聚乙烯醇存在下孔雀绿与[PtX_2(SnX_3)_2]~(2-)缔合显色反应的研究与应用

碱性染料阳离子与铂族金属络阴离子形成显色离子缔合物的反应,应用于铂族金属的萃取光度和浮选光度法测定已有一些文献报导。文献的研究表明,在过量卤离子(X~-)存在下的氢卤酸介质中,卤化亚锡与铂形成〔PtX_2(SnX_3)_2〕~(2-)络阴离子,Marczenko采用结晶紫(CV~+)阳离子与〔PtCl_2(SnCl_3)2〕~(2-)络阴离子形成离子缔合物用苯浮选,沉淀溶于乙醇后作光度测定铂,摩尔吸光系数可达2×10~5l·mol~(-1)·cm~(-1)。文献采用明胶使此类难溶于水的离子缔合物胶束增溶,在溶液中直接光度测定铂族     

金属材料分析方法的选择和施行——第四讲 金属材料中钛的测定（续）

2.6　钛的光度分析及显色试剂光度分析法在金属材料钛的测定中占有很重要的地位,而随着有机显色剂的研究和发展,可用于钛的光度测定的显色试剂也非常多。但能成功地应用于金属材料中光度测定钛的试剂却是屈指可数。主要的显色试剂有过氧化氢、二安替比啉甲烷和变色酸等。2.6.1　过氧化氢的性质及其与钛(Ⅳ)的显色反应纯过氧化氢是一种无色、有刺鼻嗅味、味涩且稍呈粘稠的液体。分子式为H2O2,相对分子质量为34.016,在20℃时的密度为1.43g·cm3,在压力为101.326kPa时沸点为152.1℃,凝固点为-0.43℃,此时凝结成四方晶体。它在4℃时的密度为1.…     

以钛-二安替吡啉甲烷-变色酸三元络合物的形式分光光度法测定钛

变色酸(XK)、二安替吡啉甲烷(дAM)是测定钛的两种重要试剂。近年来ганаго等研究了钛-二安替吡啉甲烷-溴代邻苯三酚红及钛-二安替吡啉甲烷-变色酸的形式分光光度法测定钛。我们对后者进行了研究,经试验发现显色液中有白色针状结晶析出。我们加入了乙醇防止了沉淀析出并对多种离子进行了干扰试验。实验证明本法是一个高选择性、精密度较好的快速分析法。     

罗丹明系列试剂与结晶紫系列试剂的区别

武汉大学等校编《分析化学》有这样一段叙述:“罗丹明B为三苯甲烷类碱性染料,遇SbCl_6生成紫色或蓝色不溶于水的离子缔合物。”这句话值得商榷。罗丹明是一类碱性染料,易溶于乙醇,如溶于水中则更易离解出带正电荷的离子,在分析化学中应用很广,可作为吸附指示剂,沉淀剂,显色剂及荧光试剂等。从分子结构看,它是氧杂     

基于Keggin阴离子链镍化合物的结构和质子导电性

由H+(H2O)2.5阳离子,[Ni(H2O)8]2+阳离子,[PW12O40]3-阴离子和异烟酸氮氧化物(HINO)自组装成一个具有质子导电性的化合物{[Ni(H2O)8][H(H2O)2.5](HINO)4(PW12O40)}n。293 K的单晶X-射线衍射分析表明标题化合物形成1个带有一维通道的三维氢键网络结构。[PW12O40]3-阴离子填充在一维通道内并且自组装成多阴离子链。热重分析表明在20~100℃范围内化合物没有失重,表明化合物结构单元内所有的水分子在100℃以下不易失去。标题化合物在85~100℃范围内表现出好的离子导电性(1×10-3~2×10-3S.cm-1)。     

单核Zn(Ⅱ)/Ni(Ⅱ)含氮配体配合物的合成、晶体结构及性质

合成了2个新的配合物[Zn(BPP)2(H2O)4](2,6-NDS)·0.5H2O(1)和[Ni(phen)2(H2O)2](A-2,5-DSA)·3H2O(2)(2,6-NDS=2,6-萘二磺酸根,A-2,5-DSA=苯氨-2,5-二磺酸根,BPP=1,3-二(4-吡啶基)丙烷,phen=1,10-邻菲咯啉),用X-射线单晶衍射结构分析方法测定了配合物的晶体结构。配合物1是单核分子,Zn2+离子与2个1,3-二(4-吡啶基)丙烷的2个N原子及4个水分子配位,形成单核配位阳离子。相邻配位阳离子通过配位水分子与氮原子的氢键作用联接成一维双螺旋阳离子链。双螺旋阳离子链与未配位的2,6-萘二磺酸根阴离子通过氢键作用形成二维超分子网。配合物2是单核分子,Ni2+离子与2个1,10-邻菲咯啉分子中的4个N原子及2个水分子配位,形成单核配位阳离子。配位阳离子与游离的水分子及苯氨-2,5-二磺酸根阴离子通过氢键作用构筑成二维超分子网。     

