钪-钇-茜素红S异多核络合物极谱吸附波的研究

报道了钪－钇－茜素红Ｓ异多核铬合物的形成及该异多核络合物极谱吸附波测定钪的最佳实验条件。用此方法测定了纯氧化钇中的微量钪,并探讨了该极谱波的性质和电极反应机制。在单扫描示波极谱上用单纯形法和改良的平衡移动法测得该异多核络合物组成的摩尔比为：ｘＳｅ＾３＋：ｘＹ＾３＋：ｘＡＲＡ＝１：２：５。     

钪-钙-茜素S异多核络合物的极谱吸附波

报道了钪－钙－茜素Ｓ（ＡＲＳ）异多核络合物极谱吸附波的形成及利用它测定钪的最佳实验条件。用此方法测定了矿石中的微量钪,并初步探讨了该极地的性质和电极反应机理。在单扫描极谱上用等魔鬼洋连续变化法和单纯形法测得络合物组成的摩尔比为ｎｓｃ＾３＋,ｎｃａ＾２＋;ｎＡＲＳ＝２：１：２。     

锆—钙—茜素S异多核络合物极谱吸附波的研究

报道了锆－钙－茜素Ｓ异多核络合物的形成及该异多核络合物极谱吸附波测定锆的最佳实验条件，用此法测定了矿石样品中的微量锆，并探讨了该极谱法的性质的电极反应机理，在单扫描示波极谱上用单纯形法和斜率比法测得该体系异多核络合物的组成比为：ｎｚｒ（Ⅳ）：ｎｃａ＾２＋；ｎＡＢＳ＝１：１：４．用分光光度法测定亦得到相同的结论。     

钍-镧(铈)-茜素S异多核络合物吸附波

极谱法测定钍已有一些报导。由于稀土元素与钍的性质十分相似,故常对钍的测定产生严重干扰。沈含熙等发现,利用轻、重稀土离子间形成异多核多元络合物的性质,可以提高显色效率。我们发现,当有茜素S存在时,钍与镧、铈等轻稀土离子能在单扫示波极谱上产生一特征的络合物吸附波,这极可能是由于形成了异多核多元络合物。在控制适当过量     

锡（Ⅱ）—1—苯基—3—甲基—4—苯甲酰基—吡唑啉酮—5—络合物吸附波的研究

在ｐＨ４．０的ＨＡｃ－ＮａＡｃ缓冲介质中，Ｓｎ（Ⅱ）与１－苯基－３－甲基－４－苯甲酰基－吡唑啉酮－５（ＰＭＢＰ）生成络合物，于－０．７４Ｖ（ｖｓ．ＳＣＥ）出现一灵敏的极谱峰。锡含量在４．２×１０－８ｍｏｌ／Ｌ～３．４×１０－６ｍｏｌ／Ｌ范围内与峰高呈线性关系，检出限为１．７×１０－８ｍｏｌ／Ｌ。用多种电化学方法研究了极谱波的性质及电极反应机理，证明该极谱波为络合吸附波，峰电流由中心离子Ｓｎ（Ⅱ）还原产生，络合物组成为Ｓｎ（Ⅱ）∶ＰＭＢＰ＝１∶１。试验了多种离子对峰电流的影响。方法已用于矿样中痕量锡的测定。     

钪－间氯偶氮安替比林络合物吸附波的研究

在ｐＨ４．３０的ＨＡｃ－ＮａＡｃ介质中，钪－间氯偶氮安替比林（ｍ－ＣＡＡ）－硫氰酸钾生成三元络合物，于－０．３５Ｖ（ｖｓ．ＳＣＥ）处出现一尖锐的极谱峰，峰电流与钪离子浓度在０．０２０～０．２０μｇ／ｍＬ范围内呈线性关系，检出限为０．０１０μｇ／ｍＬ．用多种电化学方法研究了极谱波的性质及电极反应机理．方法用于矿样中钪的测定，结果满意     

镉（Ⅱ）—7—碘—8—羟基喹啉—5—磺酸络合物吸附波的研究

在ｐＨ４．３的ＨＡｃ－ＮａＡｃ介质中，Ｃｄ（Ⅱ）与７－碘－８－羟基喹啉－５－磺酸（７－Ｉ－Ｈ２ＱＳ）生成络合物。有二苯胍存在下，于－０．６８Ｖ（ｖｓ．ＳＣＥ）产生一灵敏的极谱波，峰电流与Ｃｄ（Ⅱ）浓度在８．９×１０－９～２．２×１０－６ｍｏｌ／Ｌ浓度范围内呈线性关系。通过对该极谱波性质及反应机理的研究，证实其为络合物吸附波，络合比为１∶１，络合物带负电荷。方法用于铜矿中镉的测定，结果满意     

钪-茜素氨羧络合剂络合物极谱吸附波

在邻苯二甲酸氢钾和甲酸的混合缓冲底液 (pH 4.8)中 , 钪与茜素氨羧络合剂形成电活性络合物,在单扫描极谱上于-0.54 V(vs SCE)产生一灵敏的络合吸附波,其二阶导数峰高与钪的浓度在 4.0× 10-8～ 3.0× 10-6 mol/L范围内呈线性关系,检出限达 2.0× 10-8 mol/L。测定了络合物的组成,探讨了极谱波的性质和电极反应机理。方法用于矿物中微量钪的测定,结果令人满意。     

钪-茜素S络合物吸附波

姚修仁等发现,在氯化铵、铜铁试剂、二苯胍底液中,钪在单扫示波极谱上有灵敏的络合物吸附波。但钍、锆、铀及稀土等干扰严重。李南强等研究了钆-茜素S的络合物吸附波,由于介质为弱碱性,故所有稀土元素都能产生络合物吸附波。我们发现,在茜素S、邻苯二甲酸氢钾和氨基乙酸底液(pH3.6—4.1)中,钪在单扫示波极谱上有良好的络合物吸附波。用钛铁试剂可消除少量铁、稀土等的干扰,检测限达1×10~(-7)M,钪的浓度在2×10~(-7)—     

铋(Ⅲ)-槲皮素极谱络合吸附波及微量铋的测定

在ｐＨ＝３．８，０．４ ｍｏｌ／Ｌ的ＨＣＯＯＨＨＣＯＯＮａ缓冲溶液中，铋与槲皮素的络合物在单扫极谱仪上能形成灵敏的络合物吸附波。该波在Ｂｉ３＋离子浓度为４ × １０－８～６×１０－６ｍｏｌ／Ｌ范围内与波高 ｈｐ成正比关系，检出限达到１×１０－８ｍｏｌ／Ｌ。对电极反应的机理进行了研究。利用该极谱波测定了铅基轴承合金中的铋含量。     

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.