镧系金属有机化合物中金属的测定

欲测定镧系金属有机化合物中金属的含量,首先要破坏样品中的有机组份,使金属成为离子,然后再分析金属含量。破坏金属有机化合物常用的方法有干法与湿法两种。干法就是用加热来破坏样品;湿法就是用硝酸加热破坏(也叫消化)。我们用湿法破坏对空气敏感的镧系金属有机化合物中的有机组份,以EDTA络合滴定法测定了金属含量,并比较了不同配位体的镧系金属有机化合物对金属分析结果的影响。     

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。     

超临界流体色谱在金属络合物和金属有机化合物中的分析应用

超临界流体色谱（SFC）在色谱分离过程中能在较低的温度下分析对热不稳定性的化合物,包括金属络合物和金属有机化合物。本文总结了近来文献报道的各种过渡金属、重金属、镧系和锕系以及铅、汞和锡的金属有机化合物的SFC分离,还讨论了SFC检测系统和金属有机化合物的溶解度的测定。     

超铀金属有机化学研究进展

锕系金属有机化合物因其独特的电子结构和成键性质而备受关注.锕系元素的高毒性和放射性以及对水和氧的超敏感性造成锕系金属有机化合物的合成条件及表征手段都比较苛刻.而超铀元素的获取途径更为严苛,加之极其强的放射性,超铀金属有机化合物的研究报道甚少.近年来,随着合成技术及表征技术的快速发展,一些结构新颖的超铀金属有机化合物被合成,通过对其电子结构、成键模式及理化性质的研究进一步加深了对超铀元素的认识和理解.综述了近年来超铀金属有机化合物的合成及其成键性质的研究,以期为系统地理解超铀元素的电子结构和成键规律以及合成结构新颖的超铀金属有机化合物提供指导.     

中国化学会第五届金属有机化学学术讨论会征文通知

中国化学会第五届金属有机化学学术讨论会拟于1988年9月下旬在兰州召开,现开始征集论文。 (一)征文范围 1.金属有机化合物的合成、结构及反应; 2.金属有机化合物的催化反应及动力学研究; 3.金属有机化合物在有机合成中的应用; 4.金属有机化合物在农业,工业,医疗,     

有机金属

有机化合物同金属显然是两类绝不相同的固体,具有完全不同的电子状态。但是天然界就存在具有金属导电性能的典型有机高分子化合物,即石墨。从这事实来看,把有机化合物同金属联在一起来提,也许就不太感陌生了。合成导电性有机化合物的尝试,引起了许多科学工作者的兴趣,已经有二三十年的历史。1967年赖恩斯(Lyons)曾预言:“合成具有电导率在10~4欧~(-1)厘米~(-1)以上的有机材料的日子很可能会到来。从电性质来说,在高压下有机金属已经存在,在常压下目前也已经不远了。”当时是指酞菁铜在高压下具有金属电导,但压力除去立刻失去。时隔不久,到七十年代初就做到了具有金属电导特性的有机化合物,这可说是一个很重要的科学成就。本文将对有机金属作一概括性的介绍。     

铁-锡多核金属有机化合物的合成及表征

铁-锡多核金属有机化合物;二茂铁羧酸;铁-锡多核金属有机化合物的合成及表征     

锕系多重键金属有机化合物研究进展

多重键金属有机化合物在多种催化反应中已经得到广泛的应用, 并取得了很好的研究成果. 目前, 多重键金属有机化合物的研究已成为催化化学领域中一个引人注目的研究热点. 综述了锕系多重键金属有机化合物的研究进展. 根据化合物多重键的不同, 分别讨论了它们的合成及反应性能, 并定性讨论了多重键的性质.     

金属苯炔的合成与化学性质

金属苯炔是一类新颖的杂环芳香化合物.它们可看成是苯炔分子中的一个碳原子被等瓣的过渡金属基团取代而衍生出来的六元杂环化合物.近年来,金属苯炔的化学引起了人们的兴趣和关注.一系列含锇和铼的金属苯炔已被成功地合成和鉴定.这些金属苯炔不仅具有有机化合物的芳香性,还具有金属有机化合物的属性.它们既可以发生芳香体系的经典反应(如亲电取代反应),也可以发生金属有机化合物的反应(如卡宾化合物的形成).     

