丙醇-硫酸铵-水液-液体系萃取分离铂、钯、铑和金

研究了丙醇－（NH4）2SO4－水液－液体系对铂（Ⅱ）,钯（Ⅱ）,铑（Ⅲ）和金（Ⅲ）氯化亚锡络阴离子的萃取行为及体系在盐酸介质中的分相条件。实验表明在盐酸介质中体系可同时萃取铂（Ⅱ＿,钯（Ⅱ）,铑（Ⅲ）和金（Ⅲ）,对铂,钯,铑 和金的萃取率分别为99．4％,99．0％,98．3％和99．8％,方法可用于从贱金属中分离铂,钯,铑,金,对阳极泥,砂铂矿,废催化剂样品的分离分析结果与其它方法相符。     

萃取分离-差示导数极谱法测定铂、钯、铑、金中超微量铱

目前,铂族元素的测定以比色法为多,用极谱法测定贵金属的报导不甚多。国内曾报导利用催化极谱测定矿石中微量铱的方法,但铑的允许量只为铱的20倍,大干20倍的铑就必须采用分离手续。由于在常温下,铂、钯、铑、金与快热粉,二氯化锡生成三元络合物,并易被萃入氯仿,而铱则需在加热条件下才能生成三元络合物,因此利用温度的差异可使铱与铂、钯、铑、金进行分离,本文将萃取分离与差示极谱法结合,可在铂、钯、铑、金中进行超微量铱的测定。铱的工作曲线:在25ml分液漏斗中各加入6ml     

用二乙基二硫代磷酸作贵金属的萃取分离

本文研究了用二乙基二硫代磷酸作萃取剂时,一些贵金属的萃取行为。文中着重考查了铂在萃取过程中的行为,并研究了萃取的适宜条件。实验表明,由于光化学反应,铂会部分进入有机相,只要避免光照,铂可定量留于水相,根据研究的结果,提出了一个大量钯、银与少量铂、铑、铱萃取分离的方法,方法简便快速。此法能应用于钯、银合金中铂、铑铱的分析。     

氯化钠存在下丙醇-碘化钾体系萃取分离铂、钯的研究

研究了氯化钠存在下丙醇－碘化钾体系对铂（Ⅱ）、钯（Ⅱ）萃取行为及体系在盐酸介质中的分相条件。在盐酸介质中,体系可同时萃取铂（Ⅱ）、钯（Ⅱ）,萃取率分别为99．8％、99．4％,方法可用于从贱金属中分离铂、铯 。对阳极泥、砂铂矿、废催化剂样品中的铂、钯进行了分离,分析结果与其它方法相符,并对萃取机理也进行了探讨。     

贵金属同时浮选分离富集行为的研究及ICP—AES的测定

本文通过对贵金属－碘化钾－孔雀绿显色体系的浮选行为研究，建立了一种同时浮选选富集分离铂、钯、铑、铱、金的新方法。     

粗银中微量钯铂的分离及测定

二苄基二硫代乙二酰胺(DBDO)法测定钯是一个较好的方法,但不能用于粗银中钯的直接测定而必须进行分离。一般常在盐酸介质中用丁二酮肟萃取分离钯,但对粗银试样,由于氯离子与银生成氯化银沉淀,使操作不能进行。本文改在硝酸介质中用丁二酮肟萃取分离钯,并将丁二酮肟钯直接转化为二苄基二硫代乙酰胺钯,方法十分简便迅速。文献用二乙基二硫代磷酸钠作钯,银与铂、铑、铱的分离,并指出:由于光化学反应,铂会部分进入     

贵金属同时浮选分离富集行为的研究及ICP－AES的测定

本文通过对贵金属－碘化钾－孔雀绿显色体系的浮选行为研究，建立了一种同时浮选富集分离铂、钯、铑、铱、金的新方法。实验结果表明，在０．３６ｍｏｌ／ＬＨＣｌ０．１ｍｏｌ／ＬＫＩ和２．４×１０￣（－４）ｍｏｌ／ＬＭＧ的溶液中，加入环已烷振荡１ｍｉｎ，铂、钯、铑、铱、金可被定量浮选，继而用ＩＣＰ－ＡＥＳ测定。对含量为５～１５０μｇ的贵金属，浮选回收率分别为铂８８．６％～９５．７％，钯９２．３％～９９．５％，铑９３．７％～１０１％，铱９２％～９８．５％，金８６．４％～９４％。方法应用于铜镍矿、铂网废料等物料中上述贵金属元素的测定，结果满意。     

