多元校正—紫外—可见分光光度法同时测定铬（Ⅵ）和铬（Ⅲ）

本文研究在ＰＨ３．０－０．７０－８０℃加热条件下，Ｃｒ（Ⅲ）与ＥＤＴＡ形成紫色络合物，其最大吸收波长为５３７．５ｎｍ，而在此条件下，Ｃｒ（Ⅵ）几乎不与ＥＤＴＡ反应，利用Ｃｒ（Ⅲ）络合物和Ｃｒ（Ⅵ）离子本身吸收光谱间的差异，借助于最小二乘法解析两物种吸收光谱的重叠问题，进而建立了多波长同时光度测定Ｃdisplay status     

铬(Ⅵ)-对二甲氨基苯基荧光酮-β-环糊精-酒石酸钠荧光熄灭反应及其应用

在HCl介质中，溶液中的铬(VI)与对二甲氨基苯基荧光酮(p-DMPF)，β-环糊精(β-CD)和酒石酸钠(Tart)反应产生多元混合络合物，使对二甲氨基苯基荧光酮溶液的荧光明显熄灭，据此建立了测定痕量铬的荧光熄灭新方法。该体系的最大激发波长λex=365nm，最大发射波长λem=527nm，铬(Ⅳ)含量在0～2．0μg／25ml范围内，荧光熄灭程度与铬(Ⅳ)浓度成正比，此方法简单，灵敏度高，可用于水样中铬(Ⅳ)含量的测定，结果满意。     

二溴对甲基偶氮磺褪色光度法测定铝合金中微量铬

在硝酸介质中,铬(Ⅵ)与二溴对甲基偶氮磺生成1:3物质的量比的稳定络合物,导致显色剂二溴对甲基偶氮磺吸光度降低,据此建立了褪色光度法测定铝合金中铬(Ⅵ)含量.对反应介质的种类和酸度、显色剂的用量、反应时间、共存离子的干扰等影响因素进行了试验并予以优化.在530 nm波长测定时,铬(Ⅵ)的质量浓度在0.032～0.48 mg·L-1范围内,反应体系吸光度的降低值△A与44(Ⅵ)浓度呈线性关系,表观摩尔吸光率为4.34×104L·mol-1.·cm-1.用于直接测定铝合金中微量铬的含量,测定值与标准值相符.相对标准偏差(n=8)小于2%.     

双核钛氢络合物在二苯乙炔加氢反应中的催化作用

我们曾研究了Cp_2~′TiCl_2-Pr~iMgBr体系存在下,二苯乙炔的催化加氢反应,为了探讨催化剂结构对反应的影响,本文考察了几种双核钛络合物的催化活性,发现它们能对炔烃的加氢起催化作用,随络合物分子中2个钛原子的靠近,其加氢催化活性明显减小。     

2，6－二氨基吡啶与苦基氯的反应历程研究

对２，６－二氨基吡啶与苦基氯的反应历程进行了研究。通过二氨基吡啶与几种多硝基卤代苯的反应、溶剂效应、ＮａＦ的促进作用和紫外光谱吸收，证实该反应属于芳香族亲核取代反应类型，按加成－消除历程进行，反应过渡态涉及一个Ｍｃｉｓｅｎｈｅｉｍｅｒ络合物。     

乙二醇二缩水甘油醚的合成及作为阳离子型紫外光固化稀释剂性能研究

以三氟化硼乙醚络合物为催化剂,以氢氧化钠为成环反应的闭环剂,利用乙二醇和环氧氯丙烷为原料合成了乙二醇二缩水甘油醚.研究了催化剂三氟化硼乙醚络合物用量、环氧氯丙烷和乙二醇摩尔比、氢氧化钠和乙二醇摩尔比,以及成环反应温度这些因素对合成反应的影响.结果表明较好的合成反应条件是:三氟化硼乙醚络合物质量分数为0.40%,环氧氯丙烷和乙二醇较佳摩尔比为2.4:1,氢氧化钠和乙二醇较佳摩尔比为2.2:1,较佳的成环反应温度为30℃.同时,把乙二醇二缩水甘油醚作为稀释剂加入到环氧树脂E-51中,利用三芳基锍鎓六氟锑酸盐作为引发剂,制备了阳离子型紫外光固化涂料,其紫外光固化膜的拉伸强度为46.25MPa,杨氏模量为1487.26MPa,断裂伸长率为6.27%.     

含二苯联恶二唑大环多胺及其配合物的合成

用2,5-双-(间甲酰基苯基)-1,3,4-恶二唑和相应的二胺，经[2+2]缩合环化反应，合成了三个含二苯联恶二唑的新型大环多胺4、5和7以及5的钡络合物。     

络合物(μ-RS)(μ-R′S)Fe_2(CO)_6的三苯基膦或三苯基胂取代衍生物的合成及结构

关于对称型双烃硫六羰基二铁的膦、肿取代物的合成及结构已有文献报道,然而关于非对称型双烃硫六羰基二铁迄今只报道过它们的三苯基膦衍生物,而且R和R′皆为一般烃基。我们通过Michael反应,用加成-醇解等方法合成了一些含氰基、酯基或酮羰基的双烃硫六羰基二铁络合物,这为进一步研究在硫桥烃基中含官能团的这类络合物的取代反应     

2-(2-喹啉偶氮)-5-二乙氨基苯甲酸固相萃取光度法测定环境水样中的镍

用2－（2－喹啉偶氮）－5－二乙氨基苯甲酸（QADEAB）与镍的显色反应及Waters Porapak^R Sep-Park固术萃取小柱对显色络合物的固相萃取，建立了测定水样中μg/L级镍的新方法。水样中的镍在pH=8.0的硼酸－磷酸二氢钾缓冲介质中和Tween 80存在下与QADEAB反应生成2：1稳定有色络合物，该络合物可用Waters Porapak^R Sep-Park固相萃取小柱富集，用乙醇洗脱后用光度法测定，可测定水样中μg/L级的镍。方法用于几种环境水样分析，结果令人满意。     

手性酒石酸二酰胺配体的合成及其锡络合物与苯甲醛的不对称加成

通过酒石酸乙酯和不同胺的酰胺化, 相应地合成到(+)N,N'-二苯基酒石酸二酰胺(2), (+)N,N'-二苄基酒石酸二酰胺(3),(+)N,N'-二环己基酒石酸二酰胺(4)和(+)N,N'-二正辛基酒石酸二酰胺(5).氯化亚锡与2当量的酒石酸二酰胺反应, 再加入烯丙基溴可制得手性锡络合物6, 锡络合物与苯甲醛反应,得到光学活性的高烯丙基化合物, 产率42～64％ , e.e.值24～62％.     

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%.     

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.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.