CTAB胶束微环境中BY增溶位置的探讨

本文用ＵＶ吸收光谱对（ＢＹ＝ＣＴＡＢ）体系胶束化过程中预胶束的形成，以及预胶束向胶束的转变过程进行了分析。采用Ｇｏｕｙ－Ｃｈａｐｍａｎ模型，建立了ＣＴＡＢ胶束微环境中ＢＹ表现解离常数与胶束结构参数之间的定量关系，根据水溶液和各种盐浓度条件下ＣＴＡＢ胶束溶液中酸碱解离常数的测量，分析了ＢＹ在ＣＴＡＢ胶束扩散层中的增溶位置，讨论了ＣＴＡＢ胶束对ＢＹ选择性吸附的特性。     

The matrix-isolation IR spectrum of the o-quinonoid intermediate in the photolysis of 2-nitrobenzyl methyl ether

Photolysis of 2-nitrobenzyl methyl ether in Ar and N₂ matrices at 12 K generated an intermediate with λ_max at 430 nm, and which was itself photolabile at 430–460 nm. Matrix IR spectra, as well as the UV-visible absorption, were obtained for this species. An analogous intermediate had previously been observed in flash-photolysis studies of 2-nitrobenzyl 4-cyanophenyl ether, and had been assigned an o-quinonoid structure on the basis of its kinetic behaviour and the position of its UV-visible absorption. In the matrix studies with 2-nitrobenzyl methyl ether, the IR spectra confirmed the o-quinonoid structure.     

4-氯查尔酮缩氨基硫脲微环境效应的紫外-可见光谱研究

合成了新化合物4-氯查尔酮缩氨基硫脲(CCT)并进行了表征;探讨了溶剂极性、溶液的酸度、β-CD及不同离子存在的微环境对CCT的紫外-可见吸收光谱的影响。     

Second Dissociation Constant of H<Subscript>2</Subscript>Te and the Absorption Spectra of HTe<Superscript>–</Superscript>, Te<Superscript>2–</Superscript> and Te<Subscript>2</Subscript><Superscript>2–</Superscript> in Aqueous Solution

We have measured the second acid dissociation constant, K _2a , at several ionic strengths for hydrogen telluride (H₂Te) using the Charge Transfer to Solvent (CTTS) uv spectra of its anions HTe⁻ and Te²⁻. Since it is produced in our solutions, we have also determined the spectra of Te₂ ²⁻ both in the uv and in the visible regions. At 25 ^∘C, K _2a = (1.28 ± 0.02) × 10⁻¹² by extrapolation to zero ionic strength. Its value at an ionic strength equal to 0.5 mol.dm^-3 was estimated to be (8.7 ± 0.2) × 10⁻¹². The solution thermodynamics of these species are also discussed and comparisons are made to related acids.     

掺杂阴离子对电化学合成的聚邻甲苯胺性质的影响

邻甲苯胺在酸性介质中的聚合速率与酸的种类有关,聚合速率影响了各种掺杂阴离子聚合物膜的形态,聚合物的电导率、循环伏安曲线形状受掺杂阴离子的影响,其电容量与掺杂阴离子的种类及形态有关,阴离子的种类对电极电位和紫外-可见光谱无影响。     

Molecular complexes of crown ethers. Part 3. Effect of cations on charge transfer complexes with TCNE

The intermolecular charge transfer complexes (CT) of two crown ethers (CE), viz, B15C5 and DB18C6 (as donors), and tetracyanoethylene (TCNE), as acceptor, were studied in the UV-visible region in dichloroethane (DCE), at 298.2 K. The sequence of addition of the cation was varied in the case of B15C5 such that in one system the sequence was (CE+Cation)+TCNE and in the other (CE+TCNE)+cation. These two systems were found to be non-interchangeable, even under reflux conditions, giving differentK _c values which were explained as being due to the different geometries of the CE. For the first sequence, the values most affected depended on the fit of the metal cation with the ether cavity, thus in B15C5, Na⁺ showed the greatest effect, while for DB18C6 it was K⁺.     

