酞菁锰—表面活性剂薄膜电极的电化学表征及其对三氯乙酸的电化学催 …

将酞菁锰（ＭｎＰｃ）掺入阳离子表面活性剂双十二烷基二甲基溴化铵（ＤＤＡＢ）的氯仿溶液，并涂布于热解石墨电极表面，待氯仿挥发后即制得ＭｎＰｃ－ＤＤＡＢ薄膜电极，循环伏安实验表明，在ＫＢｒ溶液中，该薄膜电极有两对还原氧化峰，第一对峰的Ｅｐｃｔ＝－０．２７Ｖ，Ｅｐａ１＝０．０１Ｖ；第二对峰的Ｅｐｃ２＝－０．７６Ｖ，Ｅｐａ２＝－０．６２Ｖ（ｖｓ．ＳＣＥ）。本文着重探讨了第二对峰的电化学行为，估计了该体系电     

酞菁镍—表面活性剂薄膜修饰电极及其催化性能的研究

将酞菁镍（ＮｉＰｃ）掺入阳离子表面活性剂双十二烷基二甲基溴化铵（ＤＤＡＢ）的氯仿溶液中，并涂布于热解石墨电极表面，待氯仿挥发后制得ＮｉＰｃ－ＤＤＡＢ薄膜电极。循环伏安实验表明，在ＫＢｒ溶液中，该薄膜电极有两对良好且稳定的还原氧化峰，第一对峰的Ｅｐｃ１＝－０．６４Ｖ，Ｅｐａｌ＝－０．６０Ｖ（ｖｓ．ＳＣＥ）；第二对峰的Ｅｐｃ２＝－０．８４Ｖ，Ｅｐａ２＝－０．８０Ｖ。本文着重探讨了第二对峰的电化学行为，     

四磺酸酞菁铜—DDAB表面活性剂薄膜电极对卤代乙酸的电化学催化

四磺酸酞菁铜阴离子（ＣｕＰｃＴｓ＾４－）在水溶液中可借助离子交换进入阳离子表面活性剂双十二烷基二甲基溴化铵（ＤＤＡＢ）薄膜电极，从而形成ＣｕＰｃＴＳ＾４－－ＤＤＡＢ薄膜电极，循环伏安实验表明，在ＫＢｒ溶液中，该薄膜电极有一对良好的还原氧化峰，阴阳极峤电位分别为－０．７８Ｖ和－０．６５Ｖ（ｖｓ．ＳＣＥ）．探讨了该薄膜电极的电化学行为，特别是对其各种卤代乙酸的电化学催化，对其机理进行了推测。     

硫堇衍生化自组装膜修饰金电极的电化学性质及其对抗坏血…

将硫堇共价键合到自组装在金电极表面的半胱胺单分子层上，制成了衍生化自组装单分子膜修饰电极，并用电化学方法研究了它的电化学性质，循环伏安图显示其在ｐＨ＝７．７的磷酸盐缓冲液中，于－０．４５～＋０．５０Ｖ（ｖｓ．ＳＣＥ）范围内有２对氧化还原峰，峰电位分别为Ｅｐａ＝２１４ｍＶ，Ｅｐｃ＝８２ｍＶ，Ｅ＾２ｐａ＝－７５ｍＶ，Ｅ＾２ｐｃ－－１６０ｍＶ（ｖｓ．ＳＣＥ），ｐＨ在５．０～９．０范围内，峰１有２个质子参     

磷钼杂多酸-L-半胱氨酸自组装超分子膜电极对亚硝酸根电催化还原的研究

制备了磷钼杂多酸－Ｌ－半胱氨酸自组装超分子膜电极（Ｐ２Ｍｏ１８－Ｌ－Ｃｙｓ／Ａｕ）。采用水平衰减全反射（ＡＴＲ－ＦＴＩＲ）光谱表征了膜的组成。研究了该膜电极的电化学性质，发现它在１．０ ｍｏｌ／Ｌ　Ｈ２ＳＯ４溶液中，于０．０～０．７Ｖ（ｖｓ．ＳＣＥ）间ＣＶ扫描出现两对稳定、可逆的氧化还原峰，其中峰电位分别为Ｅｍ１＝０．３３４ Ｖ，Ｅｍ２＝０．１８８Ｖ，对应着Ｐ２Ｍｏ１８Ｏ_(６２)~(６－)的两步２电子－２质子反应；计时库仑法计算了薄膜内的电子传递系数Ｄ为５．０１ × １０~（－８）ｃｍ２·ｓ～（－１）。该膜电极对酸性溶液中的ＮＯ_２~－有明显的电催化还原作用，初步探讨了电催化机理。用差分脉冲伏安法（ＤＰＶ）测定其还原峰电流与ＮＯ_２~－的浓度在２．０ ×１０~（－６）～２．０ × １０~（－４）ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系数为０．９９５３，检测限５．０×１０~（－７）ｍｏｌ／Ｌ。该电极用于模拟水样中ＮＯ_２~－的测定，结果满意。     

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     

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     

头孢唑啉降解产物在银亚微盘电极上的电化学行为及其测定

基于头孢唑啉在 ０．１０ｍｏｌ／Ｌ ＮａＯＨ溶液中水浴降解产物中含有巯基（－ＳＨ），在 ｐＨ ５．０ＮａＡｃ－ＨＡｃ介质中，于银亚微盘电极上产生一灵敏的吸附伏安氧化还原峰，其峰电位分别为 Ｅｐａ＝－０．５３０Ｖ和 ＥＰｃ＝－０．４００Ｖ。动力学研究表明：电极反应的电子转移数为０．９１，表观电子传递速率为ｋｓ＝０．１０ｓ－１，峰电流与头孢唑啉浓度在１．０×１０－６～５０×１０－１ｍｏｌ／Ｌ范围内呈良好的线性关系。方法可应用于人工合成样品头孢啉的检测。     

硼掺杂多晶金刚石薄膜电极的电化学特性

用循环伏安法和恒电位法研究了硼掺杂多晶金刚石薄膜电极（ＤＦＥ）的若干电化学特性。电极面积４×４ｍｍ＾２。在０．１ｍｏｌ／Ｌ ＫＣｌ，ＮａＮＯ３，ＮａＯＨ和ＫＨ２ＰＯ４＋Ｎａ２ＨＰＯ４（ｐＨ＝６．８６）电解质溶液中电势窗口均为－５００￣＋８００ｍＶ；而在０．１ｍｏｌ／Ｌ ＨＣｌ和Ｈ２ＳＯ４溶液中电势窗口为－２００￣＋１１００ｍＶ．Ｋ３Ｆｅ（ＣＮ）６的氧化峰电位为＋５００ｍＶ，与Ｐｔ电极测量相同；校正     

脱氧核糖核酸变性和损伤的吸附伏安法研究

本文用汞电极（ＨＭＤＥ）二次导数阴极吸附伏安（ＳＤ－ＡｄＣＳＶ）和碳电极（ＧＣＥ、ＣＰＥ）导数循环伏安（ＦＤ－ＣＶ）法研究了核酸受热、紫外线、超声波和丝裂霉素Ｃ（ＭＭＣ）作用下的变性作用。在０．１ｍｏｌ／Ｌ（Ｋ２ＨＰＯ４＋ＫＨ２ＰＯ４）－０．１ｍｏｌ．Ｌ ＮａＣｌ（ｐＨ７．０）底液中，吸附的单股（ｓｓ－）和双螺旋（ｄｓ－）ＤＮＡ分别在ＨＭＤＥ上得到特征还原峰Ｐ３和Ｐ２，和在碳电极上得到氧化峰Ａ。物     

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.     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.