稀土元素的色-极谱分析

本文报导了一种测定稀土元素分量的流动极谱检测器。稀土元素混合液经过高速离子交换色谱分离后,将含有DTPA(二乙三胺五乙酸)或DCTA[1,2环己二胺四乙酸(反式)]的检测液以恒定的流速用泵注入色谱柱流出液中,使其混合后流经装有滴汞电极的检测池。当稀土元素在洗脱液中出现时,由于氨羧络合剂(DTPA或DCTA)和稀土元素络合导致氨羧络合剂的阳极扩散电流减小。试验表明,极谱讯号峰高与洗脱液中稀土元素的含量成正比。     

[HgI4]2－-蛋白质离子缔合物体系共振瑞利散射和共振非线性散射光谱及其分析应用

在0.0035～0.0045 mol/L硫酸介质中, 牛血清白蛋白(BSA)、人血清白蛋白(HSA)、卵白蛋白(OVA)和血红蛋白(HGB)等蛋白质以带正电荷的阳离子存在. 它们能借助于静电引力和疏水作用力与配阴离子[HgI4]2－-反应形成结合产物, 此时将引起共振瑞利散射(RRS)、二级散射(SOS)和倍频散射(FDS)显著增强, 并且出现新的散射光谱. 其最大RRS, SOS和FDS波长分别位于390, 760和390 nm附近. 在一定范围内, 三种散射增强(ΔIRRS, ΔISOS和ΔIFDS)与蛋白质浓度成正比, 方法具有高灵敏度, 三种方法对于不同蛋白质的检出限分别在5.7～15.9 ng/mL (RRS), 8.2～15.4 ng/mL (SOS)和11.2～22.1 ng/mL (FDS)之间, 均可用于痕量蛋白质的测定. 本文研究了[HgI4]2－与蛋白质相互作用对RRS, SOS和FDS光谱特征和强度的影响, 考察了适宜的反应条件, 并以RRS为例考察了共存物质的影响, 表明方法有良好的选择性. 据此, 利用[HgI4]2－与蛋白质的相互作用发展了一种用共振光散射技术、灵敏度高、简便、快速测定蛋白质的新方法. 本方法可用于血清和人尿中总蛋白质的测定.     

反相离子对高效液相色谱法测定几种氨羧络合剂

本文提出用反相离子对高效液相色谱法,分离、测定了三组氨羧络合剂NTA-EDTA-HEDTA、EGTA-NTA和EGTA-HEDTA.讨论了pH、有机溶剂和离子对试剂对分离的影响。本法可用于生理盐水、植物营养液和合成洗涤剂中氨羧络合剂的含量测定。     

长链氨羧络合剂萃取稀土饵

研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸钠(Na2R2Y)的氯仿溶液萃取稀土饵的行为;考察了溶液酸度、络合剂浓度、相比和温度对萃取率的影响.用摩尔比法测定了Na2R2Y与Er3+的络合摩尔比为1∶1;结果表明,Na2R2Y的氯仿溶液对饵的萃取率随络合剂浓度的增大而增大,随温度的升高而降低.     

N,N′-二(十二烷基)乙二胺二乙酸萃取镉的研究

镉(Ⅱ)离子是废水中的重要污染成分[1,2].本文研究氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸(H2R2Y)的氯仿溶液对镉的萃取行为;用电导法、摩尔比法证实了H2R2Y与Cd2+的络合比为1∶1;考察了酸度、络合剂浓度、相比及温度对萃取的影响.     

稀土－钴－茜素氨羧络合剂异核络合物极谱吸附波的研究

稀土－钴－茜素氨羧络合剂异核络合物极谱吸附波的研究崔毅,李南强（北京大学化学系,北京,１００８７１）关键词稀土异核络合物,络合吸附波,单扫极谱Ｌｅｏｎａｒｄ［１］曾用光度法初步确定了Ｌａ（Ⅲ）或Ｃｅ（Ⅲ）、Ｎｉ（Ⅱ）或Ｃｏ（Ⅱ）与茜素氨羧络合剂（ＡＬ...     

