稀土萘乙酸邻菲绕啉三元配合物的合成和表征

合成了6种稀土(RE)-萘乙酸(NAA)-邻菲绕啉(Phen)固体配合物,其通式为RE(NAA)_3·Phen(RE=Y,La,Nd,Sm,Eu,Er)。通过元素分析,摩尔电导,IR,UV-Vis,H-NMR,XPS和TG-DTA分析,研究了配合物组成、性质及稀土离子与配体间的成键特性。     

Interaction of Hydroxylamine with Esters of 2-Oxobutenoic Acids. Synthesis of 1-Hydroxy-3-hydroximino-2-pyrrolidinones

New 3-hydroximino-1-hydroxy-2-pyrrolidinones have been synthesized by the interaction of NH₂OH and NH₂OBn with the methyl esters of 2-oxo-3-butenoic acid derivatives. Some intermediate compounds have been isolated and identified and the reaction mechanism is discussed.     

Thermodynamic Study of the Three Isomers of Bromobenzoic Acid

The enthalpies of sublimation and fusion and triple-point temperatures of 2-bromo-. 3-bro-mo- and 4-bromobenzoic acids have been determined precisely by sublimation calorimetry, drop calorimetry and differential thermal analysis. The measurements of sublimation enthalpy of the three acids were made at 333, 348 and 363 K, respectively, using a Tian-Calvet microcalorimeter equipped with Knudsen effusion cells. The derived standard molar enthalpies of sublimation at 298.15 K are (95. 94±0. 41), (99. 20± 0.18), and (103. 08±0. 59) kJ · mol-1for the 2-bromo-, 3-bromo- and 4-bromobenzoic acids, respectively. In addition, the saturated vapour pressure of these compounds was also calculated on the basis of the sublimation experiments. The enthalpy of fusion, the triple-point temperatures and the mole fraction purities of the samples of the investigated substances were measured using the mean temperature version DTA apparatus developed by the CTM of the CNRS in Marseille. The triple-point temperature and the     

平行双铂丝微电极用于铁氰化钾电流滴定法测定抗坏血酸的研究

平行双柱微电极是一种基于可逆氧化还原物质在电极间反馈扩散使得信噪比进一步增大的新型微电极,作者首次将这种电极应用于电流滴定分析中。结果显示,电极间距很小时,终点突跃变敏锐,使灵敏度进一步提高。该方法不需搅拌溶液,单次测量样品量只需约3μ1,是一种有实用价值的新方法。     

Silicate Xerogels with Dopant-Induced Chirality

A series of silicate xerogels with entrapped chiral amino acids have been obtained via sol-gel technology. The transparent, glassy samples obtained exhibit chirality in the bulk due to the presence of the entrapped asymmetric molecules. Measurements of the optical activity of the doped xerogel samples revealed that the entrapment did not significantly influence the optical activity observed for liquid solutions of the amino acids. Thus, the sol-gel method enables the preparation of amorphous optical materials exhibiting properties of strictly spatially defined molecular systems. Apart from the obvious optical applications, such porous materials with asymmetric centers might find interesting applications in chiral chemical syntheses and separations.     

Electrogenerated Chemiluminescence Based on Tris(2,2′-bipyridyl) Ruthenium(II) with Hydroxyl Carboxylic Acid

Upon the electrochemical oxidation of tris(2,2′-bipyridyl) ruthenium(II) [Ru(bpy)²⁺₃] and hydroxyl carboxylic acids, for instance, citric acid, tartaric acid, malic acid, and -gluconic acid, bright electrochemiluminescences (ECLs) were observed. Different luminescent reactions were presented depending on the applied potential. The light emission was mainly caused by the reaction between alkoxide radical ion and Ru(bpy)³⁺₃below the potential +1.80 V (vs Ag/AgCl). The luminescence intensity obviously increased because of the more complex reaction process. The luminescence wavelength of 608 nm, which could be found either at higher potential than +1.80 V or in the potential range from +1.30 to +1.80 V, confirmed that ECL was caused by Ru(bpy)²⁺₃*. The factors which affect the determination and HPLC separation of the four acids were also investigated.     

Pictet-Spengler reactions catalyzed by Brønsted acid-surfactant-combined catalyst in water or aqueous media

Perfluorooctanesulfonic acid (PFOSA), Brønsted acid-surfactant-combined catalyst, efficiently catalyzes the Pictet-Spengler reactions of β-arylethyl carbamate derivatives with aldehydes in water. The present reaction is accelerated by the addition of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP).     

Determination of TNT and its metabolites in water samples by voltammetric techniques

Square-wave voltammetry with the hanging drop mercury electrode as the working electrode was used for the determination of ultratraces of explosives in aqueous solution. It was shown that the strong pressure dependence of the pneumatically controlled multimode electrode system of a conventional Metrohm apparatus could be compensated by an additional pressure regulation, through which the pressure variations could be decreased when switching from deaeration to the static measurements. By using square-wave voltammetry with this electrode system after this modification the limits of detection for 2,4,6-trinitrotoluene (TNT) and other TNT-metabolites could be decreased down to 0.2 μg L⁻¹ when using a measurement time of 6 min. Also a simultaneous determination of TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was shown to be possible over a wide linear range and the detection limits then were 2.2 μg L⁻¹ for TNT and 25 μg L⁻¹ for RDX. By applying the highly stable and adjustable pressure as mentioned before, the calibrations could be kept stable over a period of up to 1 week.     

Crystal Structures of 1,5,9,18,22,26-Hexaaza[11.11]-p-cyclophane Adducts; Two-dimensional Supramolecular Networks

Two newly identified supramolecular structures arise from self-assembly of the macrocyclic 1,5,9,18,22,26- hexaaza[11.11]-p-cyclophane salts with o-nitrophenol (C₂₈H₅₀N₆)⁴⁺·4(C₆H₄NO₂O)⁻ (1) and with HCl (C₂₈H₅₂N₆)⁶⁺·6Cl^-·4H₂O (2). In both cases two-dimensional supramolecular sheets are formed.     

混合配体、希土三元配合物的研究 Ⅳ.3,5—二硝基水扬酸(H_2DNSA)、邻菲咯啉(phen)、希土(RE)三元固体配合物的合成及性质

本文报道了十种希土元素与3,5-二硝基水扬酸、邻菲咯啉三元配合物的制备方法。通过元素和化学分析测定了化合物的化学组成,并用红外光谱、紫外光谱、差热分析、磁化率、X射线粉天衍射等对所合成的化合物进行了结构和性质的研究。