A Photophysical Study of Terphenyl Core Oligosulfonimide Dendrimers Exhibiting High Steady‐State Anisotropy

The photophysical properties of three dendrimers containing a p‐terphenyl core with appended sulfonimide branches of different size and n‐octyl chains have been investigated in dichloromethane solution. In the dendrimer absorption spectra contributions from both the branches and the core are clearly identified. The fluorescence spectra show only the characteristic fluorescence of the terphenyl unit. Energy transfer from the appended chromophoric groups to the core does not occur. In the dendrimers, the terphenyl core exhibits a very high fluorescence quantum yield (ca. 0.75) and a short emission lifetime (0.8 ns). These properties allowed investigations of the fluorescence depolarization caused by rotation of the dendrimers. The dendrimers show a very high steady‐state anisotropy in dichloromethane solution at room temperature (0.24 for the largest one), compared to that of the parent terphenyl under the same experimental conditions (<0.01) and in rigid matrix (0.33). Both the n‐octyl chains and the sulfonimide branches play important roles to slow down the molecular rotation.     

Synthesis, structures and spectroelectrochemistry of methyl-substituted bis(η-indenyl)iron(II) complexes

Several new methyl-substituted indenyl ferrocenes were prepared by metathesis reactions of the indenide (generated from the appropriate indene with BuLi) with ferrous chloride. The indenides used to prepare new ferrocenes were: 2-methyl-, 1,2-dimethyl-, 4,7-dimethyl-, 1,4,7-trimethyl-, and 1,3,4,7-tetramethyl-indenide. These indenyl ferrocenes, along with those prepared from indenide, 1-methylindenide, and 1,3-dimethylindenide, were then characterized by ¹H and ¹³C NMR, UV/visible spectroscopy, cyclic voltammetry and mass spectrometry. The cyclic voltammetry showed an additive relationship between oxidation potential and the number of methyl groups which is also position-dependent, whereas the UV/visible spectra showed two absorptions essentially unaffected by methyl substitution. Additionally, bis(2-methylindenyl)iron(II) and bis(4,7-dimethylindenyl)iron(II) were characterized by X-ray crystallography.     

气相毛细管柱切割-反吹技术及归一化法分析汽油中的芳烃(英文)

 发展了一种采用毛细管气相柱切割 反吹技术分析汽油中芳烃的方法。利用强极性毛细管预柱将芳烃保留至n C10 的脂肪族化合物之后 ,并将其反吹到非极性毛细管柱中按沸点详细分离分析。该方法使预柱先流出的组分和分析柱流出的组分通过一个微型三通进入同一检测器中 ,因此可用归一化方法定量分析汽油中的芳烃。该方法可在 15min内完成汽油中苯至C10 芳烃的分析 ,结果的相对标准偏差 (RSD)≤ 3% ,切割误差为± 5s时分析结果的RSD≤ 4 %。     

Influence of the activation temperature on structural and textural properties of NiMo/Al2O3 hydrodesulfurization catalysts

Investigations of a commercial NiMo/Al₂O₃ hydrodesulfurization (HDS) catalyst are directed towards optimization of the activation procedure of HDS catalyst concerning active phase formation and thermal stability. Structural and textural data obtained with XRD, IR-FTIR, XPS and LTNA reveal that the optimal temperature for the formation of active species on the catalyst surface and an appropriate pore structure is 300°C.     

Separating Ag, B, Cd, Dy, Eu, and Sm in a Gd matrix using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester extraction chromatography for ICP-AES analysis

The separation procedure for Ag, B, Cd, Dy, Eu and Sm as impurities in Gd matrix using ICP-AES technique with an extraction chromatographic column has been developed. The spectral interference of the Gd matrix on the elements was eliminated using a chromatography technique with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) as the mobile phase and XAD-16 resin as the stationary phase. Ag⁺, B₄O₇²⁻, and Cd²⁺ were eluted with 0.1 M HNO₃, while rare earth ions were not. The best eluent for separating Eu and Sm in the Gd matrix was 0.3 M HNO₃. The limit of quantitation for these elements was 0.6-3.0 ng mL⁻¹. The recovery of Ag, B, and Cd was 90-104% using 0.1 M HNO₃ as the eluent, while that of Eu, Gd, and Sm ranged from 100 to 102% with 0.3 M HNO₃. Dy was recovered quantitatively with 4 M HNO₃. The relative standard deviation of the methods for a set of three replicates was between 1.0 and 15.4% for the synthetic and standard Gd solutions. The proposed separation procedure was used to measure Ag, B, Cd, Dy, Eu, and Sm in a standard Gd solution.     

