桥环二茂钛、锆、铁金属衍生物的研究

本文用β,β'-双环戊二烯基乙醚二钠与TiCl4, ZrCl4, (C5H5)TiCl3和FeCl2在四氢呋喃中反应合成了新型氧桥环戊二烯基钛、锆和铁衍生物。在企图合成硫桥环戊二烯基化合物时, 得到的却是四亚甲基桥联双环戊二烯基金属衍生物。(苯二亚甲基)双环戊二烯基二钠与FeCl2反应合成了对、间(苯二亚甲基)二茂铁。讨论了新化合物的X射线光电子能谱和Mossbauer谱。     

有机镧系络合物[Li(THF)2]2(μ-Cl)4(η^5-C5H5)Ln.THF的合成

Manastyrskyj 等首次报道了重稀土环戊二烯二氯化物 C_5H_5L_nC(?)_2(Ln=Sm～Lu)的合成,但未得到相应的轻稀土环戊二烯基二氯化物。他们把这一结果归因于镧系收缩和配位不     

利用歧化反应的逆反应合成C_5H_5LnCl_2·2LiCl·5THF配合物(Ln=La,Nd)

由于镧系收缩和配位不饱和性,导致长期不能合成轻稀土环戊二烯基氯化物。陈文启等借严格控制氯化稀土与环戊二烯基钠的摩尔比为1:0.5,制备了环戊二烯基轻稀土二氯化物(Pr、Ce、Nd),但即使将这一摩尔比调整为1:0.25也不能得到类似的镧的化合物。李毅等以LnCl_3—LiCl(Ln=La、Nd)的四氢呋喃溶液和等摩尔的C_5H_5Na反应,以比较高的收率制备了[Li(THF)_2]_2(μ-Cl)_4C_5Ln·THF,并测定了其晶体结构。我们     

四甲基乙撑桥联二环戊二烯基环戊二烯基稀土配合物的合成与表征

合成了四个甲基乙撑桥联二环戊二烯基环戊二烯基稀土四氢呋喃配合物,采用元素分析、红外光谱、核磁共板、热失重和质谱等方法对所得到配合物进行表征,并用X光衍射法测得Me_4C_2(C_5H_4)_2SmC_5H_3(THF)的晶体结构。该晶体属正交晶系C_(e2a)空间群,a=1.1696(6),b=1.2539(5),c=2.9432(15)nm;V=4.316(4)nm~3,z=8,D_c=1.54g·cm~(-3)。三个环戊二烯基Sm-C(η~5)距离分别为0.272(3),0.276(3),0.278(3)nm和Sm-O键长为0.253(1)nm。     

配合物[Li(THF)_2]_2(μ—Cl)_4[(η~5—CH_3C_5H_4)Nd·THF]的合成及其晶体结构

环戊二烯基希土氯化物是一类合成希土有机配合物的重要前身。尽管在1980年前没能成功地合成含轻希土元素的这类配合物,但目前已发现,采用具有较大体积的取代环戊二烯做配体,如C_5Me_5H,C_5H_3〔Si(CH_3)_3〕_2H,C_5Me_4C_3H_7H和桥联的配体(C_5H_4)_2(CH_2)_3H_2都可得到相应的取代环戊二烯基轻希土氯化物。控制LnCl_3和CpNa的反应摩尔比也可以成功地得到这类轻希土的环戊二烯基氯化物。     

全甲基硅桥联双环戊二烯的合成

全甲基硅桥联双环戊二烯的合成邝代治（衡阳师范专科学校化学系，４２１００８）环戊二烯及其衍生物与过渡金属配合物的合成是金属有机化学中非常活跃的研究课题。人们在这些研究领域中感兴趣的是用各种基团来修饰环戊二烯配体，近来桥联双环戊二烯的合成已有不少报道￣［...     

环戊二烯掺杂乙烷桥联有序介孔材料的制备、表征及应用

 以单硅酯 (2-(环戊基-1,3-二烯基) 乙基) 三乙氧基硅烷 (TEECp) 和含有亚乙基桥键的硅酯 1,2-二 (三乙氧基硅基) 乙烷为硅源, 以三嵌段共聚物 P123 为模板剂, 通过调节 TEECp 预水解时间, 采用共聚法合成了环戊二烯掺杂乙烷桥联材料 (Cp-PMO), 并采用小角 X 射线衍射、N2 物理吸附、透射电镜、红外光谱和热重等技术对样品进行了表征. 结果表明, 环戊二烯基被成功引入到乙烷桥联材料中, 所得 Cp-PMO 样品具有高度有序的二维六方介孔孔道, 热稳定性较高; 随着材料中环戊二烯含量的增加, 其有序性降低, 孔径、比表面积和孔体积均有所减小, 孔壁逐渐增厚. 在乙酸乙酯与正丁醇的酯交换反应中, Cp-PMO 样品表现出较高的催化活性. 当该样品中环戊二烯含量为 30% 时, 乙酸乙酯转化率和乙酸丁酯收率分别可达 19.3% 和 10.6%.     

二(环戊二烯基)氯化镨和二茚基稀土氯化物的合成

二(环戊二烯基)氯化镨的合成已知的二(环戊二烯基)稀土氯化物(C_5H_5)_2LnCl(Ln=Sm～Lu)均为重稀土化合物.曾有人试图合成二(环戊二烯基)轻稀土(Ln=La～Nd)氯化物但未获成功,认为是由于镧系收缩和轻稀土配位的不饱和性.然而,用取代环戊二烯基和茚基或含螯合物为配位体却可以合成轻稀土的化合物.我们采用 NdCl_3·2THF 和环戊二烯钠在 THF 溶液中室温下反应制得了(C_5H_5)_2NdCl·THF.它具有二聚体的结构,属单斜晶系,空间群为 P2_1/c,该化合物在抽空加热下脱 THF,得到组成符合(C_5H_5)_2NdCl 的残余物.     

三甲硅基环戊二烯基稀土二氯化物的合成

1978年Lappert等人首先合成了二(三甲硅基环戊二烯基)稀土氯化物[Li(THF)](Me_3SiC_5H_4)_2LnCl] (Ln=Y,Yb)和Yb(C_5H_4SiMe_3)_2。三甲硅基环戊二烯基稀土二氯化物,则未见报导.采用三甲硅基环戊二烯作为合成稀土金属有机化合物的配体,不仅可以增加所合成的稀土化合物在非极性溶剂中的溶解度,而且在反应过程中可以减小歧化反应的发生,得到所要求的产物.我们探索了三甲硅基环戊二烯基稀土二氯化物的合成,并对所得到的产物进行了鉴定.     

1,1'-(四甲基二硅撑)双[环戊二烯基三羰基钼配合物]的合成及结构

1,2-二环戊二烯基四甲基二硅烷与正丁基锂作用生成(四甲基二硅撑)双[环戊二烯基负离子盐],后者随即与六羰基钼反应即形成1,1'-(四 甲基二硅撑)双[环戊二烯基三羰基钼负离子盐],分别与四种不同的卤化物反应,生成在钼原子上发生烃基化的产物与冰醋酸作用,随即分别与CCl~4及NBS反应,生成相应的钼氯化物和钼溴化物作用发生氧化偶联反应,生成Mo-Mo键断裂的钼碘化物,以元素分析、IR及^1HNMR表征了2-9的结构.并对5的单晶进行了X射线衍射分析.它的晶体属三斜晶系,PI空间群,晶体学数据:偏差因子R=0.043,R~W=0.055.     

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.     

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.     

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.