硅钼杂多阴离子薄膜修饰电极线性扫描伏安法测定黑液中要溶性硅

本报导了以玻碳电极为基体的１∶１２硅钼杂多阴离子薄膜化学修，铈电极的制备及其电化学特性。并应用于导数伏安法测定。在４．０×１０＾－３ｍｏｌ／Ｌ９ＮＨ４）６Ｍｏ７Ｏ２４－６６．８×１０＾－２ｍｏｌ／ＬＮａ３Ｃｉｔ－０．４８ｍｏｌ／Ｌ ＮＨＯ３体系中，硅浓度在８．３×１０＾－７～１．７×１０＾－３ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定     

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。     

氨基萘磺酸盐无保护流体室温磷光的取代基位置效应

以ＴＩＮＯ３作重原子微扰剂,Ｎａ２ＳＯ３作化学除氧剂,在无需加入任何保护介质条件下,仅需仪器光源适当照射,１－氨基４－萘磺酸盐、１－氨基５－萘磺酸盐、２－氨基１－萘磺酸盐水溶液均能产生强而稳定的室温磷光信号（ＲＴＰ）。３种氨基萘磺酸盐浓度分别在４．０×１０＾－８￣１．２×１０＾－５ｍｏｌ／Ｌ;１．２×１０＾－６￣１．６×１０＾－５ｍｏｌ／Ｌ;１．６×１０＾－７￣８．０×１０＾－６和８．０×１０＾－     

一种基于形成杂多核络合物的荧光增敏效应的研究：Ⅲ.锰（Ⅱ）,钴（…

本研究了Ｍｎ＾２＋和Ｃｏ＾２＋对７－（８－羟基－３，６－二磺基萘偶氮）－８－羟基喹啉－５－磺酸－硼砂反应体系的混合荧光增敏作用。实验条件下，荧光增敏强度满足线性加和关系的范围是：Ｍｎ＾２＋浓度０￣２．９×１０＾－７ｍｏｌ／Ｌ；Ｃｏ＾２＋浓度０￣８．８～１０＾－７ｍｏｌ／Ｌ；总浓度不超过１．０×１０＾－６ｍｏｌ／Ｌ。检出限量为Ｍｎ＾２＋４．５×１０＾－９ｍｏｌ／Ｌ和Ｃｏ＾２＋１．４×１０＾－８ｍｏ     

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。     

铋－2，3，4－三羟基－4′－磺基－偶氮苯配合物吸附波的研究

在０．０６ｍｏｌ／Ｌ柠檬醚钠－０．００３ｍｏｌ／ＬＨＣ１（ｐＨ６．５）介质中，２，３，４－三羟基－４′－磺基－偶氮苯和铋产生灵敏的单扫描极谱导数峰，铋含量在０～６．７×１０￣（－６）ｍｏｌ／Ｌ范围内与波高成线性关系，检测限２．４×１０￣（－８）ｍｏｌ／Ｌ。用提出的方法测定了锡中的铋，并对反应机理进行了研究。     

单缺位Dawson型磷钨杂多酸掺杂聚吡咯的过氧化氢传感器研究

在金电极上，用电化学方法将单缺位Ｄａｗｓｏｎ型磷钨杂多酸盐ａ２－Ｋ１０Ｐ２Ｗ１７Ｏ６１１５Ｈ２Ｏ的阴离子（Ｐ２Ｗ１７）掺杂到聚吡咯（ＰＰｙ）薄膜中，制成ＰＰｙ／Ｐ２Ｗ１７／Ａｕ的Ｈ２Ｏ２传感器。研究了它对 Ｈ２Ｏ２电还原过程的催化机理．其 ｉｐｅ与 ＣＨ２Ｏ２在 ６．０× １０－５～８． ８×１０－４ ｍｏｌ／Ｌ和８．８×１０－４～６．０×１０－３ｍｏｌ／Ｌ范围内呈良好的线性关系，检测下限为４．０×１０－５ｍｏｌ／Ｌ。用于模拟水样中Ｈ２Ｏ２的测定，结果较满意．     

硅钼杂多阴离子薄膜修饰电极的研究和应用—线性扫描伏安法测定水中可溶性

本研究了以玻碳电极为基体的１：１２硅钼杂多酸根修饰电极的制备及其电化学行为，将１２－ＭＳＡ电极应用于线性扫描伏安法测定天然水中可溶性硅酸盐，结果满意，硅浓度在８．０×１０＾－７－１．７×１０＾－３ｍｏｌ／Ｌ，相对标准偏差（ｎ＝７）为１．８５％，加标回收率为９８．２％－１０３．６％，ＳｉＭｏ１２电极具有优良的选择性和稳定性。     

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     

哌仑西平的单扫描示波极谱法测定

本报道一种测定哌仑西平的单扫描示波极谱法，在０．１ｍｏｌ／ＬＮＨ４Ｃｌ－ＮＨ３．Ｈ２Ｏ（ｐＨ８．０±０．１）缓冲液中，哌仑西平有一极谱还原波，其峰电位为－１．５１Ｖ（ｖｓ．ＳＣＥ），其一阶导数峰高与哌仑西闰浓度在６．６×１０＾－７－４．６×１０＾－６ｍｏｌ／Ｌ（ｒ＝０．９９８１）和６．６×１０＾－６－１．６×１０＾－５ｍｏｌ／Ｌ（ｒ＝０．９９９１）范围内有线性关系，检测限为３．４×１０－７ｍｏｌ     

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%.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.     

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.     

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.