昆明西山菊科植物—土壤系统Fe,Mn,Ni分布特征研究

利用统计分析和吸收系数描述了昆明西山菊科植物－土壤系统中Ｆｅ、Ｍｎ、Ｎｉ分布特征。结果表明，除凤毛菊外菊科植物－土壤系统中植物对Ｎｉ元素均表现出相对的稀释和缓冲作用。     

无机含氧酸中央体价轨道杂化方案的讨论

无机含氧酸中央体价轨道杂化方案的讨论李炳焕（唐山师范专科学校化学系０６３０００）常见无机含氧酸根离子的构型有正四面体和平面三角形，分别以ＭＯｎ－４和ＭＯｎ－３表示。其中央体Ｍｎ＋与配体Ｏ２－之间可以σ键和π键结合，在成键过程中，中央体价轨道的杂化方案...     

双核金属酞菁类化合物催化脱硫机理研究Ⅲ──M（Ⅱ）Pc－PcM（Ⅱ）的电子结构及M（Ⅱ）与Pc间的键合方式

采用ＩＮＤＯ／Ｓ方法研究了双核金属酞菁类化合物Ｍ（Ⅱ）Ｐｃ－ＰｃＭ（Ⅱ）（Ｍ＝Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ）的电子结构．结果表明当金属离子Ｍ（Ⅱ）与酞菁环键合后，其价电子重新布居，从而导致在Ｍ＝Ｃｒ、Ｍｎ、Ｆｅ、Ｚｎ时中心金属离子从酞菁环得到电子；而当Ｍ＝Ｃｏ、Ｎｉ、Ｃｕ时却是中心金属离子向酞菁环转移电子．键合方式的研究结果表明在Ｍ（Ⅱ）Ｐｃ－ＰｃＭ（Ⅱ）分子中，中心金属离子与酞菁环间存在着σ配键、反馈π键和离域π键三种化学键形成，从而在中心金属离子与酞菁环间产生灵活的“电荷呼吸”作用，构成了双核金属酞菁类化合物氧化还原作用的基础．     

导电高聚物聚2，5－二甲基苯胺的化学合成与特性

报道了聚２，５－二甲基苯胺（ＰＤＭｅＡｎ）的化学合成，并用标准四探针方法测定其电导率，以ＦＴＩＲ、ＵＶ－Ｖｉｓ吸收光谱、元素分析和ＣＶ法对其性质进行了研究，ＰＤＭｅＡｎ的结构与聚苯胺和聚２，５－二甲氧基苯胺的结构类似，是由其单元通过氮原子（Ｎ）在对位上键合而成，本征态的ＰＤＭｅＡｎ能溶于多种有机溶剂，如ＣＨ２Ｃｌ２、ＣＨＣｌ３、ＤＭＳＯ、ＤＭＦ等。     

过渡金属四—（对—硝基）苯基卟啉配合物的XPS研究

用ＸＰＳ研究了四－（对－硝基）苯基卟啉及其Ｍｎ、Ｃｏ、Ｎｉ、Ｃｕ配合物和卟啉周边带有不同取代基的６种锰卟啉配合物。π→π跃迁能、ＮＩＳ及金属Ｍ２ｐ３／２结合能的位移证明，这些金属配合物是金属镶嵌在大π键体系共轭环中形成的金属卟啉配合物，不同锰卟啉中Ｍｎ２ｐ３／２结合能随卟啉取代基团电负性的降低而下降，不同锰卟啉的ＸＰＳ数据可用于推断配合物中取代基的结构。     

稀土对SiMnCr和SiMnMo结构钢回火脆性的影响

研究了ＳｉＭｎＣｒ钢和ＳｉＭｎＭｏ钢低温回火过程中机械性能的变化。稀土对低温回火时的材料强度没有明显的影响。ＳｉＭｎＣｒ钢和ＳｉＭｎＭｏ钢分别在３５０和４００℃存在ＴＭＥ谷底值；稀土对谷底值的温度虽然没有影响，却可以在一定程度上改善其数值。稀土改善回火脆性是细化晶粒和抑制奥氏体晶界脆化作用的结果。     