用硫酸软骨素A作探针共振瑞利散射及共振非线性散射法测定蛋白质

在pH 1.8～2.5的Britton-Robinson (BR)缓冲介质中, 硫酸软骨素A (CSA)的硫酸酯基离解而以带多个负电荷的大阴离子存在, 而人血清白蛋白(HSA)、牛血清白蛋白(BSA)、糜蛋白酶(Chy)、溶菌酶(Lyso)和α-淀粉酶(α-Amy)等蛋白质处于其等电点(pI)之下, 则是带多个正电荷的大阳离子, 两者可借静电引力、氢键作用、疏水作用而结合形成复合物. 此时将引起共振瑞利散射(RRS)和二级散射(SOS)、倍频散射(FDS)等共振非线性散射(RNLS)的显著增强并出现新的散射光谱. 3种散射的散射增强(ΔI_RRS, ΔI_SOS和ΔI_FDS)均在一定范围内与蛋白质的浓度成正比, 方法具有高灵敏度. 三种方法对蛋白质的检出限分别为4.5～12.0 (g/L (RRS法)、8.9～15.8 (g/L (SOS法)和13.4～31.5 (g/L (FDS法), 其中以CSA-BSA体系灵敏度最高(检出限可达4.5 (g/L). 研究了反应体系的RRS, SOS和FDS的光谱特征、适宜的反应条件和影响因素, 讨论了反应机理、结合模式以及散射增强的原因. 并以CSA-BSA体系为例考察了共存物质的影响, 表明方法有良好的选择性. 方法可用于正常人血清及尿样中蛋白质的测定.     

电化学研究茜素络合剂-镨(Ⅲ)二元络合物与蛋白质相互作用

用电化学方法对茜素络合剂-镨(Ⅲ)二元络合物与牛血清白蛋白(BSA)的相互作用进行了研究,发现在pH 4.9的六次甲基四胺[(CH2)6N4]缓冲液中,茜素络合剂-镨(Ⅲ)络合物能与牛血清白蛋白生成一种非电活性的络合物,导致茜素络合剂-镨(Ⅲ)的峰电流降低,峰电流降低值Δip在一定范围内与BSA的浓度呈线性关系,线性范围为1.5~17.5 mg.L-1,相关系数为0.997,检出限为1.5 mg.L-1,RSD为2.1%,回收率为102%,该法可用于蛋白质的测定。     

“一步法”合成新型不对称三甲川吲哚菁荧光染料及荧光标记

首次合成了一种含非离子水溶性基团的水溶性不对称三甲川吲哚菁荧光染料.以N-(3,5-二(2-(2-甲氧乙氧基)乙氧基)乙氧基)苄基-2,3,3-三甲基-5-磺酸基-3H-吲哚、N-对羧苄基-2,3,3-三甲基-5-磺酸基-3H-吲哚和缩合剂N,N′-二苯基二甲脒为原料,采用"一步法"合成,用自制简易C18反相硅胶填料柱分离即可得到纯品,目标染料经HRMS、NMR表征;测试了染料的紫外光谱性能、荧光光谱性能和光稳定性能;研究了染料标记牛血清白蛋白(BSA)和细胞染色.结果表明:在吲哚"N"原子上引入具有PEG链的非离子水溶性基团,使目标染料合成简便,纯化简单,产率达到73%;荧光量子产率(Φ)达到0.3;标记蛋白质标示率(D/P)为1.87;染料对固定细胞和活细胞染色结果有显著差异,能有效区分细胞存活状态.     

胶束溶液中钙黄绿素-荧光桃红间荧光共振能量转移的研究及应用

研究了钙黄绿素-荧光桃红体系的荧光共振能量转移机理及其在蛋白质测定中的应用.实验表明:在聚乙烯醇存在下,于HAc-NaAc缓冲液(pH 5.30)中,钙黄绿素与荧光桃红之间能发生有效的能量转移.根据Frster理论,探讨了钙黄绿素与荧光桃红分子间能量转移机理.结果表明:蛋白质的加入使钙黄绿素-荧光桃红体系发生荧光猝灭...     

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.     

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.     

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.     

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%).     

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.     

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.     

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.