具有生物活性的有机锗化合的研究新进展

综述了近年来发展的具有各种生物活性的六类有机锗化合物的合成及生物活性，即倍半锗和介吗川类有机化合的，锗氧杂，锗氮杂及锗硫杂环酮类化合物，呋喃，噻唑，咪唑、嘧啶取代锗烷及其类似物，烷锗醇，熔锗醚和烷锗酮类化合物，卟啉锗类经合物，其它具有生物活性的有机锗化合物这六类有机锗化合物，并对该领域的研究前景作了展望。     

化学简讯

有关无机化学消息七则氟铂(V)酸二氧 O_2~ [PtF_6]~-:借混合等克分子量的氧和六氟化铂在室温形成。它的化学性质和磁化率与上列结构相符。较高级的氢化锗(锗烷):将锗甲烷在产生臭氧的仪器(静放电)中循环,可获得较高级的锗烷。经气体层析可得20%锗乙烷,26%锗丙烷,10%锗丁烷,0.8%锗戊烷,9.6%锗己烷,0.6%锗庚烷,0.05%锗辛烷和少于0.01%的锗壬烷。氮化铀的熔点:在至少2.9大气压的氮气下,氮     

具有生物活性的有机锗化合物的研究新进展

综述了近年来发现的具有各种生物活性的六类有机锗化合物的合成及生物活性，即倍半锗和介吗川类有机化合物，锗氧杂、锗氮杂及锗硫杂环酮类化合物，呋喃、噻唑、咪唑、嘧啶取代锗烷及其类似物，烷锗醇、烷锗醚和烷锗酮类化合物，卟啉锗类化合物，其它具有生物活性的有机锗化合物这六类有机锗化合物，并对该领域的研究前景作了展望。     

锗的应用与市场分析

分析了锗产量增长速度不快的原因和当前应用领域现状。并根据锗的性质，对锗市场作了分析，提出了扩大锗应用的看法。     

石墨炉原子化器中原子化过程的研究——Ⅳ.石墨管衬底材料对锗原子化的影响

本文研究了标准石墨管、涂钨和涂锆石墨管中锗原子吸光度,吸收信号形状和原子消失速度的变化。实验表明,在涂钨和涂锆石墨管中锗的分析灵敏度有较大的提高。同时实验测得在涂钨石墨管中锗的出现温度为1770K。按公式ΔH°=γTapp求得锗的ΔH°=106.2kcal/mol。它与锗的升华热89.5kcal/mol相近。因此,在涂钨石墨管中锗原子的形成是GeO₂被碳化钨还原成金属锗,随后锗的升华。     

锗的分析概况

本文是关于锗分析方法的综述，共分锗的分析和分离方法，锗的定量法和有机锗Ｇｅ－１３２产量质量控制法研究现状三大部分。锗的分析和分离方法中，介绍了锗的分析方法及分类，锗样品前处理、分离与预浓集的原理和方法，并便 出了有参考价值的图表，锗的定量法中介绍了重量法、容量法、分光光度法、荧光法和发光分析法原子吸收分光光度法、原子发射光法、电化学分析法。每一分析法中又介绍了测定法研究及应用实例。在测定法研究及应     

荧光分光光度法测定蔬菜中的微量锗

1 引 言 有机锗的防病、保健作用已有大量报道,锗与人类的关系越来越受到人们的关注,有关锗的测定方法报道多采用分光光度法和原子吸收光谱法,操作较复杂。荧光分光光度法测定微量锗国内外报道较少。本文采用桑色素测定微量锗,研究了桑色素荧光分光光度法测定锗的前处理条件,建立了蔬菜中微量锗高温灰化、溶样后不经萃取和反萃取的快速测定方法,灵敏度高、方法简单、准确度好,本法适用于植物样品中微量锗的测定。     

1-锗蒽、2-锗蒽及9-锗菲二聚反应的理论研究

采用密度泛函B3LYP/6-311G**方法研究了1-锗蒽的[2+2]、[4+2]及[4+4]二聚反应、2-锗蒽及9-锗菲的[2+2]二聚反应的微观机理和势能剖面,考察了苯溶剂对反应势能剖面的影响,并与锗苯、1-锗萘及2-锗萘的类似反应进行了比较。计算结果表明,[2+2]和[4+4]反应为同步的协同过程,而[4+2]反应为非同步的协同过程。无论从热力学还是从动力学来看,1-锗蒽的[4+2]反应最有利,而[4+4]反应最不利。两种不同的进攻方式(endo进攻与exo进攻)在热力学和动力学上的差别不大。苯溶剂对所研究反应的势能剖面影响较小。1-锗蒽(2-锗蒽)的反应性高于锗苯和1-锗萘(2-锗萘)。     

