叠氮二乙基铝三聚体和单体的缔合-解离平衡的研究

尽管叠氮二乙基铝Et₂AlN₃(DEAA)是一个重要的化合物,但人们对它研究还是很少的。本文通过温度-蒸气压关系研究了纯态DEAA的三聚体和单量体之间的缔合-解离平衡;通过相对分子质量测定、核磁共振氢谱和核磁共振铝谱的测定,研究了在苯和甲苯溶液中DEAA的三聚体和单量体之间的缔合-解离平衡。借助温度-蒸气压曲线分别计算了DEAA三聚体和单量体的气化焓和解离焓;通过相对分子质量测定、核磁共振铝谱测定等方法计算得到了溶液中DEAA三聚体和单量体的解离平衡常数、解离焓和解离熵等热力学数据。     

聚吲哚及其衍生物的荧光光谱

在三氟化硼乙醚及其混合电解质中,吲哚及其衍生物阳极氧化可以获得高质量的聚吲哚及其衍生物膜:聚吲哚、聚(5-甲基吲哚)、聚(5-硝基吲哚)、聚(5-氰基吲哚)、聚(5-溴吲哚).它们可溶于DMSO和THF中.聚吲哚及其衍生物具有良好的荧光性质;单体的发射光谱与取代基有关,而聚合物的发射光谱几乎不受取代基的影响.电子离域程度增大,使得聚合物的激发和发射光谱红移,宽的分子量分布则会使聚合物的激发和发射光谱变宽.     

9,10-二氢化菲在三氟化硼乙醚-浓硫酸混酸中的电化学聚合

在三氟化硼乙醚(BFEE)-浓硫酸混合电解质体系中直接氧化9,10-二氢化菲获得了高质量聚(9,10-二氢化菲)膜, 其电导率为3.8×10－1 S/cm. 9,10-二氢化菲在BFEE＋10%浓硫酸体系中的起始氧化电位为0.93 V vs. SCE, 远低于其在乙腈＋0.1 mol/L Bu4NBF4溶液中的起始氧化电位(1.75 V vs. SCE). 在BFEE＋10%浓硫酸体系中获得的聚(9,10-二氢化菲)膜具有良好的电化学性质. 聚合物部分溶于二甲基亚砜、四氢呋喃、氯仿等极性溶剂. FT-IR和量化计算表明聚合反应主要发生在2, 7位或者3, 6位. 荧光光谱和热重分析表明聚合物是一种良好的蓝色荧光材料且具有良好的热稳定性.     

Efficient dehydrogenation of 1,2,3,4-tetrahydroquinolines mediated by dialkyl azodicarboxylates

Various dialkyl azodicarboxylates were investigated for the dehydrogenation of 1,2,3,4-tetrahydroquinolines to quinolines. The dehydrogenation rates varied according to the electronic and steric nature of the used dialkyl azodicarboxylates. Among solvents screened with diethyl azodicarboxylate, chloroform exhibited superior results to others. A variety of 1,2,3,4-tetrahydroquinolines underwent the present dehydrogenation to produce the corresponding quinolines. Diethyl hydrazodicarboxylate, which is a reduced species of diethyl azodicarboxylate, was easily separated for recycle.     

Low‐potential facile electrosynthesis of free‐standing poly(1H‐benzo[g]indole) film as a yellow‐light‐emitter

High‐quality free‐standing poly(1H‐benzo[g]indole) (PBIn) films were synthesized electrochemically by direct anodic oxidation of 1H‐benzo[g]indole (BIn) in boron trifluoride diethyl etherate. PBIn films obtained from this medium showed good electrochemical behavior and better thermal stability with a conductivity of 0.29 S cm^?1. PBIn films with low band gap value (1.59 eV) were insoluble in acetone and tetrahydrofuran. The structure and morphology of the polymer were studied by UV–vis, FTIR, and scanning electron microscopy, respectively. The results of quantum chemistry calculations and the spectroscopies of dedoped PBIn indicate that the polymerization of BIn mainly occurs via C₍₂₎ and C₍₅₎ position. The polymer film was compact with regular nanoparticles on the surface. Fluorescent spectral studies indicate that solid‐state PBIn film is a good yellow‐light‐emitter. Thermal stability of PBIn film is higher than poly(indole‐6‐carboxylic acid), poly(5‐formylindole), and polyindole. To the best of our knowledge, this is the first report on the electrosynthesis of free‐standing polyindole derivatives as yellow‐light‐emitter. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2730–2738     

Lanthanum nitrate as an efficient and recoverable homogeneous catalyst for the transesterification of dimethyl carbonate with ethanol

Lanthanum nitrate was an efficient and recoverable homogeneous catalyst for the transesterification of dimethyl carbonate (DMC) with ethanol. It was reused 5 times for the transesterification without loss of its catalytic activity.     

Novel and efficient aqueous phase synthesis of N-substituted azepines via tandem Michael addition and cyclization in the presence of β-cyclodextrin

N-substituted azepines were synthesized for the first time in water under neutral conditions by the reaction of aromatic amines, dimethyl/diethyl acetylene dicarboxylate, 2,5-dimethoxytetrahydrofuran mediated by β-cyclodextrin in high yields. β-Cyclodextrin can be recovered and reused with just a small loss of catalytic activity.     

On-line solid phase extraction-liquid chromatography–mass spectrometry for trace determination of nerve agent degradation products in water samples

Three primary nerve agent degradation products (ethyl-, isopropyl- and pinacolyl methylphosphonic acid) have been determined in water samples using on-line solid phase extraction-liquid chromatography and mass spectrometry (SPE-LC–MS) with electrospray ionisation. Porous graphitic carbon was employed for analyte enrichment followed by hydrophilic interaction chromatography. Diethylphosphate was applied as internal standard for quantitative determination of the alkyl methylphosphonic acids (AMPAs). By treating the samples with strong cation-exhange columns on Ba, Ag and H form, the major inorganic anions in water were removed by precipitation prior to the SPE-LC–MS determination. The AMPAs could be determined in tap water with limits of detection of 0.01–0.07 μg L⁻¹ with the [M−H]⁻ ions extracted at an accuracy of ±5 mDa. The within and between assay precisions at analyte concentrations of 5 μg L⁻¹ were 2–3%, and 5–9% relative standard deviation, respectively. The developed method was employed for determination of the AMPAs in three natural waters and a simulated waste water sample, spiked at 5 μg L⁻¹. Recoveries of ethyl-, isopropyl- and pinacolyl methylphosphonic acid were 80–91%, 92–103% and 99–106%, respectively, proving the applicability of the technique for natural waters of various origins.     

Convenient and Regioselective One‐Pot Solvent‐Free Synthesis of ß‐Hydroxyphosphonates

A simple, efficient, regioselective, and solvent‐free method has been developed for the synthesis of β‐hydroxyphosphonates from epoxides and triethyl phosphite using ZnCl₂ in high yields under mild conditions.     

Malonic Ester Amide Synthesis: An Efficient Methodology for Synthesis of Amides

A general methodology “malonic ester amide synthesis” has been demonstrated, which uses α-substituted/unsubstituted diethyl malonates for the decarboxylative acylation of various aromatic/heteroaromatic primary/secondary amines to form one-carbon homologated amides, thus providing easy access to amides with odd/even chain lengths and an array of substituents on the alkyl/aryl part while avoiding use of acyl chlorides or peptide coupling reagents.

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