对偶氮苯重氮氨基偶氮苯磺酸与铊显色反应的研究

本研究了在ＮＨ３－ＮＨ４ＣＬ介质和ＴｒｉｔｏｎＸ－１００存在下，题示试剂与Ｔｌ（Ⅲ）的显色反应。试剂与Ｔｌ（Ⅲ）生成的红色配合物最大的吸收波长位于５２２ｎｍ处，摩尔吸光系数为１．３×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，Ｔｌ（Ⅲ）在０￣３５μｇ／２５ｍＬ范围内遵守比耳定律。方法应用于合成水样中铊的直接测定，９次测定的相对标准偏差分别为２．１％和２．８％。     

试剂4—（2—苯并咪唑偶氮）—间苯二酚与铀（Ⅵ）显色反应的研究与应用

研究了新显色剂４－（２－苯并咪唑偶氮）－间苯二酚（ＢＩＡＲ）在ＴｒｉｔｏｎＸ－１００存在下与铀（Ⅵ）的显色反应，在ｐＨ８．０的三乙醇胺缓冲介质中，试剂与铀（Ⅵ）形成２＋１的红色配合物，最大吸收峰位于５４０ｎｍ处，表观摩尔吸光系数为３．１６×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。铀量在０～３．２０μｇ／ｍＬ范围内符合比尔定律。经ＴＢＰ萃取色层分离后，用于岩石矿物中微量铀的测定，结果令人满意     

水杨酸酯—Triton X—100—镥（Ⅲ）（钆（Ⅲ））增敏体系荧光法测定铽和镝

１引言作者等曾报道水杨酸苯酯－ＴｒｉｔｏｎＸ－１００－Ｇｄ３＋增敏体系荧光法测定Ｔｂ３＋。为了进一步提高测定的灵敏度并探讨同时测定Ｄｙ３＋的可能性，本文探讨了乙、丁、戊酯等烷基酯对测定的影响。结果表明，丁酯体系的灵敏皮最高，在该体系中Ｄｙ３＋的特征荧光也明显加强，在Ｌｕ３＋共存下Ｔｂ３＋、Ｄｙ３＋的检测限分别达到０．２和８．０μｇ／Ｌ，对Ｔｂ３＋而言，灵敏度较苯酯－Ｇｄ３＋增敏体系提高了１０倍。２实验部分２．１试剂与仪器１ｇ／ＬＴｂ３＋、Ｄｙ３＋标准溶液；３．５×１０－２ｍｏｌ／Ｌ水杨酸酯（乙、…     

新显色剂1-(2.4-二硝基苯)-3-(2-噻唑)-三氮烯的合成及与汞的显色反应研究

报道了新显色剂１－（２．４－二硝基苯）－３－（２－噻唑）－三氮烯的合成及其与Ｈｇ（Ⅱ）的显色反应。实验表明，在非离子表面活性剂ＴｒｉｔｏｎＸ－１００存在下，于ｐＨ１１．７５的三酸缓冲介质中，试剂与Ｈｇ（Ⅱ）能生成蓝绿色配合物，最大吸收波长位于６９０ｎｍ处，试剂的最大吸收波长位于４１０ｎｍ处，对比度高达２８０ｎｍ，其配合比为１∶２，表观摩尔吸光系数为１．１×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｈｇ（Ⅱ）含量在０～１８μｇ／２５ｍＬ范围内符合比耳定律。测定了废水中汞的含量，结果令人满意。     

苯并噻唑重氮氨基偶氮苯与汞（Ⅱ）的显色反应及其应用

报道了新试剂苯并噻唑重氮氨基偶氮苯的合成及其与汞（Ⅱ）的显色反应，在ＴｒｉｔｏｎＸ－１００存在下弱碱性介质中，试剂与汞形成２：１的橙红色络合物，最大吸收波长位于５２０ｎｍ处，表观摩尔吸光系数为１．５１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。汞量在０～１．２ｍｇ／Ｌ范围内遵守比尔定律，直接应用于废水中微量汞的测定，结果满意。     

桑色素荧光光度法测定二氯化双(丁氧羰乙基)锡

在ｐＨ３．０的ＨＡｃ－ＮａＡｃ缓冲溶液中和有Ｔｒｉｔｏｎ Ｘ－１００存在下,二氯化双（丁氧羰乙基）锡（简写为Ｒ２ＳｎＣｌ２）与桑色素形成１：１的荧光络合物。络合物的激发波长和发射波长分别为４４３．２ｎｍ和５１４。４ｎｍ。Ｒ２ＳｎＣｌ２中的Ｓｎ浓度在０￣３．０ｍｇ／Ｌ范围内,与络合物荧光强度呈线性关系。方法检出限为７．８１μｇ／Ｌ Ｓｎ,用于ＰＶＣ中间产品和污水中Ｒ２ＳｎＣｌ２的测定,结果满意,相对     