全氟化和部分氟化锗纳米条带电学和磁学性质的理论研究

通过第一性原理计算分别研究了锯齿型和扶手椅型全氟化和部分氟化锗纳米条带的几何结构、稳定性、电学和磁学性质.结果表明,两类全氟化锗纳米条带的最优构型均为椅式构型,并均表现为非磁的半导体性质.全氟化能够有效地增大锗纳米条带体系的带隙,其带隙随着条带宽度的增加而减小.部分氟化的锯齿型锗纳米条带展现出反铁磁半导体的性质,而相应的扶手椅型锗纳米条带则为非磁性的半导体;这些体系的带隙随着氟化程度的增加而增大,其中部分氟化扶手椅型锗纳米条带的带隙展现出三族行为.所有部分氟化的锗纳米条带均与未氟化部分对应的等宽度锗纳米条带表现出几乎相同的电学和磁学行为,表明氟化能够有效调控锗纳米条带的电学和磁学性质.另外,所有氟化的锗纳米带都具有较高的结构稳定性.     

铜促进的锗亲电试剂与烷基溴合成四烷基锗※

有机锗化合物由于其区别于硅与锡的独特性质而逐渐受到关注. 其中, 以烷基三甲基锗为代表的具有光催化自由基反应活性的烷基锗化合物仍缺乏高效、简便的合成方法. 本工作使用商业可得的三甲基溴化锗和烷基溴化物为原料, 廉价的硫酸铜为催化剂, 在镁粉的存在下以较好的产率获得了一系列烷基三甲基锗化合物. 机理研究表明反应很可能经历原位格氏试剂历程, 添加的铜盐可以加速锗卤化合物与格氏试剂的反应, 从而抑制锗卤化合物被镁粉还原产生二锗物种的副反应. 相比于传统预先制备的格氏试剂, 本工作发展的新方法对酯基或酰胺等官能团有较好的兼容性. 该反应还可以拓展到二甲基二氯化锗和其他烷基溴化物一步合成多种四烷基锗以及锗杂环烷烃类化合物.     

电感耦合等离子体发射光谱法测定锗精矿中锗量

建立了用硝酸、氢氟酸、磷酸溶解样品,电感耦合等离子体发射光谱法测定锗精矿中锗量的方法。试验选择209.426nm作为最优分析谱线,锗的检出限为0.006μg/mL,测定下限为0.020 μg/mL,在磷酸基体匹配的条件下测定,测定范围为1%-15%,与经典碘酸钾滴定法对比,数据一致,相对标准偏差<3%(n=11),加标回收率98%~101%,能够满足快速测定及批量处理锗精矿中1%-15%的锗含量的需求。     

Determination of Germanium in Zinc by Differential Cathode Ray Polarography

Abstract

A differential cathode ray polarographic method is described for determining traces of germanium in zinc and its compounds. The germanium was previously extracted with carbon tetrachloride from the sample solution in hydrochloric acid. After reextraction with water the germanium content was determined polarographically in 1.4 M perchloric acid ? 5.10^?2 M pyrogallol. The detection limit was 0.0012 μg/ml, allowing to detect about 4 ppb of germanium in zinc using 5 g samples.     

Copolymerization of vinyl acetate and unsaturated acids in the presence of germanium tetrachloride in methanol

The influence of catalytic amounts of germanium tetrachloride on the copolymerization of vinyl acetate with acrylic acid and methacrylic acid in methanol is examined. It is shown that germanium tetrachloride exerts different effects on the formation rate, molecular-mass characteristics, and composition of copolymers formed in these systems. For example, at a germanium tetrachloride-to-acrylic acid ratio of 0.02 (mol/mol), an alternating copolymer is formed, whereas in the case of methacrylic acid, a copolymer considerably enriched with methacrylic acid units is produced at the same ratio. The results are explained by different copolymerization mechanisms for both systems.     

酸对微波消解-氢化物发生原子荧光光谱法测定食品中锗的影响

以微波消解为前处理手段,采用氢化物发生原子荧光谱法测定食品中的锗,研究了作为载液的磷酸体积分数和消解过程中残留硝酸对测定结果的影响.磷酸体积分数从5％增加至30％时,标准曲线斜率缓慢上升.认为10％～20％体积分数磷酸适宜作为原子荧光光谱法测锗的载液.硝酸在样品中体积分数超过1％后,锗的荧光信号严重减弱.优化条件后对市...     