泡沫塑料对贵金属-碘化亚锡-络合物的吸附分离行为研究

本文通过泡沫塑料对贵金属-碘化亚锡络合体系富集分离的条件、性能和机理的研究,建立了一种泡沫塑料同时富集分离微量铂、钯、锗、铱、金的新体系.实验结果表明,在1.0mol/L HCl、0.6mol/L KI和0.01mol/L SnCl_2的溶液中,振荡吸附30min.各元素分配系数均在10~5以上,吸附容量(mmol/g)分别为:铂0.25、钯0.24、铑0.12、铱0.10、金0.52,回收率分别为:铂99.2％、钯98.6％、铑97.8％、铱98.0％、金97.8％.试样中贵金属采用ICP-AES、FAAS测定,该方法用于砂铂矿、废催化剂、铜阳极泥等物料中铂、钯、铑、铱、金的测定,测定结果与其它方法对照相符。本文还进行了吸附动力学研究和富集物的红外光谱分析。     

丙醇-氯化钠-水体系萃取铑(Ⅲ)-氯化亚锡-2-巯基苯并噻唑络合物的研究与应用

研究了丙醇－氯化钠双水相体系萃取铑（Ⅲ）－氯化亚锡－2－巯基苯并噻唑（MBT）络合物的萃取行为及在丙醇萃取相中的光度性质；实验表明，在HCl介质中，铑（Ⅲ）的萃取率是99％，方法可从Fe、Al、Pb、Zn、Ca等常见金属基体中分离铑（Ⅲ），并建立了双水相体系萃取分光光度法测定微量铑（Ⅲ）的新方法。     

铅试金法富集硫化铜镍矿中痕量铑铱的研究

本文采用加铂钯混合物的铅试金法对矿石中铑铱的富集进行了系统的研究。确定了加入6mg铂和4mg钯的铅试金法富集硫化铜镍矿中铑铱最好,铑铱的标准回收均达90％以上。50g矿样中含金量<10mg、含银量<5mg不干扰铱的富集;含金量<100mg、含银量<10mg不干扰铑的富集。较好地解决了矿石中铑铱的富集问题。国内外一些试金分析工作者曾用加金、钯、铂、铂金混合物的铅试金法富集矿石中的铑     

Organogermyl,Organostannyl, and Organoplumbyl Phosphines,Arsines, Stibines,and Bismuthines

The preparation, properties, and reactions of the compounds named in the title are described, with particular reference to the possible participation of (p→d)_π components in the bonding between the group IVB and the group VB elements.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

Structural, magnetic, and spectroscopic studies of YAgSn, TmAgSn, and LuAgSn

The rare earth-silver-stannides YAgSn, TmAgSn, and LuAgSn were synthesized from the elements by arc-melting and subsequent annealing. The three stannides were investigated by X-ray powder and single-crystal diffraction: NdPtSb type, P6₃mc, Z=2, a=468.3(1), pm, wR₂=0.0343, 353 F² values, 12 variables for YAgSn, and ZrNiAl type, P6¯2 m, a=726.4(2), , wR₂=0.0399, 659 F² values, 15 variables for TmAgSn, and a=723.8(2), , wR₂=0.0674, 364 F² values, 15 variables for LuAgSn. Besides conventional laboratory X-ray data with monochromatized Mo radiation, the structures were also refined on the basis of synchrotron data with , in order to clarify the silver-tin ordering more precisely. YAgSn has puckered, two-dimensional [AgSn] networks with Ag-Sn distances of 278 pm, while the [AgSn] networks of TmAgSn and LuAgSn are three-dimensional with Ag-Sn distances of 279 and 284 pm for LuAgSn. Susceptibility measurements indicate Pauli paramagnetism for YAgSn and LuAgSn. TmAgSn is a Curie-Weiss paramagnet with an experimental magnetic moment of 7.2 μ_B/Tm. No magnetic ordering is evident down to 2 K. The local environments of the tin sites in these compounds were characterized by ¹¹⁹Sn Mössbauer spectroscopy and solid-state NMR (in YAgSn and LuAgSn), confirming the tin site multiplicities proposed from the structure solutions and the absence of Sn/Ag site disordering. Mössbauer quadrupolar splittings were found in good agreement with calculated electric field gradients predicted quantum chemically by the WIEN2k code. Furthermore, an excellent correlation was found between experimental ¹¹⁹Sn nuclear magnetic shielding anisotropies (determined via MAS-NMR) and calculated electric field gradients. Electronic structure calculations predict metallic properties with strong Ag-Sn bonds and also significant Ag-Ag bonding in LuAgSn.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

