核黄素丁酸酯在汞电极上的吸附伏安特性及其反应速率常数的测定

循环伏安法表明,在ＮａＯＨ底液中核黄素丁酸酯（ｒｉｂｏｆｌａｖｉｎｅ　ｔｅｔｒａｂｕｔｙｒａｔｅ,ＲＴ）在汞电极上有一对氧化还原峰,其峰电位Ｅｐｃ＝Ｅｐａ＝－０．６４Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）。本文用多种电化学手段对ＲＴ的吸附特性进行了较详细的研究。吸附粒子为ＲＴ中性分子,测得ＲＴ在汞电极上的饱和吸附量为５．４２×１０－１１ｍｏｌ／ｃｍ２,每个ＲＴ分子所占电极面积为３．０６ｎｍ２,ＲＴ在悬汞电极上的吸附符合Ｆｒｕｍｋｉｎ等温式。测得吸附系数β＝４．６×１０５,吸引因素γ＝ １． １０,吸附自由能△Ｇ°＝－ ３２． ３０ ｋＪ／ｍｏｌ。本文还用循环伏安法研究了ＲＴ的电极反应动力学性质,测定了其在汞电极上的反应速率常数。     

卡托普利在汞电极表面的电化学行为

用循环伏安法、阴极溶出伏安法和电毛细管曲线测量等方法研究了卡托普利在汞电极表面的电氧化机理。实验结果表明,酸性溶液中卡托普利比较稳定,而在中、碱性溶液中卡托普利不稳定。在酸性溶液中有质子参与电极过程,卡托普利在电极表面发生单电子转移,生成汞（Ｉ）－硫化合物,该化合物在电极表面有强吸附,并进一步转化成汞（Ⅱ）－硫化合物。按照实验结果,计算了卡托普利的扩散系数和电极反应速率常数,提出了卡托普利电化学氧     

吸附溶出伏安法测定血浆和尿液中的尿酸

在Ｂｒｉｔｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲体系中，研究了尿酸的伏安行为，实验表明，尿酸在悬汞电极上具有吸附行为，并于－０．０８Ｖ产生灵敏的峰电流。该法可用于尿液和血浆中尿酸的测定，回收率为９５－１０５％。     

氯氮平的吸附伏安行为

在０．１ｍｏｌ／ＬＮＨ４Ａｃ（ｐＨ７．８）底液中，氯氮平（ＣＬＰ）在汞电极上有一线性扫描还原峰，Ｅｐｃ＝－１．３４Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）．该峰具有明显的吸附性，吸附粒子为ＣＬＰ中性分子．测得ＣＬＰ在汞电极上的饱和吸附量为２．７×１０－１０ｍｏｌ／ｃｍ２，每个ＣＬＰ分子所占电极面积为０．６２ｎｍ２，ＣＬＰ在悬汞电极上的吸附符合Ｆｒｕｍｋｉｎ等温式．测得吸附系数β＝６．２８×１０５，吸引因素γ＝０．７５，电子转移数ｎ为２，不可逆吸附的转移系数α为０．５３．探讨了ＣＬＰ在汞电极上的还原机理，并建立了吸附溶出伏安法测定ＣＬＰ的最佳条件，检测限为８．０×１０－９ｍｏｌ／Ｌ．     

噻利洛尔的吸附伏安行为

在ＮＨ３－ＮＨ４Ｃｌ底液中,噻利洛尔在汞电极上有一线性扫描还原峰,电位Ｅｐｃ＝－１．３１Ｖ（ｖｓ,Ａｇ／ＡｇＣｌ）,该峰具有明显的吸附性。当ＣＥＬ浓度较小时,扫描较快,搅拌富集时间较长时,电极反应完全为吸附态的ＣＥＬ的还原所控制,吸附粒子为ＣＥＬ中性分子,测得ＣＥＬ在汞电极上的饱和肿附量为１．０３×１０＾－１０ｍｏｌ／Ｌ,每个ＣＥＬ分子所占电极面积为１．５７ｎｍ＾３,ＣＥＬ在悬汞电极上的吸附符合Ｌ     

