Fe（Ⅲ）—TEA—5—Br—PADAP—H2O2体系中催化波的研究及其应用

在０．２ｍｏｌ·Ｌ＾－１ＮＨ４Ｃｌ－ＮＨ３·Ｈ２Ｏ底液中，（ｐＨ为９．２６），得到一个极为灵敏的Ｆｅ（Ⅲ）－ＴＥＡ－５－Ｂｒ－ＰＡＤＡＰ－Ｈ２Ｏ２配合吸附催化波，其峰电位为－０．７１Ｖ（ｖｓ．ＳＣＥ）。铁浓度在１．８×１０＾－１０￣５．４×１０＾－６ｍｏｌ·Ｌ＾－１范围内与二阶导数波高呈线性关系。对该极谱波的性质进行了研究，证明是一种配合吸附催化波，并成功地应用于各类水样，钒催化剂中微量或痕量铁的     

二溴羟基苯基荧光酮—乳化剂OP荧光熄灭法测定微量铬（Ⅵ）

本文基于Ｃｒ（Ⅵ）－二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）－ＯＰ体系的荧光熄灭效应，提出一种测定痕量铬（Ⅵ）的新荧光方法。在ｐＨ２．４－４．１的ＨＣｌ－ＮａＡｃ缓冲介质和ＯＰ存在下，Ｃｒ（Ⅵ）与ＤＢＨ－ＰＦ形成１：２的橙红色络合物，络合物的最大激发发工和发射波长分别是３６５ｍｍ和５２８ｎｍ。铬（Ⅵ）量在０．０５－１．５μｇ／２５ｍｌ范围内与△Ｆ呈线性关系，检测限是２．０ｎｇ／ｍｌ。方法用于电镀废液，废     

铬（VI）与5—溴水杨基荧光酮的显色反应及应用

本文研究了Ｃｒ（Ⅵ）与５－溴水杨基荧光酮（５－Ｂｒ－ＳＡＦ）的显色反应。在ｐＨ６．０ＫＨ２ＰＯ４－ＮａＯＨ缓冲溶液中，Ｃｒ（Ⅵ）与５－Ｂｒ－ＳＡＦ、ＣＴＭＡＢ形式稳定的三元络合物，其最大吸收波长为５７２ｎｍ，表观摩尔吸光系数为１．４２×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１。Ｃｒ（Ⅵ）浓度在０￣２．５μｇ／１０ｍＬ间服从比耳定律。用此法测定了环境水样中微量Ｃｒ（Ⅵ），获得满意结果。     

示波极谱测定天然水,食品和生物样品中痕量锡

在Ｈ２ＳＯ４－ＨＣｌＯ４－ＮａＢｒ－（ＮＨ４）２ＶＯ３的体系中，Ｓｎ（Ⅳ）在－０．６０Ｖ左右产生一个非常灵敏的极谱催化谱，Ｓｎ（Ⅳ）浓度在０．８－１６０ｎｇ．ｍＬ＾－１之间与峰电流成线性关系，检测限为０．２６ｎｇ．ｍＬ＾－１。该法应用于天然水、食品和生物样品中痕量锡的测定，结果令人满意。     

流动注射化学发光同时测定废水中的三价铬和六价铬

首次将镀铜锌粒作成优良的还原柱，在线还原Ｃｒ（Ⅵ）成Ｃｒ（Ⅲ），以鲁米诺－Ｈ２Ｏ２（ＫＢｒ）体系流动注射化学发光同时测定废水中两种价态的铬。分析速率为６０试样／ｈ；线性范围为１．０×１０＾－５－１．０×１０＾－９ｍｏｌ／Ｌ；测Ｃｒ（Ⅲ）及Ｃｒ（Ⅵ）的相对标准偏差（ｎ＝６）分别为０．３７％－４．０％及１．２％－４．４％；测定Ｃｒ（Ⅲ）的检出限２．３×１０＾－１１ｍｏｌ／Ｌ。测定结果与标准方法无显差     

N—取代三氯乙酰胺合成N,N“—多亚甲基双（N‘—（4—氯苯基）脲

通过Ｎ－取代三氯乙酰胺与不同的脂肪二胺反应，合成了５种新的Ｎ，Ｎ”－多亚甲基双（Ｎ’－（４－氯苯基）脲（ＡｒＮＨＣＯＮＨ（ＣＨ２）ｎＮＨＣＯＮＨＡｒ，ｎ＝２～６，Ａｒ＝４－ＣｌＣ６Ｈ４）其结构经元素分析，ＨＮＭＲ和ＩＲ证实。     

钴（Ⅱ）—β—巯基丙酸—NaNO2体系的极谱化波研究

在ｐＨ３．８的Ｈ２ＳＯ４－ＮＨ４Ａｃ介质中，Ｃｏ（Ⅱ）－β－巯基丙酸（ＭＰＡ）－ＮａＮＯ２体系产生－灵敏的极谱催化波，峰电位在－０．８４Ｖ（ｖｓ．ＳＣＥ）钴浓度在０．０２～１００ｎｇ／ｍＬ范围内与峰电流呈线性关系，检出限为０．０１ｎｇ／ｍＬ。本文对极谱波的性质和机理进行了初步探讨，本法用于土壤中总钴和有效钴的测定，结果满意。     

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     

化学修饰石墨探针预富集—石墨炉原子吸收法测定Cr（Ⅵ）和Cr（Ⅲ）

本将化学修饰石墨探针选择性预分离富集和石墨炉探针原子化学测定的高灵敏度结合起来，建立了用ＴＯＰＯ修饰的石墨探针络合富集Ｃｒ（Ⅵ），Ｎａｆｉｏｎ修饰的石墨探针交换富集Ｃｒ（Ⅲ）的双饰石墨探针顺序分富集，石墨炉探针原子化法测定水体中Ｃｒ（Ⅵ）和Ｃｒ（Ⅲ）的方法。Ｃｒ（Ⅲ）的检出限为１．０３ｎｇ／ｍＬ，线性范围为０－５１ｎｇ／ｍＬ。Ｃｒ（Ⅵ）的检出限为０．３７ｎｇ／ｍＬ，线性范围为０－８１ｎｇ／ｍＬ。     

微分电位溶出法测定人发中铜铅镉锌的研究

本文报道了０．００２５ｍｏｌ·Ｌ￣（－１）ＨＣｌ－０．２ｍｏｌ·Ｌ￣（－１）ＮＨ＿（４）Ｃｌ底液中连续测定人发中铜、铅、镉、锌的微分电位溶出法。四元素峰电位分别为－０．２０Ｖ，－０．４６Ｖ，－０．６７Ｖ，一１．０２Ｖ（ＳＣＥ），峰形好，灵敏度高，干扰少，测定发样相对标准偏差≤４．３％，回收率为９７．６％～１０４．６％。并对ＨＮＯ＿３－ＨＣｌＯ＿４和ＨＮＯ＿（３）Ｈ＿（２）Ｏ＿２消化发样进行了比较。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.