LB膜的结构。5,10,15,20-四(对-乙酯苯基)卟啉(TPEPP)由5,10,15,20-四(对-氰苯基)卟啉和乙醇酯化得到。元素分析测定值与计算值相符。λ(CHCl_3,nm):421,515,550,590,645;ν(KBr压