离子交换分离—氢化物原子吸收光谱法测定紫铜中微是量硒

采用阳离子交换树脂离子分离铜，发生氢化物原子吸收光谱法测定硒，上柱溶液酸度在０－７％，硒的回收率在９６－１０１％，过柱溶液中铜的浓度低于０．０１μｇ／ｍＬ。方法检出限为５×１０＾－５％，分析紫铜中４．４×１０＾－４％的硒，相对标准偏差为３％。     

铜（Ⅱ）锌（Ⅱ）－氟哌酸体系电化学行为及示波极谱法研究

铜（Ⅱ）和锌（Ⅱ）分别在０．１ｍｏｌ／ＬＫＨ＿２ＰＯ＿４－Ｎａ＿２ＨＰＯ＿４缓冲溶液（ｐＨ６．５）和０．２５ｍｏｌ／ＬＮＨ＿４Ｃｌ溶液中，与氟哌酸形成良好的络合吸附波，峰电位分别为－０．２６Ｖ和－１．２８Ｖ（ｖｓ；ＳＣＥ）；络合比分别为１：３和１：２；峰电流与铜（Ⅱ）和锌（Ⅱ）的浓度均在４．０×１０￣（－７）～５．０×１０￣（－６）ｍｏｌ／Ｌ范围内呈线性关系，检测限分别为７．０×１０￣（－８）和５．０×１０￣（－８）ｍｏｌ／Ｌ。用线性扫描和循环伏安法等手段研究体系的行为，表明均具吸附性，而铜（Ⅱ）－氟哌酸体系属络合物中铜（Ⅱ）的两电子还原的可逆过程。     

高锰酸钾－抗坏血酸化学发光体系测定抗坏血酸

本文研究了高锰酸钾－抗坏血酸化学发光体系，建立了测定抗坏血酸的化学发光分析新方法。线性响应的浓度范围为５．０×１０￣（－７）ｍｏｌ／Ｌ～４．０×１０￣（－５）ｍｏｌ／Ｌ检出限为３．０×１０￣（－７）ｍｏｌ／Ｌ对２．５×１０￣（－６）ｍｏｌ／Ｌ抗坏血酸进行１０次平行测定，相对标准偏差为１．６％。考察了２２种物质的干扰情况。用于维生素Ｃ片剂及注射液中抗坏血酸含量测定，结果令人满意。     

5，10，15，20－四（3－溴－4－磺酸苯基）卟啉光度法测定痕量铜的研究

本文研究了新水溶性卟啉试剂５，１０，１５，２０－四（３－溴－４－磺酸苯基）卟啉［Ｔ（３－ＢｒＰ）ＰＳ＿４与铜的显色反应。在ｐＨ３，铜与５，１０，１５，２０－四（３－溴－４－磺酸苯基）卟啉形成１：１的稳定配合物。此配合物的最大吸收波长位于４１２．８ｎｍ，摩尔吸光系数为２．６１×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。铜量在０～３．０μｇ／２５ｍＬ范围内符合比尔定律，工作曲线回归方程为ｙ＝０．００９４３、＋０．１６７ｘ，相关系数为ｒ＝０．９９９７。方法有较高的灵敏度和较好的选择性，直接用于大米和茶叶中痕量铜的测定，结果与ＡＡＳ法一致。     

铜（Ⅱ）锌（Ⅱ）—氟哌酸体系电化学行为及示波极谱法研究

铜（Ⅱ）和锌（Ⅱ）分别在０．１ｍｏｌ／ＬＫＨ２ＰＯ４－Ｎａ２ＨＰＯ４缓冲溶液（ｐＨ６．５）和０．２５ｍｏｌ／ＬＮＨ４Ｃｌ溶液中，与氟哌酸形成良好的络合吸附波，峰电位分别为－０．２６Ｖ和－１．２８Ｖ（ｖｓ．ＳＣＥ），络合比分别为１：３和１：２，峰电流与铜（Ⅱ）和锌（Ⅱ）的浓度均在４．０×１０＾－７～５．０×１０＾－６ｎｏｌ／Ｌ范围内呈线性关系，检测限分别为７．０×１０＾－８和５．０×１０＾－８ｍｏｌ     