漫谈金属有机化学

引言金属有机化学和配位化学分别是从有机化学和无机化学两个领域中发展起来而又密切联系的学科,目前已汇成一股洪流,成为近代化学前沿领域之一.它的发展打破了传统的有机化学和无机化学的界限,金属有机化学已成为有机化学中主流之一,它的发展又与理论化学、合成化学、催化、结构化学、生物无机化学、高分子科学等交织在一起. 什么是金属有机化合物?凡是化合物中含有碳-金属键的都是金属有机化合物.不言而喻,根据我国化学名词命名法,凡有金字偏旁的元素与碳成键的化合物,当然属于金属有     

超临界CO2流体萃取重金属的研究进展

超临界CO₂ 流体与金属配合技术相结合开辟了重金属萃取的新途径。本文介绍了超临界CO₂流体萃取重金属的研究现状, 总结了影响萃取的因素, 并对未来的发展趋势作了展望。     

准东煤中碱金属的赋存形式及其在燃烧过程中的迁移规律实验研究

对新疆煤采用三步化学提取实验(蒸馏水洗、醋酸铵洗、稀盐酸洗)以分析其碱金属赋存特性,对水溶的阴离子进行了离子色谱分析。分别检测了在不同温度、不同停留时间下准东煤灰的碱金属量,并用Factsage软件模拟该煤灰中碱金属的析出形式。结果表明,煤中的钠主要是水溶钠,钾主要以不可溶钾存在,水溶碱金属主要以水合离子形式的氯化物存在。准东煤中碱金属在400~600℃析出最快,主要是水溶态碱金属的释放,碱金属的释放主要发生在燃烧后期。灰中碱金属在高温下会与烟气中的成分发生反应,主要产物是氯化物以及氢氧化物。在700℃钠对准东煤中低温共融物的形成有很大贡献。     

Simultaneous determination of traces of heavy metals by solid-phase spectrophotometry

A coupling sensitive solid phase spectrophotometric (SPS) procedure for determination of traces of heavy metals (Me-SPS) and multicomponent analysis by multiple linear regressions (MA), a simple methodology for simultaneous determination of metals in mixtures was inaugurated. The Me-SPS procedure is based on sorption of heavy metals on PAN-resin and direct absorbance measurements of colour product Me-PAN sorbed on a solid carrier in a 1-mm cell. This methodology (Me-SPS-MA) was checked by simultaneous determination of metals in synthetic mixtures with different compositions and contents of metals important in pharmaceutical practice: Zn, Pb, Cd, Cu, Co, and Ni. Good agreement between experimental and theoretical amounts of heavy metals is obtained from the recovery test (78.3–110.0%). The proposed method enables determination of particular metal ion at the ng mL⁻¹ level and it was successfully applied to the determination impurities from heavy metal traces in pharmaceutical substances (Cu in ascorbic acid, Pb in glucose, and Zn in insulin). The proposed procedure could be possible contribution to the development of pharmacopoeial methodology for a heavy metals test.     

Methode d'elution selective pour l'extraction des metaux lourds de l'eau de mer sur resine chelatante: A selective method of elution for the extraction of heavy metals from sea waters on a chelating resin

A selective method of elution for the extraction of heavy metals from sea waters on a chelating resin.The extraction of heavy metals in sea water with Chelex 100 prior to their determination by atomic absorption spectrometry (a.a.s.) with electrothermal atomization is discussed. Maximum retention of heavy metals is not obtained with the resin in the H⁺ form, because it is gradually transformed in contact with sea water by the fixation of alkali and alkaline-earth cations which are eluted simultaneously with the heavy metals and interfere during a.a.s. The separation of heavy metals is quantitative on Chelex 100 in the Ca²⁺ form; treatment with dilute acetic acid (1 + 99) eliminates the alkali and alkaline-earth metals fixed on the resin before elution or the heavy metals. Elution with 1 M nitric acid gives simultaneous and quantitative recovery of Cu, Pb, Ni, Zn, Cd and Co; intermediate elution with 0.01 M nitric acid isolates Zn, Cd and Co from Cu and Pb, which are subsequently eluted with 1 M nitric acid.     

光谱技术在纺织品检测中的应用（一）--X荧光能谱仪在纺织品重金属检测中的应用

近年来,世界各国对纺织品中的有害物质含量的控制已越来越严格。本文对纺织品中重金属检测方法的现状进行了概括,进一步介绍了X荧光能谱法在纺织品重金属检测上的应用。采用X荧光能谱法检测布样中的重金属和采用电感耦合等离子体原子发射光谱法（ICP-AES）检测结果基本一致。结果表明：X荧光能谱法是一种有效的纺织品中重金属检测方法,也为纺织品中重金属的检测提供了一种快速、简便、无损的初筛方法。     

Analysis of trace metals in water by in-situ sample pre-concentration combined with wavelength dispersive X-ray fluorescence spectroscopy and inductively coupled plasma-optical emission spectroscopy

In this paper an earlier work on the use of poly(acrylamidoxime) cloth for use as a passive monitor for trace metals in water by characterizing the sorption of several metals onto the cloth using a continuous flow chamber is extended. The monitors consists of amidoxime chelating groups covalently bound to the surface of a textile encased in a common 35 mm slide holder. Placement of this device in the water to be sampled resulted in the uptake of heavy metals by the chelating groups. After removal of the monitor from water, the metals were analyzed using wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) as well as by acid extraction followed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Correlation between the two methods of analysis varied with maximum correlation of 0.99897 observed for Pb and a minimum correlation of 0.16512 for Mg. The order of the distribution coefficients for the seven metals tested was: Pb> or =Cu>Zn>Cd>Mn>Fe>Mg, in agreement with the order of the stability constants for the amidoxime/hydroxamic acid group for the chelation of the same metals at a pH of 5, with the exception of Fe. Field testing of the monitors was also carried out and a comparison made between active sampling of river water and sampling with the monitors. Results indicated that semiquantitative analysis of trace metals in water may be performed using the passive monitors.     