金属材料分析方法的选择和施行：第五讲 金属材料中钨的测定（续）

2.2钨的光度测定法用于测定钨的光度法甚多,特别是近年来许多新显色剂的研制成功,带来了数十种钨的光度测定新方法。但能作为较成熟的方法应用于钢铁等金属材料分析者仍较少。其原因主要在于共存元素干扰的消除问题尚未理想地解决。目前,在标准分析方法及一些日常分析的方法中用硫氰酸盐作为显色剂的钨的光度测定法占了主要地位,其中包括以钨(Ⅴ)与硫氰酸盐所形成的络阴离子与一些大分子的有机阳离子生成的离子缔合物的溶剂萃取光度法。2.2.1硫氰酸盐直接光度法测定钢中钨量[摘自《材料化学分析方法》第三次增补修改稿,上海材料研究所编印,1…     

钨钼杂多酸及其盐与二甲基亚砜加合物的制备和性质研究

在乙腈和水的混合溶剂中制备了9种钨钼杂多酸和杂多酸盐的二甲基亚砜加合物。研究结果表明,加合物中杂阴离子的Keggin结构基本不变。配体DMSO以S=O键上的氧作为配位原子,它不直接与杂阴离子骨架结构发生配位作用,而是与杂多酸中的质子氢或杂多酸盐中的金属阳离子以氢键或配位键相配位,生成的质子(钅羊)离子和金属配离子再通过离子缔合键与杂阴离子相结合,形成杂多酸或杂多酸盐加合物。     

硫氰酸锌络阴离子与亮绿在水相中的显色反应——分光光度法测定微量锌

硫氰酸锌络阴离子[Zn(SCN)4]~(2-)与某些三苯甲烷类碱性染料的水相显色反应已有报导,而与亮绿的水相反应迄今未见报导。文献认为[Zn(SCN)4]~(2-)与亮绿在水相反应前后无颜色变化。但实际上亮绿能在微酸性水溶液中与[Zn(SCN)4]~(2-)生成绿色缔合物,只因在微酸性介质中试剂亮绿本身的绿色很深,缔合物与亮绿的吸收峰基本重合,因而不能在水相用光度法直接测定锌。我们首先在低酸度下(0.03N硫酸介质)使亮绿与[Zn(SCN)4]~(2-)缔合,然后将酸度提高到0.26N,使过剩的亮绿在较强酸度下质子化,试剂空白绿色消褪、     

两个单核镍含氮配体配合物的合成、晶体结构及荧光性质(英文)

采用回流法在水溶剂中合成了2个含氮配体单核镍配合物[Ni(phen)2(H2O)2](1,6-nds)·2H2O(1)和[Ni(phen)3](1,6-nds)·10H2O(2)(1,6-nds=1,6-萘二磺酸根离子,phen=1,10-邻菲罗啉)。配合物1中,镍离子与2个1,10-邻菲罗啉和2个水分子配位,形成[Ni(phen)2(H2O)2]2+阳离子。2个没有配位的水分子通过氢键与[Ni(phen)2(H2O)2]2+和1,6-萘二磺酸根离子相互连接形成二维层状结构。配合物2中,镍离子与3个1,10-邻菲罗啉配位,形成[Ni(phen)3]2+阳离子。大量的氢键将自由的水分子和1,6-萘二磺酸根离子连接形成三维网状结构。2个配合物中1,6-萘二磺酸根离子均没有与镍离子配位,只是起到平衡电荷的作用。室温下,配合物显示了较大的荧光发射峰,其最大发射峰分别在443和438 nm。     

Generation and detection of levuglandins and isolevuglandins in vitro and in vivo

Levuglandins (LGs) and isolevuglandins (isoLGs), formed by rearrangement of endoperoxide intermediates generated through the cyclooxygenase and free radical induced oxidation of polyunsaturated fatty acids (PUFAs), are extraordinarily reactive, forming covalent adducts incorporating protein lysyl ε-amino groups. Because they accumulate, these adducts provide a dosimeter of oxidative injury. This review provides an updated and comprehensive overview of the generation of LG/isoLG in vitro and in vivo and the detection methods for the adducts of LG/isoLG and biological molecules in vivo.     

Enthalpies of solution of purine and adenine in water and in dimethylsulfoxide

Journal of Solution Chemistry - Enthalpies of solution of purine and adenine in water and in demethylsulfoxide were measured calorimetrically in the temperature range 25–40°C. ΔH s...     