钒－槲皮素－氯酸盐体系极谱催化波的研究

在醋酸盐缓冲底液中，钒能与槲皮素形成络合物，并吸附在汞电极上，在氯酸盐存在下，在Ⅴ（Ⅳ）还原至Ⅴ（Ⅲ）过程中，形成催化波。用单扫二阶导数极谱法测定时，钒浓度在１．０×１０￣（－９）～５．０×１０￣（－６）ｍｏｌ／Ｌ与峰高有正比关系，检出下限为５．０×１０￣（－１０）ｍｏ１／ｍＬ。测得电活性络合物的组成为Ⅴ（Ⅳ：Ｑｕ＝１：２。平行催化反应的速率常数Ｋ＝１．５×１０￣（４）（ｍｏｌ／Ｌ）￣（－１）ｓ（－１）。     

银（Ⅰ）－硫脲－四正丁基溴化铵体系电致化学发光法测定水中痕量银

本文研究了银（Ⅰ）－硫脲－四正丁基溴化铵体系的电致化学发光（ＥＣＬ）。发现在正矩形脉冲下，银对含有硫脲的ＴＢＡＢｒ溶液的ＥＣＬ有明显催化作用，银（Ⅰ）的浓度在１．４×１０￣（－８）～３．５×１０￣（－６）ｍｏｌ／Ｌ范围内与ＥＣＬ强度呈良好线性关系。检出限为９．０×１０￣（－９）ｍｏｌ／Ｌ相对标准偏差为５％。用于天然水中银的测定，获得较满意的结果。     

极谱法快速同时测定锌电解液中微量铜、镉、钴

铜、镉、钻在了丁二酮肟－氯化铵－柠檬酸钠－ＨＡｃ－ＮａＡｃ体系中有灵敏的极谱波。其峰电位分别为－０．２４Ｖ、－ ０．７９Ｖ和－０．９３Ｖ,线性范围分别为４ × １０~（－６）～ ４ × １０~（－３）、５ × １０~（－６）～ ５×１０~（－３）、１×１０~（－７）～１×１０~（－４）ｇ／Ｌ,检测限分别为２×１０~（－６）、４ × １０~（－６）和５×１０~（－８）ｇ／Ｌ。方法无需预处理直接用于锌电解液中微量铜、镉、钴的测定,结果令人满意。     

吸附络合物体系的示波分析

Ｉｎ（Ⅲ）在ｐＨ４５７ＨＡｃＮａＡｃ０．１％ＶＣ０．０６％ＨＣｕＰ溶液中，用示波计时电位法可获得良好示波图，其切口电位为Ｅ＝０９０（Ｖｓ．ＳＣＥ），切口高度与Ｉｎ（Ⅲ）浓度在８００×１０－７～１４×１０－５ｍｏｌ／Ｌ范围内成正比，检出限可达５０×１０－７ｍｏｌ／Ｌ吸附络合物组成为Ｉｎ（Ⅲ）：铜铁试剂（ＨＣｕｐ）＝１∶１，条件稳定常数为５９×１０３     

新显色剂N－辛基－N＇－（氨基对苯磺酸钠）硫脲（OPT）与铜（Ⅱ）显色反应的研究和应用

Ｎ－辛基－Ｎ＇－（氨基对苯磺酸钠）硫脲是新合成的一种显色剂，该试剂极易溶于水而形成无色溶液。在ｐＨ３．６～５．２的ＨＡｃ－ＮａＡｃ缓冲体系中，试剂与铜（Ⅱ）形成一种稳定的蓝色水溶性配合物，其组成比为：Ｃｕ（Ⅱ）：ＯＰＴ＝１：３。配合物的最大吸收波长位于３０１．４ｎｍ，表观摩尔吸光系数ε＿（３０１．４）＝１．８２×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。Ｃｕ（Ⅱ）在０～１０μｇ／２５ｍＬ服从比尔定律，相关系数ｒ＝０．９９９６，方法的检出限为３．８５×１０￣（－９）ｇ／ｍＬ。本法灵敏度高，选择性好、操作简单，可直接在水相中测定。将本法用于合金钢和生物制品中微量铜的测定，均获得满意结果。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.