异菸酸十六烷酯作中性载体的镍离子选择电极

本文报道了一种镍离子选择性电极,它以我们合成的异菸酸十六烷酯作中性载体,该电极对浓度范围为10~(-1)～8×10~(-5)mol/L的镍离子有线性响应,斜率为-25.5±0.4 mV/pC_((Ni)~(2+))(20℃).相对于钠、钾、锂、钙、锡、铁、钴、铜离子的选择性系数分别为:8.1×1~(-5)、8.6×10~(-5)、8.2×10~(-5)、4.1×10~(-3)、7.5×10~(-4)、3.2×10~(-2)、8.0×10~(-2)、4.4×10~(-1).电极重现性优良,响应较快,用交流阻抗法研究了电极膜的传导机理,实验结果表明电极过程受扩散过程控制。     

鲁米诺-AuCl4^- -H2O2体系化学发光反应的研究——-矿石中痕量金的测定

液相化学发光分析法是一种灵敏度很高的分析方法。有人曾用此法以测定痕量金,检测极限1×10~(-8)g/mL金,工作曲线的线性范围1×10~(-8)～1×10~(-7)g/mL金。本文首次提出并用自制液相化学发光分析仪(图1)研究了鲁米诺-AuCl_4~--H_2O_2液相化学发光体系,确定了用这一体系测定金的最佳条件,制定了测定的具体方法。检测极限4×10~(-11)g/mL金,工作曲线的线性范围1×10~(-10)～1×10~(-5)g/mL金,相对标准偏差     

鲁米诺-8-羟基喹啉-5-磺酸-镉(Ⅱ)-过氧化氢化学发光体系研究

报道了Cd(Ⅱ)对鲁米诺-8-羟基喹啉-5-磺酸-过氧化氢体系的化学发光具有增强作用的实验事实,建立了测定Cd(Ⅱ)的分析方法.该法线性范围为2.0×10~(-8)～1.0×10~(-6)g/mL;相对标准偏差为3.5%;检出限为1.0×10~(-8)g/mL.用于合金样品中Cd(Ⅱ)的分析,结果良好.     

无机偶合反应化学发光分析 Ⅱ.H_2O_2-Na_2S_2O_3-鲁米诺体系测定痕量钼

本文将钼催化过氧化氢氧化硫代硫酸钠的反应与鲁米诺-H_2O_2化学发光反应相偶合,建立了痕量钼的无机偶合反应化学发光分析法。此方法的检出限是1.2×10~(-10)g/ml钼,相对标准偏差为2.7％(对5×10~(-9)g/ml钼11次测定),工作曲线的线性范围为1×10~(-9)～1×10~(-3)g/ml。此法巴成功地用于天然水中痕量钼的测定。     

碳毡电极对镧、镝、镱的富集分离

本文提出用碳毡电极富集和分离稀土元素镧、镝、镱(10~(-4)—10~(-9)g/mL)。研究了富集效率、电场影响、洗脱效率、分离效率、饱和富集率和电极重现性。实验结果表明:碳毡电极对浓度为10~(-5)g/mL以下的镧、镝、镱水溶液富集效率为90.5％以上,当电场负于各元素还原电位时富集效率明显上升,反之下降。被富集元素的洗脱效率高于89.3％。对10~(-5)g/mL的上述三种元素混合液进行分离时镧、镝和镱三者的富集效率分别为3.7％、30.4％和56.4％。每克碳毡电极对镧、镝、镱的动态饱和富集车分别为0.953×10~(-3)、1.072×10~(-3)和1.089×10~9-3),静态饱和富集率分别为1.137××10~(-3)1.173×10~(-3)和1.196×10~(-3)。电极经处理后十次重复使用所测富集效率的贝塞耳标准差小于0.95％。     

稀土总量的鲁米诺化学发光法测定

本法研究了离子交换分离-化学发光法测定稀土总量,其检测限为0.25ppb.线性范围为5.5×10~(-5)g/ml—2.2×10~(-10)g/ml,相对标准偏差为3.2％(浓度为1.1×10~(-9)g/ml)。同时,我们还发现Brij-35的加入,可以提高方法的灵敏度。检测限降低了7.6倍。将该法应用于矿样分析,结果令人满意。     

二阶导数极谱法同时测定氯菊酯和生物丙烯菊酯及其电极过程研究

本文对氯菊酯的极谱行为进行了研究,发现在pH1.1乙醇-B.R缓冲溶液中-1.25V处氯菊酯有一还原峰,在-1.04V处生物丙烯菊酯有一还原峰。其线性范围分别为8×10~(-6)～6×10~(-5)g/ml和4×10~(-7)～6×10~(-5)g/ml。氯菊酯的极谱波系吸附控制的还原波,电子转移数为2。应用本法对氯菊酯,生物丙烯菊酯进行同时测定,结果令人满意。回收率为97.2％～105.5％。     

铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究

本文通过对铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究,建立了一个测定铬(Ⅵ)的高灵敏化学发光分析法。方法的检出限为2×10~(-11)g/ml铬(Ⅵ);相对标准偏差小于2％(对1×10~(-10)g/ml铬(Ⅵ)11次测定);校正曲线的线性范围是1×10~(-10)～6×10~6g/ml铬(Ⅵ)。此方法已用于环境水样中铬(Ⅵ)的测定。     

溴金酸-罗丹明B和氯金酸-罗丹明6G超高灵敏显色反应的研究——离心光度法测定金

本文研究了一个超高灵敏的测定金的方法,离心光度法。在Au-Br-RB体系中络合物λ_(max)=559nm,表观摩尔吸光系数ε_(559)=3.39×10~(11)L·mol~(-1)·cm~(-1),Au(Ⅲ)浓度(0.20×10~(-5)～2.5×10~(-5)μg/10 ml呈线性关系;Au-Cl-R6G体系络合物λ_(max)=531 nm,表观摩尔吸光系数ε_(531)=2.52×10~8L·mol~(-1)·cm~(-1),Au(Ⅲ)浓度(0.20×10~(-2)～2.4×10μg/10ml。呈线性(Ⅲ)关系。本法已用于某些低品位矿样中金的分析,分析结果与标准值相吻合。探讨了超高灵敏的显色反应机理。     

超痕量钌的催化光度分析—KIO4—罗丹明B新体系

钌的催化动力学分析法颇多,但检出限低于10~(-9)g/L级的甚少。Alekseeva等基于Ru(Ⅲ)对IO_4~-氧化[Fe(phen)_3]~(2+)反应的催化作用,建立了一个检出限和测定范围分别为5×10~(-9)g/L和10—140×10~(-9)g/L Ru的催化电位法。Rysev等利用Ru(Ⅲ)-IO_4~--金莲橙OO催化褪色体系可测定2×10~(-9)g/L的Ru。     

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.