Removal,recovery and enrichment of metals from aqueous solutions using carbon nanotubes

Environmental pollution caused by toxic metals (heavy metals, radioactive metals, etc.) is one of the major global issues, thus removal of toxic metals from contaminated water seems to be particularly important. On the other hand, the recovery and enrichment of metals, especially noble metals, from waste water is also crucial. To address these issues, nanotechnology plays an essential role in environmental monitoring and pollution control. To remove metals from contaminated water, or enrich metals from waste water, carbon nanotubes (CNTs) and their composites have attracted great attention due to their excellent adsorption performance. The removal efficiency for metal ions by CNTs was observed aroud 10–80 %, which could be improved to approach 100 % by selectively functionalizing CNTs with organic ligands. Herein, we review the applications of CNTs in treatment of toxic metal-containing wastewater for environmental monitoring and metals recovery. Due to their higher sensitivity and selectivity towards the enrichment of metals or detection of toxic metal pollution of the environment, and the latest research progress of using CNT composites for metal treatment is also discussed.     

Determination of trace metal complexes by natural organic and inorganic ligands in coastal seawater.

It is well-documented that organic compounds form strong complexes with most metals in aquatic systems, and that seawater is a complex medium which contains a large variety of organic and inorganic ligands, including colloidal matter. We suggest that most trace metals are complexed in seawater and that some inorganic metals complexes are either labile or not stable. In contrast, metal-organic complexes are often stable and need various and specific treatments to be dissociated. In this paper we try to illustrate a good tendency of some trace metals to be complexed by organic ligands in seawater. A solid-phase extraction method was applied using a C18 column as a resin that is able to separate metals complexed by neutral organic ligands, and the chelamine resin to separate metal species that are present as labile inorganic complexes. The determination of total dissolved metal concentrations was achieved by formatting a metal-8-hydroxyquinoline complex, followed by adsorption on C18 columns and ICP-AES analysis.     

Improved recovery of trace amounts of gold (III), palladium (II) and platinum (IV) from large amounts of associated base metals using anion-exchange resins

The adsorption and desorption behaviors of gold (III), palladium (II) and platinum (IV) were surveyed in column chromatographic systems consisting of one of the conventional anion-exchange resins of large ion-exchange capacity and dilute thiourea solutions. The noble metals were strongly adsorbed on the anion-exchange resins from dilute hydrochloric acid, while most base metals did not show any marked adsorbability. These facts made it possible to separate the noble metals from a large quantity of base metals such as Ag (I), Al (III), Co (II), Cu (II), ¶Fe (III), Mn (II), Ni (II), Pb (II), and Zn (II). Although it used to be very difficult to desorb the noble metals from the resins used, the difficulty was easily overcome by use of dilute thiourea solutions as an eluant. In the present study, as little as 1.00 μg of the respective noble metals was quantitatively separated and recovered from as much as ca. 10 mg of a number of metals on a small column by elution with a small amount of dilute thiourea solution. The present systems should be applicable to the separation, concentration and recovery of traces of the noble metals from a number of base metals coexisting in a more extended range of amounts and ratios.     

Improved recovery of trace amounts of gold (III), palladium (II) and platinum (IV) from large amounts of associated base metals using anion-exchange resins

The adsorption and desorption behaviors of gold (III), palladium (II) and platinum (IV) were surveyed in column chromatographic systems consisting of one of the conventional anion-exchange resins of large ion-exchange capacity and dilute thiourea solutions. The noble metals were strongly adsorbed on the anion-exchange resins from dilute hydrochloric acid, while most base metals did not show any marked adsorbability. These facts made it possible to separate the noble metals from a large quantity of base metals such as Ag (I), Al (III), Co (II), Cu (II), Fe (III), Mn (II), Ni (II), Pb (II), and Zn (II). Although it used to be very difficult to desorb the noble metals from the resins used, the difficulty was easily overcome by use of dilute thiourea solutions as an eluant. In the present study, as little as 1.00 microg of the respective noble metals was quantitatively separated and recovered from as much as ca. 10 mg of a number of metals on a small column by elution with a small amount of dilute thiourea solution. The present systems should be applicable to the separation, concentration and recovery of traces of the noble metals from a number of base metals coexisting in a more extended range of amounts and ratios.