稀土金属有机化学的最新进展

综述了我们近年来在稀土金属有机化合物的合成,结构以及它们在有机合成和极性单体聚合中的应用的新进展。     

金属有机化合物中过渡金属的原子吸收分光光度法测定

本文报导应用火焰原子吸收分光光度法对金属有机化合物中过渡金属铜、镍、钴、铁、钼及铬的定量测定。我们将金属有机化合物溶解在适当的有机溶剂或水中,不必分离基体,即可用标准加入法直接进行测定。操作简单,速度快,相对误差<0.4％。     

有机金属化合物的电子计数法和结构规则

本文将有机金属化合物的价电子计数法划分为两类,即中性配位体法和封闭壳层配位体法。将(9N-L)结构规则修改为(9N-L+p)规则,并稍加推广,可适用于有机化合物、有机金属化合物、各类原子簇(包括多核有机金属化合物)、硼烷及多层夹心化合物等。     

介绍一种金属有机化合物的分类新方法: 共价键分类法

本文比较详细地介绍了M.L.H.Green最近提出的金属有机化合物分类新方法-共价键分类法，包括基本概念、MLX丰度图的绘制及其在提供金属的反应性与反应机理等信息方面的应用。     

用于可充电器件的有机电极材料

有机化合物作为可充电器件的电极材料可以通过自身电活性部位电荷状态的变化来实现本征的氧化还原反应.除了锂离子电池外,有机电极材料还可以用于其他离子半径更大的金属离子电池(如Na+、K+、Mg2+、Zn2+等).有机电极材料还具有诸多优势,比如结构多样、成本低廉、资源丰富和可持续性高,易于通过适当的材料设计调整其性能等,已...     

含氟芳杂环化合物

一、引言含氟芳杂环化合物是氟化学中一个很有发展潜力的研究领域。由于氟原子和氢原子有相似的原子半径、所以将氟引入到有生物活性的有机化合物中,通常不需改变这些化合物的构型和构象,就能满足受物酶的空间要求,即所谓等几何图形效应(isogeometric     

单柱离子色谱的研究-有机化合物中氯,溴元素的微量分析

本文介绍用单柱离子色谱法对有机化合物中氯和溴进行微量分析。样品经氧瓶法燃烧分解,被吸收于含双氧水的苯二甲酸氢钾溶液中的Cl-和Br-,可在单柱离子色谱的分离柱上得到分离,然后用电导检测器检测,用峰面积积分进行定量。本法简便、快速,可同时测定氯、溴两种元素。分析标准偏差分别为±0.39%和±0.59%。     

电荷转移络合物理论在有机化学中的作用

本文综述了电荷转移络合物理论在有机化学方面的应用，其中包括在有机化学反应机理的研究，有机化合物的分析分离和高分子聚合反应机理等几个方面的应用。     

异戊烯金属有机化合物与羰基化合物加成的区域选择性研究进展

异戊烯金属有机化合物与羰基化合物加成反应是合成含α-羟基异戊烯结构单元的天然化合物最简便的方法,但该反应通常生成α-加成和γ-加成两种异构体。不同金属对反应的区域选择性有很大影响。本文综述了异戊烯金属有机化合物与羰基化合物加成反应的区域选择性及其在天然产物合成中的应用。     

分装金属有机化合物晶体的保护技术

X-射线衍射晶体结构的分析是确定化合物结构的常用方法之一。对空气敏感的化合物通常采用装毛细管的方法进行。文献上曾有关于金属有机化合物进行X-射线衍射晶体结构分析结果的报道,但保护技术并无详细记载。我们认为,对微量氧和水份十分敏感的化合物进行X-射线结构分析时,如何将大小约为100μm~3晶体试样在惰性气体保护下封入薄壁毛细管是问题的关键。黄吉玲曾介绍了西德马普学会煤炭研究所建立的“裤形管”分装技术,分装对空气敏感的化合物。但对空气和湿度都敏感的化合物,则要在低温操作箱中进行。     

吹扫捕集-气相色谱/质谱法分析汉江有机污染物

采用恒温水浴吹扫捕集-气相色谱/质谱(P&T-GC/MS)法分析汉江水中挥发性有机物,提高了挥发性有机物分析的灵敏度;选用低空白的纯净水,降低了分析的干扰。采用避光的方法以及将水样直接过柱,提高了半挥发性有机物的回收率。用改进了的方法分析汉江水共检出有机物36种。此方法同样适用于其它地表水中有机物的分析。     

具有生理活性的天然有机化合物

本文从天然药物、天然农药、生长及生态调节物质、精神依赖药物和全合成等几个方面, 通过评论一些有较大社会意义或学术价值的化合物, 试图透视具有生理活性天然有机化合物这一常盛不衰的热点研究领域的发展脉络, 及对人类生活的意义。     