2-羟基-3-羧基-5-磺酸基苯基重氮氨基偶氮苯与铊反应的分光光度法研究

于ｐＨ１０．０～１１．０的ＮＨ３－ＮＨ４Ｃｌ缓冲介质中，在ＴｒｉｔｏｎＸ－１００存在下，铊（Ⅲ）与２－羟基－３－羧基－５－磺酸基苯基重氮氨基偶氮苯（ＨＣＳ－ＤＡＡ）形成组成比为１∶３的红色配合物，其最大吸收波长和对比度分别为５１０ｎｍ和８０ｎｍ，表观摩尔吸光系数为１．５２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，线性范围为０～０．７０ｍｇ／Ｌ，室温下显色反应立即完成，配合物至少稳定２ｈ。方法用于水样、烟叶和煤灰中痕量铊的分析，回收率为９０．０％～１０１．４％，５次测定的相对标准偏差不大于４．６％。     

非离子表面活性剂层状液晶的结构与增溶作用

相行为研究表明，与ＴｒｉｔｏｎＸ－１００／Ｃ＿６Ｈ＿６／Ｈ＿２Ｏ体系相比，ＴｒｉｔｏｎＸ－１００／Ｃ＿（１０）Ｈ＿（２１）ＯＨ／Ｈ＿２Ｏ体系更易于生成层状液晶，并更为稳定，小角Ｘ－射线衍射表明；ＴｒｉｔｏｎＸ－１００／Ｃ＿（１０）Ｈ＿（２１）ＯＨ／Ｈ＿２Ｏ体系层状液晶中，Ｃ＿（１０）Ｈ＿（２１）ＯＨ与ＴｒｉｔｏｎＸ－１００交替排列于两亲双层中，Ｃ＿（１０）Ｈ＿（２１）ＯＨ／ＴｒｉｔｏｎＸ－１００重量比增加，两亲双层厚度ｄ＿０值不变。以Ｃ＿６Ｈ＿６代替Ｃ＿（１０）Ｈ＿（２１）ＯＨ后，Ｃ＿６Ｈ＿６存在于两亲双层的油层和渗入ＴｒｉｔｏｎＸ－１００分子链尾周围，使得溶剂渗透率减少，并且Ｃ＿６Ｈ＿６／ＴｒｉｔｏｎＸ－１００增加，ｄ＿０值增加。     

新显色剂4-甲基-2-磺酸基苯基重氮氨基偶氮苯的合成及与镉的显色反应研究

报道了新显色剂４－甲基－２－磺酸基苯基重氮氨基偶氮苯的合成及其与Ｃｄ（Ⅱ） 的显色反应。实验表明,在非离子表面活性剂Ｔｒｉｔｏｎ Ｘ－１００存在下,于ｐＨ １０．８ 的氨水－氯化铵缓冲介质中,试剂与Ｃｄ（Ⅱ） 形成３∶１ 的红色络合物,最大吸收波长位于５２２ ｎｍ 处,Ｃｄ（Ⅱ） 含量在０～２０μｇ／２５ｍ Ｌ范围内符合比耳定律,表观摩尔吸光系数为２．０５ ×１０５ Ｌ·ｍ ｏｌ－ １·ｃｍ － １。已直接用于废水中微量镉的测定。     

1-(2-苯并噻唑)-3-(4-硝基苯)-三氮烯的合成及其与镉(Ⅱ)的显色反应研究

报道了１－（２－苯并噻唑）－３－（４－硝基苯）－三氮烯（ＢＴＮＰＴ）的合成及与镉（Ⅱ）的显色反应研究。在ＴｒｉｔｏｎＸ－１００的存在下,ｐＨ１１．６时,镉（Ⅱ）与ＢＴＮＰＴ形成摩尔比＝１∶２型黄色络合物,在４３５ｎｍ处有一最大正吸收,在５３０ｎｍ处有最大负吸收。以４３５ｎｍ为参比波长,５３０ｎｍ为测量波长进行双波长测定,表观摩尔吸光系数为２．５２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１,线性范围为０～１０μｇ／２５ｍＬ。已用于测定地面水和人发中的镉含量。     

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.     

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.     

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.     

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%).