Induced Electronic and Thermal Effects of 86 MeV Nickel Ions in Bisphenol-A Polycarbonate

Bisphenol-A polycarbonate films were irradiated with 86 MeV swift heavy nickel ions at varying fluences, ranging from 1 × 10¹¹ to 1 × 10¹³ ions cm^?2, under vacuum at room temperature, to analyze the induced electrical and thermal modifications. AC conductivity measurements and UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques were applied to analyze the changes. A significant, exponential increase in conductivity at higher frequency was observed with the increase of nickel ion fluence. UV-visible analysis corroborated the results of the AC conductivity measurement, revealing the increase in size of the carbon clusters embedded in the polymer network, with the increase of heavy ion fluence. FTIR analysis revealed the formation of alkene and alkyne end groups at higher doses, which further supported the suggestion that the variation in electrical properties induced by the ion irradiation of the polymer was due to development of a carbonaceous phase inside the polymer due to the irradiation. Thermal analysis, i.e., TGA and DSC patterns, showed that chain-scission was the leading phenomena in the heavy ion-irradiated polycarbonate samples, resulting in degradation of their thermal stability.     

Synthesis,Spectral, and Structural Characterization of Bisthiocarbohydrazone Derivatives

Abstract

Bisthiocarbohydrazone derivatives of three heterocyclic ketone ligands, having a flexible coordination ability; 1, 5-bis (2-acetylthiophene) thiocarbohydrazone; 1, 5-bis (2-acetylfuran) thiocarbohydrazone; and 1, 5-bis (2-acetylpyrrole) thiocarbohydrazone were synthesized and characterized by elemental analysis, UV-visible, FT-IR, cyclic voltammetry, and ¹H and ¹³C-NMR spectral studies. All bisthiocarbohydrazone exhibited the thioketone—thioenol tautomeric forms, as evidenced by IR spectral data and single crystal X-ray diffraction studies of 1, 5-bis (2-acetylfuran) thiocarbohydrazone and 1, 5–bis (2-acetylpyrrole) thiocarbohydrazone.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.     

Macrocyclic 14-Membered Ring Diketal Dilactams: Evaluation of their Divalent Cation Binding Properties

The binding abilities of a new class of 14-membered ring ligands bearing diketal dilactam functions were explored by UV-visible spectrophotometry. Their formation constants, determined in THF solution, showed appreciable complexation with divalent cations (stability order: Sr²⁺≥Ca²⁺>Zn²⁺≥Mg²⁺>Ba²⁺) whereas no association was observed with monovalent cations. The stoichiometry of the complexes formed was essentially 1:1 although sometimes a low percentage (<10%) of 1:2 (cation–ligand) species was detected. The corresponding formation constants determined by computation (STAR program) were in the range 1.5<log?β ¹¹<4.8 and 4.4<log?β ¹²<7.1. They depend significantly on the nature of the substituents. In addition, solvent extractions carried out in a water–chloroform system showed the highest constants (log K ^ex) for the most substituted macrocycles 7b and 7c (norephedrine series) with a lipophilic skeleton.     

Cloud point extraction of aluminum (III) in water samples and determination by electrothermal atomic absorption spectrometry,flame atomic absorption spectrometry and UV-visible spectrophotometry

Cloud point extraction was applied as a preconcentration step for the determination of trace level of Al(III) in water samples with electrothermal atomic absorption spectrometry (ETAAS), flame atomic absorption spectrometry (FAAS) and UV-visible spectrophotometry. The aluminum was extracted as aluminum-Eriochrome Cyanine R (ECR) complex, at pH 6 by micelles of the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). The investigations showed that the same CPE procedure can be used for different detection techniques. The results obtained from these techniques were evaluated. Under the optimal conditions, limit of detection obtained with ETAAS, FAAS and UV-visible spectrophotometry were 0.03 ng mL^?1, 0.06 µg mL^?1 and 0.01 µg mL^?1, respectively. The accuracy of the procedure was tested by analysing certified reference material. The method was successfully applied to determination of aluminum in water samples and dialysis fluid.