Analysis of volatile organic compounds in indoor environments using thermal desorption with comprehensive two‐dimensional gas chromatography and high‐resolution time‐of‐flight mass spectrometry

Building‐related health effects are frequently observed. Several factors have been listed as possible causes including temperature, humidity, light conditions, presence of particulate matter, and microorganisms or volatile organic compounds. To be able to link exposure to specific volatile organic compounds to building‐related health effects, powerful and comprehensive analytical methods are required. For this purpose, we developed an active air sampling method that utilizes dual‐bed tubes loaded with TENAX‐TA and Carboxen‐1000 adsorbents to sample two parallel air samples of 4 L each. For the comprehensive volatile organic compounds analysis, an automated thermal desorption comprehensive two‐dimensional gas chromatography high‐resolution time‐of‐flight mass spectrometry method was developed and used. It allowed targeted analysis of approximately 90 known volatile organic compounds with relative standard deviations below 25% for the vast majority of target volatile organic compounds. It also allowed semiquantification (no matching standards) of numerous nontarget air contaminants using the same data set. The nontarget analysis workflow included peak finding, background elimination, feature alignment, detection frequency filtering, and tentative identification. Application of the workflow to air samples from 68 indoor environments at a large hospital complex resulted in a comprehensive volatile organic compound characterization, including 178 single compounds and 13 hydrocarbon groups.     

Evaluation of a new graphitized carbon black employed in sampling volatile organic compounds

A new adsorbent, high-surface-area graphitized carbon black (HSGCB), with a surface area of 560 m²/g, superior to that of commonly traded graphitized carbons, was studied. The evaluation was performed in terms of breakthrough volumes and thermal desorption recoveries of substances representative of the main classes of organic compounds. HSGCB was found to be an interesting alternative to activated charcoal for volatile compounds in that it can be used in thermal desorption.     

Experimental study on solvent-less sample preparation methods: Membrane extraction with a sorbent interface, thermal membrane desorption application and purge-and-trap

Different solvent-free sample preparation techniques for the enrichment of volatile and semivolatile organic compounds from aqueous samples for subsequent gas chromatographic separation and detection are compared. The methods under study are purge-and-trap, membrane extraction with a sorbent interface in two different configurations, and thermal membrane desorption application. The study has been performed with polar as well as with non-polar compounds in respect to sampling yield, enrichment, repeatability and analysis cycle rate. All experiments have been performed with a mobile GC–MS system.     

元素有机化合物在合成应用中的发展

本文回顾了元素有机化合物在有机合成中应用的发展史。分别叙述两位诺贝尔奖金获得者,Brown和Wittig,以及Vollhardt和野依良治成功的经历。对元素有机化学应用于有机合成作了展望。     

Gas chromatography-mass spectrometry as a tool for estimating odour concentrations of biofilter effluents at aerobic composting and rendering plants

The relationship between chemical concentrations (gas chromatography–mass spectrometry analysis) and odour concentrations (olfactometry) was studied for biofilter emissions from four aerobic vegetable, fruit and garden waste (VFG) composting plants and one animal rendering plant. For the VFG composting plants, the study revealed a good linear relationship of the odour concentration with the total volatile organic compounds (VOC) concentration (R²=0.97, n=16) as well as with the concentration of esters and ketones (R²=0.9, n=19). For biofilter emissions of the animal rendering plant, the total VOC concentration was a poor estimator for odour concentration. However, for this type of odour, concentrations of organic sulphur containing compounds correlated well with odour concentrations (R²=0.94, n=8). The results of the study also showed that the relationship between chemical and odour concentrations is specific for each type of odour and cannot be generalized.     

二次有机气溶胶形成的化学过程

挥发性有机化合物的光氧化过程和光氧化产物的气态/粒子态均分过程是二次有机气溶胶形成的重要原因.二次有机气溶胶形成的化学机理主要涉及到挥发性有机化合物的光氧化过程及其一系列的后续反应,它们导致了对流层中臭氧浓度的增加和二次有机气溶胶的形成.本文将重点介绍二次有机气溶胶形成的重要化学过程和量子化学计算研究.     

有机硼化合物的质谱分析

对有机硼化合物进行质谱分析,考察不同种类仪器对样品分析的影响,确定使用电喷雾质谱仪效果最好。进一步考察了流动相、正负离子检测模式、离子化试剂及其浓度等因素的影响。实验发现:样品浓度为1×10-4mol/L,使用V(甲醇):V(H2O)=1:1的混合溶剂为流动相,正离子检测,0.1mol/LNa 为离子化试剂条件下可得到满意的谱图。     

Determination of Organic Compounds,Fulvic Acid,Humic Acid,and Humin in Peat and Sapropel Alkaline Extracts

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.