在离子液体中一步法合成吡唑[5,4-b]-γ-吡喃衍生物

芳醛、丙二腈与4,5-二氢-3-甲基-5-氧代-1-苯基吡唑在离子液体[bmim][BF₄]中反应, 合成了2-氨基-4-芳基-3-氰基-5-甲基-7-苯基吡唑[5,4-b]-γ-吡喃衍生物, 该法快速、高效, 是一种洁净的合成方法. 产物的结构通过红外光谱、核磁共振氢谱和元素分析进行表征.     

超高效液相色谱-串联质谱法快速同时测定生姜中10种营养成分

建立了超高效液相色谱-串联质谱（UHPLC-MS/MS）快速同时测定生姜中姜辣素类和姜黄素类营养成分的分析方法，具体包括6-姜酚、8-姜酚、10-姜酚、6-姜烯酚、8-姜烯酚、10-姜烯酚、四氢姜黄素、姜黄素、去甲氧基姜黄素、双去甲氧基姜黄素10种目标物。采用ZORBAX RRHD Eclipse Plus C18色谱柱（100 mm×2.1 mm，1.8 μm）分离，以0.1%（v/v）甲酸水溶液和0.1%（v/v）甲酸甲醇溶液为流动相进行梯度洗脱，采用电喷雾电离（ESI）源、正离子和多反应监测（MRM）模式对目标物进行定性确证和定量分析。10种营养成分的线性相关系数（r）均≥ 0.9995，方法的定量限为0.10~7.71 μg/L，样品基质在3个水平下的平均加标回收率为82.8%~115.3%，相对标准偏差（RSD）为0.58%~11.49%。分析结果显示，生姜中10种营养成分均有检出，其中6-姜酚的含量最高且集中分布于373.35~702.48 mg/kg。该法简便快速，准确可靠，适用于生姜中姜辣素类和姜黄素类营养成分的分析，可为生姜质量鉴定和控制提供技术手段。     

The role of TLC in the screening of inherited metabolic diseases

Summary Thin-layer chromatography (TLC) is a rapid, reliable and inexpensive screening technique for diagnosis of inherited metabolic diseases (IMD). Our screening program encompasses five main situations where the use of TLC is considered to be vindicated: (i) analysis of amino acids; (ii) screening for sugar defects; (iii) detection of pathological oligosaccharidurias; (iv) screening for organic acid disorders; and (v) detection of abnormalities in tryptophan metabolism. Examples are presented of chromatograms obtained from pathological samples. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Solubility enhancement of triflumizole by host-guest interaction with β-cyclodextrin

Summary The solubility enhancement of triflumizole, a systemic fungicide, by -cyclodextrin inclusion complexation was investigated by electron absorption spectroscopy. The respective association constant determined by different methods was estimated to 470±20M ^–1 in aqueous solution. A model for the host-guest complexation was deduced by molecular calculations.

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Löslichkeitsverbesserung von Triflumizole durchHost-Guest-Complexierung mit -Cyclodextrin

Zusammenfassung Die Löslichkeitsverbesserung des systemischen Fungizids Triflumizole durch Komplexierung mit -Cyclodextrin wurde mittels Elektronenabsorptionsspektroskopie untersucht. Die entsprechende Stabilitätskonstante wurde durch verschiedene Methoden erfaßt und betrug im wäßrigen Medium 470±20M ^–1. Ein Model für denHost-Guest-Complex wurde durch Molekülrechnungen erstellt.

     

Capillary electrophoresis as an alternative to HPLC for determination of honey flavonoids

Summary The general objective is to provide an alternative methodology based on capillary electrophoresis (CE) to characterize flavonoids from honey and hence determine its botanical origin. The specific objective is to compare the separation of flavonoids by CE with those achieved by HPLC to assess CE as an alternative technique for the determination of honey flavonoids. Fourteen different flavonoids isolated from honey were analysed by MECC and compared to the HPLC separations. It was difficult to find specific experimental conditions to separate all the flavonoids from honey in a single MEKC run. Three chromatographic conditions are optimized and, depending on the flavonoid markers sought in honey, the appropriate detection method should be chosen. Compared to the HPLC results, it is clear that CE could be an alternative technique in honey flavonoids analysis and particularly in the study of its geographical and floral origin.