水溶性金属卟啉肿瘤靶向磁共振成像造影剂的研究

利用显微荧光－阿达玛变换三维图像分析研究了Ｃｕ－ＴＳＰＰ，Ｍｎ－ＴＳＰＰ，Ｃｕ－ＴＭＡＰ，Ｍｎ－ＴＭＡＰ４种水溶性金属卟啉人细胞间质进入肿瘤细胞内的富集过程，对金属卟啉的自旋－晶格驰豫性能（Ｒ１）的天空结果表明，Ｍｎ（Ⅱ）卟啉配合物的Ｒ１、值结Ｇｄ－ＤＴＰＡ提高１．５－２倍。     

酞菁锰络合物的电化学与光谱电化学研究

采用微电极电化学与薄层光谱电化学方法,研究了４－特丁基锰酞菁（ＴｂＰｃＭｎ）在非水溶剂中的电化学行为。结果表明,在二氯乙烷和四氢呋喃溶剂中,得到的氧化和还原过程分别对应于Ｍｎ（Ⅲ）／Ｐｃ－环阳离子自由基,Ｍｎ（Ⅲ）／Ｍｎ（Ⅱ）、Ｍｎ（Ⅱ）、Ｍｎ（Ⅱ）／Ｍｎ（Ⅰ）以及Ｍｎ（Ⅰ）／Ｐｅ环阴离子自由基的生成步骤。轴向配位效应考察表明,阴离子与锰金属中心的键合能力的顺序为：Ｃｌ＾１〉Ｉ＾－１〉ＣｌＯ４＾－     

Mo(W)-Cu(Ag)-S原子簇化合物的研究现状

本文在研究Ｍｏ（Ｗ）－Ｃｕ（Ａｇ）－Ｓ原子簇化合物的低热固态合成化学基础上，详细地对该类簇合物进行了归纳，从中提出；１，ＭＯ４－ｎＳｎ＾２＾－（Ｍ＝Ｍｏ，Ｗ；ｎ＝２，３，４）作为配体中心。２，氧原子在簇合物中仅作为端基，不参与同其他金属成键。３，单个ＭＳ４（Ｍ＝Ｍｏ，Ｗ）基团最多只能键合六个Ｃｕ（Ａｇ）原子，即最大核数为七。４，迄今为止所有Ｍｏ（Ｗ）－Ｃｕ－Ｓ原子簇化合物中Ｃｕ均为＋１价。５，预计     

簇离子Mo_3S_4M~（n＋）中M与Mo成键作用及电子光谱（M＝Fe、Ni，n＝4；M＝Cu，n＝5）

应用ＩＮＤＯ／Ｓ半经验量子化学方法，对簇合物离子Ｍｏ３Ｓ和Ｍｏ３Ｓ４Ｍｎ＋（Ｍ＝Ｆｅ、Ｎｉ，ｎ＝４；Ｍ＝Ｃｕ，ｎ＝５）分别进行分子轨道计算。根据计算得到的簇离子中的原子表观电荷和成键指标，说明Ｆｅ、Ｎｉ、Ｃｕ＋与Ｍｏ３Ｓ成键作用的相对强度依次是Ｆｅ－Ｍｏ＞Ｎｉ－Ｍｏ＞Ｃｕ＋－Ｍｏ。比较了用含组态作用的ＩＮＤＯ／Ｓ方法计算得到的电子跃迁能与实验得到的电子吸收光谱值，并讨论了吸收峰归属情况。对于Ｍ为Ｆｅ、Ｎｉ的簇离子Ｍｏ３Ｓ４Ｍ４＋，最低能量的电子跃迁吸收峰起源于异金属间电荷转移跃迁（ＭＭ’ＣＴ）；而Ｍｏ３Ｓ４Ｃｕ（５＋）簇离子观察到的吸收峰主要是Ｍｏ３Ｓ芯的局域内电荷转移跃迁。根据理论计算结果，由Ｃｕ＋离子到Ｍｏ３Ｓ的电荷转移跃迁谱线，大约在４６０００ｃｍ－１以上才能观察到吸收峰。从Ｍｏ３Ｓ４Ｆｅ４＋次低能量吸收峰的实验值１６６００ｃｍ－１和理论值１６５００ｃｍ－１与Ｍｏ３Ｓ的最低能量吸收峰的实验值１６６００ｃｍ－１和理论值１６９００ｃｍ－１比较，表明无论从理论上或实验上都能证实簇离子Ｍｏ３Ｓ４Ｆｅ４＋在能量为１６６００ｃｍ－１处的吸收峰是起因于Ｍｏ３Ｓ芯的局域内电荷转移跃迁。     

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.     

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.     

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.     

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.     

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.