Borinium, borenium, and boronium ions: synthesis, reactivity, and applications

Boron cations are elusive and highly electrophilic species that play a key role in the chemistry of boron. Despite early interest in the chemistry of boron cations, until recently they have largely remained chemical curiosities. However, hints at harnessing their potential as potent electrophiles have begun to appear and developments in weakly coordinating anion technology suggest that this is an area of research that is ripe for exploration. It has been nearly 20 years since the last major review on boron cations; herein we summarize the progress in the area since that time.     

Pi bonding and negative hyperconjugation in mono-, di-, and triaminoborane, -alane, -gallane, and -indane

A systematic quantum chemical investigation of mono-, di-, and triaminoborane, -alane, -gallane, and -indane is carried out to determine quantitatively the effects of pi bonding and negative hyperconjugation on structures, energetics, and rotational barriers in these systems. Pi bonding plays a significant role in the aminoborane compounds, but becomes rapidly less significant in the aminoalanes, -gallanes, and -indanes. For each main-group metal X investigated, X-N rotational barriers are found to be essentially equal depending only on the number of remaining in-plane amino groups. The contribution of negative hyperconjugation to reducing rotational barriers, as assessed from natural bond orbital (NBO) delocalization energies, is independent of the pyramidalization of the out-of-plane amino group, and is also dependent only on the number of rotated groups. Optimized tris[bis(trimethylsilyl)amino]-substituted structures of boron, aluminum, gallium, and indium are found to compare quite well with available experimental structural data, and exhibit X-N torsion angles that are independent of the central metal atom.     

Transition-metal-free O-, S-, and N-arylation of alcohols, thiols, amides, amines, and related heterocycles

A new protocol for the Ullmann-type arylation process of different aromatic heterocycles without any transition-metal catalyst, implying the use of a combination of an excess of potassium hydroxide and dimethyl sulfoxide, is described. The reaction can be performed between a broad range of starting nucleophiles including phenol, alcohols, amines, nitrogen-containing five-membered systems such as pyrazoles, imidazoles, and indoles, and amides with haloarenes, iodide and bromide derivatives giving the best results, the possible pathway involving the in situ generation of the corresponding benzyne intermediate. When the reaction was performed with 2-iodoaniline and either carboxamides or isothiocyanato derivatives, the corresponding benzoazole derivatives were obtained.     

Metal-Directed Formation of Tetra-, Hexa-, Octa-, and Nonanuclear Complexes of Magnesium,Calcium, Manganese,Copper, and Cadmium

Efficacious metal control of self-assembly of dialkylketipinate dianions leads to completely different supramolecular assemblies. The structures of grid 1 , double-decker 2 , triple-decker 3 , and metalla-spherand 4 were characterized by X-ray crystallographic analyses or by NMR spectroscopy.     

铬,硒,镉,锰与心脑血管疾病

通过对５０例心脑血管疾病病人及５０例健康对照组血中微量元素铬、硒、镉、锰的检测分析证实，心脑血管疾病病人血清Ｃｒ、Ｓｅ含量下降，Ｃｄ含量未见明显升高，并进一步探讨了这些微量元素与心脑血管疾病的发生发展的关系及其临床意义。