氟化钙增敏石墨炉原子吸收法测定人发和血清样品中痕量钼的研究

石墨炉原子吸收法测定生物样品中痕量钼时，用氟化钙作基体改进剂，可使钼的原子吸光度提高５．７倍，其特征量原来的４．２× １０＾－１１ｇ／１％吸收降低到５．１×１０＾－１２ｇ／１％吸收，测定下限为０．５５ｎｇ·ｍＬ＾－１，线性范围为０～１０００ｎｇ· ｍＬ＾－１． 对人发和牛血清标样中痕量钼测定。结果满意。     

偶合反应化学发光法测定痕量银的研究——K4Fe（CN）6—Luminol体系

将Ａｇ（Ｉ）催化Ｋ４Ｆｅ（ＣＮ）６的水合反应与Ｌｕｍｉｎｏｌ同Ｃｕ（ＣＮ）＾２－４的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到４．０×１０＾－１３ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１２～１．０×１０＾－６ｇ／ｍＬＡｇ对４×１０＾－１１ｇ／ｍＬＡｇ（Ｉ）溶液连续１１次测定的ＲＳＤ≤３．５％，用于环境水和岩矿中银的     

无机还原剂与光泽精化学发光反应的研究：Ⅲ.钒（Ⅱ）—光泽精体系的化…

本采用装有Ｊｏｎｅｓ柱的流动注射系统，研究了钒（Ⅱ）－光泽精体系的化学发光反应。在此基础上建立了痕量钒测定的新方法。方法的检出限３×１０＾－１０ｇ·ｍＬ＾－１；对于１．０×１０＾－７ｇ·ｍＬ＾－１钒标准溶液测定的相对标准偏差为２％（ｎ＝１１）；线性范围１．０×１０＾－９￣９．０×１０＾－５ｇ·ｍＬ＾－１，相关系数大于０．９９８０。该方法已用于水样中痕量钒的测定。对于反应机理，本也进行了探讨。     

测定钴的化学发光新体系

研究了新吖啶衍生物９，１０－二甲基吖啶氟磺酸盐的化学发光特性。建立了测定Ｃｏ６２＋的化学发光新体系。方法线性范围为１．０×１０＾－１０－１．０×１０＾－７ｇ／ｍＬ；检测限为５．０×１０＾－１１ｇ／ｍＬＣｏ＾２＋。测定５．０×１０＾－９ｇ／ｍＬＣｏ６２＋的相对标准偏差为６．０％。方法选择性好，用于自来水，江水，池塘水中痕量钴的测定，结果令人满意。     

氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒

本文研究了氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒的条件及应用。钒含量在０～６０ｎｇ／１０ｍＬ范围内与ｌｇ（Ａ＿０／Ａ）有良好的线性关系，检出限１．０×１０￣（－１１）ｇ／ｍＬ。方法简便快速，应用于水及食品中痕量钒测定，结果满意。     

偶合反应化学发光法测定痕量银的研究

本将Ａｇ（Ⅰ）催化Ｓ２Ｏ＾２－８氧化Ｍｎ（Ⅱ）生成ＭｎＯ＾－４的催化反应与ＬｕｍｉｎｏｌＭｎＯ＾－４－ＯＨ＾－的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到３．２×１０＾－１２ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１１－１．０×１０＾－５ｇ／ｍＬＡｇ，用于水样分析，结果较为满意。     

流动注射化学发光法测定甲氨蝶呤

研究了甲醛增强高锰酸钾与甲氨蝶呤的化学发光反应，由此建立了一种测定甲氨蝶呤的流动性注射化学发光分析法，方法的检出限为３．４×１０＾－９ｇ／ｍＬ，相对标准偏差为１．１％（２．０×１０＾－６ｇ／ｍＬ甲氨蝶呤，ｎ＝１１）线性范围为１．０×１０＾－８～１．０×１０＾－５ｇ／ｍＬ。该法已用于甲氨蝶呤针剂及片剂中甲氨蝶呤含量的测定。     

高磺酸钾—罗丹明6G催化荧光法测定超痕量钌

研究了在盐酸介质中,钌催化高碘酸钾氧化罗丹明６Ｇ的反应及动力学条件,建立了高灵敏测定超痕量钌的新方法。线性范围为０．２～１．０ｎｇ／２５ｍＬ,检出限为６．５×１０＾－１２ｇ／ｍＬ。方法已用于合成样中钌的测定。     

催化反应吸光光度法测定痕量银

研究了Ａｇ对亚铁氰化钾与邻菲罗啉显色反应的催化研究，建立了痕量银的催化吸光光度法。灵敏度为１．０×１０＾－３μｇ．ｍｌ＾－１，线性范围为０－０．４μｇ／２５ｍＬ。用于水样中痕量银的测定，结果满意。     

无机还原剂与光泽精化学发光反应的研究Ⅲ．钒（Ⅱ）－光泽精体系的化学发光反应

本文采用装有Ｊｏｎｅｓ柱的流动注射系统，研究了钒（Ⅱ）－光泽精体系的化学发光反应。在此基础上建立了痕量钒测定的新方法。方法的检出限３×１０￣（－１０）ｇ·ｍＬ￣（－１）；对于１．０×１０￣（－７）ｇ·ｍＬ￣（－１）钒标准溶液测定的相对标准偏差为２％（ｎ＝１１）；线性范围１．０×１０￣（－９）～９．０×１０￣（－５）ｇ·ｍＬ￣（－１），相关系数大于０．９９８０。该方法已用于水样中痕量钒的测定。对于反应机理，本文也进行了探讨。     

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%).     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

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.