表面活性剂增敏铍试剂Ⅱ荧光法测定痕量锰

在碱性条件下，Ｍｎ（Ⅱ）与铍试剂Ⅱ形成１；２的荧光络合物，其荧光峰为λｅｘ＝λｅｍ＝３６７／４６７（ｎｍ），表面活性剂十二烷基苯磺酸钠对体系具有强烈增敏作用，基于此建立了痕量锰的测定方法。本文研究了测定的最佳条件，即０．０１％铍试剂Ⅱ４．０ｍＬ，０．１ｍｏｌ／ＬＮａＯＨ６．０ｍＬ，１％ＳＤＢＳ ４．０ｍＬ，反应温度为９０℃，时间１０ｍｉｎ，线性范围为０－１６０μｇ／Ｌ，回归方程Ｘ（μｇ／Ｌ）＝２．     

火焰原子吸收法测定植物样品中硼与碘

将ＢＯ＾３－３转化为ＢＦ＾－４，ＩＯ＾－３转化为Ｉ＾－以Ｃｄ（ｐｈｅｎ）＾２＋３络合和硝基苯萃取，用火焰原子吸收法间接测定与碘，其特征浓度达０．０１６μｇ／ｍＬ１％Ａ和０．０２８μｇ／ｍＬ１％Ａ，在稻米等样品中作加标回收，硼回收率为９２．８－１０２．４％，碘为９７．２－１０６．７％。     

高碘酸钠-过氧化氢-盐酸黄连素化学发光体系的研究

１引言 盐酸黄连素是一种用于治疗肠道感染，毒性低、副作用小的天然药物。对盐酸黄连素的测定，化学发光法未见报道。本文发现，过氧化氢存在下，磷酸介质中盐酸黄连素与高碘酸钠反应产生强的化学发光。据此结合流动注射技术建立了在ＮａＩＯ４－Ｈ３ＰＯ４－Ｈ２Ｏ２－盐酸黄连素体系中测定盐酸黄连素的化学发光新方法。方法的检出限为 ３．８×１０－９ｇ／ｍＬ。线性范围是 １．０× １０－８－ ７．０ ×１０－６ｇ／ｍＬ。相对标准偏差为 ２．３％（ Ｃ８＝ １． ０ ×１０－６ｇ／ｍＬ； ｎ＝１１）。该法与药典方法对照，结果满意。…     

新—阶导数双峰光谱法解析及应用──测定NO_3~－和NO_2~－

本文通过对ＮＯ３－和ＮＯ２－的一阶导数光谱研究，提出利用它们各自导致光谱峰值的两种解析方法测定相互干扰的两组份含量，由于利用尽可能最大信息量和导数谱的特有功能，使测定ＮＯ３－和ＮＯ２－灵敏度分别为０．００５μｇ／ｍＬ、０．００９μｇ／ｍＬ（峰高－截矩比ｆ校正系数法）及０．００４μｇ／ｍｌ、０．００６μｇ／ｍＬ（双峰ｋ系组合导致法），线性范围皆为０～１．０μｇ／ｍＬ方法用于水样分析，结果令人满意。     

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。     

二溴羟基苯基荧光酮荧光猝灭法测定Br^—

本文报道了以二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）为指示剂，在阳离子表活性剂ＣＰＣ存在下荧光猝灭间接测定Ｂｒ＾－的新方法。在０．６ｍｏｌ／ＬＨ２ＳＯ４介质中，Ｂｒ＾－和ＢｒＯ３＾－反应生成Ｂｒ２，Ｂｒ２与ＤＢＨ－ＰＦ（λｅｍ＝５２０ｎｍ）生成红色化合物，使体荧光猝灭。Ｂｒ＾－含量在０．２５－６．２５μｇ／２５ｍＬ范围内有良好的线性关系，检测限为０．２５μｇ／２５ｍＬ。该法灵敏度高，选择性好，用于合成海     

用硫代米Chi酮光度法测定微量卤酸根离子的研究

在不同浓度盐酸溶液中,ＣｌＯ＾－３,ＢｒＯ＾－３,ＩＯ＾－３可分别与硫代米Ｃｈｉ酮,ＮＨ４ＳＣＮ形成蓝色梧合物,λｍａｘ为６２０ｎｍ。卤酸根测定的线性范围为ＩＯ＾＿３为０－３．０μｇ／１０ｍＬ,ＣｌＯ＾－３,ＢｒＯ＾＿３ｏ ０－４．０μｇ／１０ｍＬ。摩尔吸光系数分别为ε＝ＣｌＯ＾－３＝７．６７×１０＾４,εＢｒＯ＾－３＝９．９４×１０＾４,εＩＯ＾－３＝１．４５×１０＾５。本法灵敏,选择性好,操作     

二溴羟基苯基荧光酮荧光猝灭法测定Br~－

本文报道了以二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）为指示剂，在阳离子表面活性剂ＣＰＣ存在下荧光猝灭间接测定Ｂｒ￣－的新方法。在０．６ｍｏｌ／ＬＨ＿２ＳＯ＿４介质中，Ｂｒ￣－和ＢｒＯ反应生成Ｂｒ＿２，Ｂｒ＿２与ＤＢＨ－ＰＦ（λ＿（ｅｘ）＝４９５ｎｍ，λ＿（ｅｍ）＝５２０ｎｍ）生成红色化合物，使体系荧光猝灭。Ｂｒ￣－含量在０．２５～６．２５μｇ／２５ｍＬ范围内有良好的线性关系，检测限为０．２５μｇ／２５ｍＬ。该法灵敏度高，选择性好，用于合成海水样品中Ｂｒ￣－的测定，结果满意。     

新试剂N—间甲苯基—N′—（氨基对苯磺酸钠）硫脲（MMPT）的合成及其在…

本文合成新试剂Ｎ－间甲苯基－Ｎ′－（氨基对苯磺酸钠）硫脲（ＭＭＰＴ）经红外，紫外，核磁，元素分析等测试，确定其结构，研究测定了试剂与４０多种种离子的反应及其配合物的表观洋吸光系数，它可作为Ｃｕ＾２＋（ｍ＝０．０１５μｇ，ｃ＝０．５μｇ／ｍＬ），Ａｇ＾＋（ｍ＝０．１μｇ，ｃ＝３．３μｇ／ｍＬ）的新鉴定试剂和光度法测定Ｐｄ＾２＋（ε３０９．７＝６．３２×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，Ｐｔ（Ⅳ）     

用钼酸盐和罗丹明B连续光度法测定铈和钪

聚乙烯醇存在下，铈或钪钼杂多酸与罗丹明Ｂ（ＲＢ）形成离子缔合物，最大吸收均位于５７０ｎｍ，摩尔吸光系数分别为１．１６×１０＾６和５．６２×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，ｃｍ＾－１，０－１．２μｇ／２５ｍＬＣｅ和０－２．０μｇ／ｍＬＳｃ服从比耳定律，检测限１．５ｎｇ／ｍＬＣｅ（ｎ＝１０）和１．１ｎｇ／ｍＬＳｃ（ｎ＝９）。缔合物的摩尔比为Ｃｅ：ｍＯ：ＲＢ＝１：６：３和 Ｓｃ：Ｍｏ：ＲＢ＝１：１     

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.     

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.     

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.     

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.