Coassembly of Nanorods and Nanospheres in Suspensions and in Stratified Films

The entropically driven coassembly of nanorods (cellulose nanocrystals, CNCs) and nanospheres (dye‐labeled spherical latex nanoparticles, NPs) was studied in aqueous suspensions and in solid films. In mixed CNC‐latex suspensions, phase separation into an isotropic latex‐NP‐rich and a chiral nematic CNC‐rich phase took place; the latter contained a significant amount of latex NPs. Drying the mixed suspension resulted in CNC‐latex films with planar disordered layers of latex NPs, which alternated with chiral nematic CNC‐rich regions. In addition, fluorescent latex NPs were embedded in the chiral nematic domains. The stratified morphology of the films, together with a random distribution of latex NPs in the anisotropic phase, led to the films having close‐to‐uniform fluorescence, birefringence, and circular dichroism properties.     

Determination of diazepam and nordazepam in milk and plasma in the presence of oxazepam and temazepam

For studies on the excretion of drugs into milk a sensitive high-performance liquid chromatographic assay was developed to quantitate diazepam and nordazepam in the milk and plasma of humans and rabbits in the presence of their major metabolites, oxazepam and temazepam. Flurazepam was used as an internal standard. The assay involves extractions with diethyl ether and an additional acid clean-up step. Chromatographic separation was achieved by a LiChrospher 60 RP-select B (5 microns) column and KH2PO4- acetonitrile (69:31, v/v) adjusted to pH 2.80 as a mobile phase. The same extraction and chromatographic conditions were suited to both types of samples, milk and plasma. The limits of determination using ultraviolet detection at 241 nm was for diazepam 20 ng/ml and for nordazepam 15 ng/ml. The absolute recoveries of diazepam, nordazepam and flurazepam in human milk were 84, 86 and 92% and in human plasma 97, 89 and 94%, respectively. The within- and between-day accuracy and precision for diazepam and nordazepam in milk and plasma at all concentrations tested (20-1500 ng/ml) were better than 8%. The high fat content which occurs in rabbit milk presented no limitation for the extraction of lipophilic diazepam: the method was successfully used to monitor milk and plasma concentrations of diazepam and nordazepam in lactating New Zealand White rabbits during 26-h infusions of diazepam (1.4 mg/h).     

Comparison and correlation of in vitro, in vivo and in silico evaluations of alpha, beta and gamma cyclodextrin complexes of curcumin

In the present study investigated the effect of curcumin (CUR) alpha (α), beta (β) and gamma (γ) cyclodextrin (CD) complexes on its solubility and bioavailability. CUR the active principle of turmeric is a natural antioxidant agent with potent anti-inflammatory activity along with chemotherapeutic and chemopreventive properties. Poor solubility and poor oral bioavailability are the main reasons which preclude CUR use in therapy. Extent of complexation was β-CD complex (82 %) > γ-CD (71 %) > α-CD (65 %). Pulverization method resulted in significant enhancement of CUR (0.002 mg/ml) solubility with CUR α-CD complex (0.364 mg/ml) > CUR β-CD complex (0.186 mg/ml) > CUR γ-CD complex (0.068 mg/ml). Gibbs-free energy and in silico molecular docking studies favour formation of α-CD complex > β-CD complex > γ-CD complex. With reference to CUR, relative bioavailability of CUR α-CD, CUR β-CD and CUR γ-CD complexes were 460, 365 and 99 % respectively. CUR–CD complexes exhibited increased bioavailability with an increase in t_½, tmax, Cmax, AUC, Ka, and MRT; and a decrease in Ke, clearance and Vd values. AUC increase was CUR α-CD complex > CUR β-CD complex > CUR γ-CD complex. Significant difference (p < 0.05) was observed between CUR α-CD complex and CUR γ-CD complex by one-way ANOVA and Dunnett’s post hoc test for multiple comparison analysis. Correlation observed between in vitro, in vivo and in silico methods indicates potential of in silico and in vitro methods in CD selection.     

Electrochemical Fluorination of Benzamide and Acetanilide in Anhydrous HF and in Acetonitrile

Electrochemical fluorination of benzamide in anhydrous hydrogen fluoride does not involve the amide group but occurs exclusively at the aromatic ring, yielding isomeric fluoro- and difluorobenzamides and 3,3,6,6-tetrafluoro-1,4-cyclohexadienecarboxamide. Electrochemical fluorination of benzamide in acetonitrile as solvent gives the same products, as well as benzonitrile and its fluorinated derivatives and products of hydrolysis and fluorination of acetonitrile. Electrochemical fluorination of acetanilide in anhydrous HF leads to complete tarring of the reaction mixture, while its fluorination in acetonitrile results in selective formation of m-fluoroacetanilide.     

Structure of dimethoxyamine in the crystalline and gaseous phases and in solution

Conclusions It has been established by the methods of x-ray diffraction analysis and electron diffraction analysis and measurements of the dipole moments and the birefringence that in the crystalline and gaseous phases, as well as in solution, N,N-dimethoxyamine has a gauche-gauche conformation, which is stipulated by a stabilizing nO-N-O* orbital interaction. The geometric parameters of the molecule have been determined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2235–2242, October, 1986.