蒸馏分离–电感耦合等离子体质谱法测定铜铅锌矿石中微量锗

建立蒸馏分离-电感耦合等离子体质谱法测定铜铅锌矿石中微量锗的方法。采用硝酸-磷酸混合酸消解铜铅锌矿石样品,在盐酸介质中蒸馏分离微量锗,在氦气碰撞池模式下,以103Rh为在线内标进行质谱法测定。锗的质量浓度在0~50 μg/L 范围内线性良好,相关系数为0.9995,方法检出限为0.019 μg/g。用所建方法对3个铜铅锌矿石成分国家一级标准物质进行测定,测定结果的相对标准偏差为4.58%~5.55%(n=7),样品加标回收率为93.0%~102.0%。该方法操作简便,灵敏度高,适用铜铅锌矿石中微量锗含量的测定。     

Patterning NHS-terminated SAMs on germanium

Here we report a simple, robust approach to patterning functional SAMs on germanium. The protocol relies on catalytic soft-lithographic pattern transfer from an elastomeric stamp bearing pendant immobilized sulfonic acid moieties to an NHS-functionalized bilayer molecular system comprising a primary ordered alkyl monolayer and a reactive ester secondary overlayer. The catalytic polyurethane-acrylate stamp was used to form micrometer-scale features of chemically distinct SAMs on germanium. The methodology represents the first example of patterned SAMs on germanium, a semiconductor material.     

Stabilization of germanium(ii) by complex formation in iodimetric titration of germanium

Four factors are important in the reduction of germaniuin(IV) by hypophosphite, namely, proper acidity, temperature, proper concentration of complexing ligand, and time of heating. The complexing ligand is needed to stabilize the germaium(II) ions. Halides, with the exception of fluoride, and phosphate are good complexing ligands for germanium. Tin is quantitatively reduced and titrated under the same conditions. Many foreign ions do not interfere, so that prior separation of germanium can often be avoided. Successful results are presented for titrating germanium in the presence of many metals and for direct determination of germanium in actual samples. Germanium after reduction may be titrated with an iodate solution potentiometrically. The formal oxidation potentials of some germanium half-reactions were estimated and used to interpret the stabilization of germanium(II) by complex formation. Phosphoric acid is recommended as the reduction medium.     

含氟固体锗富集物的处理

含氟的锗富集物的利用,由于氟对玻璃,搪瓷设备的腐蚀以及影响锗的分离,受到了很大限制,作者根据物料中氟存在的不同状态,摸索出用专用试剂,使物料中氟“激活”得易用硼酸将其除去,然后再使“钝”化的锗“活化”,以提高四氮化锗的回收率。用这种综合处理法,可使难处理的含氟固体锗富集物,氯化蒸馏ＧｅＣｌ４的回收率达９１％以上,并彻底消除了对搪瓷反应釜的腐蚀。     

Spectrophotometric determination of germanium in ores, concentrates, zinc-processing products and related materials with phenylfluorone and cetyltrimethylammonium bromide after separation by iron collection and heptane extraction of germanium tetrachloride

A method for determining approximately 0.2 microg/g or more of germanium in ores, concentrates, zinc-processing products and related materials is described. The sample is decomposed by fusion with sodium peroxide and the cooled melt is dissolved in dilute sulphuric acid. Silica, if > 50 mg, is removed by volatilization with hydrofluoric acid. Germanium is separated from sodium salts by co-precipitation with hydrous ferric oxide, the precipitate is dissolved in 3M hydrochloric acid and germanium is subsequently separated from iron(III) and other co-precipitated elements by a single heptane extraction of germanium tetrachloride from approximately 9.4M hydrochloric acid. The extract is washed with 12M hydrochloric acid to remove residual iron(III), then germanium is stripped with water and determined spectrophotometrically with phenylfluorone in a 1.4M hydrochloric acid-0.002M cetyltrimethylammonium bromide medium in the presence of ascorbic acid as a reductant for co-extracted chlorine. The apparent molar absorptivity of the complex is 1.71 x 10(4) l.mole(-1).mm(-1) at 507 nm, the wavelength of maximum absorption. Up to 5 mg of tin(IV), 10 mg of antimony(V) and tungsten(VI) and approximately 50 mg of silica do not interfere. Germanium values are given for some Canadian certified reference ores, concentrates and iron-formation samples and for a metallurgical dust.     

Interference-free atomic spectrometric method for the determination of trace amounts of germanium by utilizing the vaporization of germanium tetrachloride

Trace amounts of germanium can be determined by atomic spectrometry by utilizing the vaporization of germanium tetrachloride at ambient temperature. Using an intermittent or continuous flow reactor, the sample solution was mixed with concentrated hydrochloric acid to form volatile germanium tetrachloride which can subsequently be determined by atomic spectrometry. The conditions for the volatilization of germanium chloride were investigated in detail and rapid method for the determination of trace amounts of germanium in real samples was proposed. A detection limit of 0.5 ng ml⁻¹ (3σ_n−1) was obtained by using atomic fluorescence spectrometric detection and the precision found was 0.8% for a germanium concentration of l00 ng ml⁻¹. Atomic emission and absorption spectrometric methods were also tested. Owing to the high selectivity of the reaction, no interference was found in the determination. The method was applied to the determination of germanium in several standard and certified reference materials; the results obtained were in good agreement with the certified values.