铕-维生素B6及铕-维生素B6-甘氨酸配合物的伏安法研究

用循环伏安法研究了在汞膜玻碳电极上Eu^3 与维生素B6（VB6）及Eu^3 与VB6，甘氨酸（Gly)的电化学行为，结果表明：在适宜的酸度下，由于VB6，VB6－Gly在汞膜电极上的吸附，二元，三元配合物能迅速生成，毛细管电泳法验证了此结构，同时观察并探讨了配合物在碱性，中性、酸性介质中的电化学行为的差异及机制。     

芬太尼衍生物DMPPE的电化学行为和吸附伏安性质

本文探讨了麻醉镇痛药物芬在尼的衍生物双－Ｎ－（１－苯甲基－４－哌啶基）－草酰对甲氧基苯基胺（ＤＭＰＰＥ）在汞电极上的电化学行为。循环伏安法表明，在ＮａＯＨ底液中，ＤＭＰＰＥ可在汞电极上还原，Ｅｐｃ＝－１．５３Ｖ（ｖｓ．饱和Ａｇ／ＡｇＣｌ），并可吸附于电极表面。着重考察了ＤＭＰＰＥ的吸附特性，认为吸附型体是ＤＭＰＰＥ中性分子。利用吸附伏安法进行微量ＤＭＰＰＥ的测定，在最佳条件下，最低检测限可在４．０     

痕量苯胺的单扫描极谱法测定

１引言环境水样中痕量苯胺的测定多采用偶氮化色法，利用苯胺偶氮盐与羟基化合物偶合生成的偶氮化合物的吸附波间接测定苯胺的方法已有报道。作者观察到，在氨水－氯化铵介质中，８－羟基喹啉与苯胺重氮盐偶合生成的偶氮化合物在滴汞电极上于－０．７４Ｖ（ｖｓ．ＳＣＥ）处产生－灵敏的导数极谱波，苯胺浓度在０．００８～１．４０ｍｇ／Ｌ范围内与波高呈良好的线性关系，可用于痕量苯胺的测定，方法用于污水中痕量苯胺的测定，结果令人满意。２实验部分２．１仪器与试剂ＪＰ－２型示波极谱仪；三电极体系导数档；苯胺标准溶液：１００与１…     

卡可西灵在汞电极上的电化学行为和吸附特性

在ＨＡｃ－ＮａＡｃ底液中，卡可西灵在汞电极上有两个还原峰，第一峰峰电位Ｅｐｃ１＝０．０４Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ），为２电子转移的可逆过程；第二峰峰电位Ｅｐｃ２＝－０．３９Ｖ，为４电子转移的不可逆过程，第二峰具有明显的吸附性。本文探讨了该吸附特性，认为吸附型体为中性分子，属于不可逆吸附体系。测得其电极反应动力学参数αｎα和卡可西灵在汞电极上的饱和吸附量，估计了每个卡可西灵分子所占的面积，建立了测定     

甘草酸的电化学行为研究

用循环伏安法、单扫描示波极谱法研究了甘草酸（ｇｌｙｃｙｒｒｈｉｚｉｃ，ＧＡ）在汞电极上的电化学行为及反应机理．证明甘草酸在ｐＨ＝４～１２的缓冲溶液（Ｈ３ＢＯ３＋Ｈ３ＰＯ４＋乙酸＋ＮａＯＨ）中有吸附峰，且示波极谱导数峰值与甘草酸浓度在８．３×１０－５～１．２×１０－６ｍｏｌ／Ｌ范围内成正比，使用悬汞电极（ＨＭＤＥ）线性扫描伏安法可使检测下限达２．４×１０－６ｍｏｌ／Ｌ．根据实验结果首次提出了甘草酸在汞电极上的反应机理．该机理同时被紫外光谱证明，得到合理解释     

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.