希土异硫氰酸盐与二甲基乙酰胺配合物的热分析研究

本文利用TG-DTA-DTG技术对除了钪、钷以外的十五种希土异硫氰酸盐与二甲基乙酰胺的固体配合物进行了热分析研究。测定了它们的熔点和熔化热,分别用Doyle法和Kissinger法计算出各配合物热分解过程氧化反应的活化能,两种方法所得结果基本一致。实验发现镧系元素的该系列配合物的熔化热和热分解反应的活化能均随配合物中心离子—镧系元素原子序数的递增而呈现“双峰现象”。     

气相色谱法研究金属草酸配合物的热分解

用气相色谱(GC)、热重(TG)和差示扫描量热(DSC)法研究金属草酸配合物的热分解已有报道。本文用GC法研究两种合成的草酸配合物[三水合三草酸合铁(Ⅲ)酸钾和三水合三草酸合钴(Ⅲ)酸钾]的热分解反应,配合TG,DSC测试数据,探讨了分解机理,并用微机编程序计算获得反应级数和活化能。     

稀土氨基酸配合物RE(Val)Cl3•6H2O(RE = Nd，Sm)的热分解动力学

合成了稀土氨基酸配合物晶体——三氯化缬氨酸六水合钕、钐，对合成样品进行了EDTA滴定、元素分析、红外光谱分析、热重、差热分析以及熔点测定，推测了配合物的热分解机理，采用Achar法和Coats-Redfern法研究了配合物热分解的非等温动力学过程，给出了各配合物样品失水阶段第一步反应和氨基酸骨架断裂阶段第一步反应的活化能（E）、指前因子的对数值（ln(A)）及热分解反应动力学方程式.     

铽芳香族羧酸配合物的热分解机理及动力学研究

本文采用TG-DTA-DTG等技术研究了铽羧酸配合物的热分解过程,通过对中间产物进行红外光谱、元素分析、确定了热分解机理。采用三种方法尝试求得了希土羧酸配合物热分解过程的活化能和焓变,发现并总结了其相变过程。     

稀土异硫氰酸盐与二甲基亚砜配合物的合成,性质及热分析研究

合成了15种稀土异硫氰酸盐与二甲基亚砜(DMSO)的配合物,经化学分析和元素分析确定其组成为RE(NCS)_s·mDMSO(RE=La,Ce,Pr,Nd,Sm,Eu,Gd;m=5.RE=Tb,Dy,Ho,Er,Tm,Yb,Lu,Y;m=4).用红外光谱及X射线衍射技术进行了表征.运用TG-DTA-DTG联用技术研究了该系列配合物的热分解过程,求算热重动力学参数发现,第一步热分解阶段的活化能随着中心高子——镧系元素原子序数的依次递增呈现“双峰现象”.     

β-二酮镧系元素络合物热行为的研究

本文用差热分析(DTA)、热重法(TG)、微商热重法(DTG)研究了十二种三价镧系金属离子与1,1,1,2,2,3,3七氟-7,7,二甲基-4,6辛二酮的络合物Ln(fod)_3·mH_2O的脱水过程和热分解过程的动力学。其脱水反应发生在100℃附近。络合物最大热分解速率的温度和热分解反应活化能均随中心金属原子——镧系元素原子序变化,呈现“双峰”现象。     

含能配位聚合物[Cu(tza)2]n的晶体结构、热分析、感度和催化性能

以碱式碳酸铜和四氮唑乙酸在水中反应制备得到四唑乙酸铜(II)含能配位聚合物, 并培养出单晶. 运用元素分析, FT-IR分析和X-射线单晶衍射对标题配合物的组成和结构进行了全面的表征. 采用差示扫描量热分析(DSC)和热重-微分热重分析(TG-DTG)研究了标题配合物的热分解过程, 表明标题配合物的热分解主要包含三个放热峰. 用Kissinger和Ozawa-Doyle法对标题配合物的第一放热分解过程进行了动力学研究, 计算得到其活化能为356.1 kJ/mol. 对配合物的撞击、摩擦、火焰感度和5s爆发点测试表明该配合物具有一定的感度, 有望作为含能材料应用于相关领域. 同时研究了标题配合物对RDX热分解的影响, 结果表明: 标题配合物可以使RDX的放热分解峰的温度提前16.4 ℃,分解速度加快, 对RDX具有良好的催化作用.     

用非等温DSC曲线确定Ln(NCS)_3·4C_6H_5CH_2NH_2的热分解反应机理函数及热分解反应动力学参数

本文利用非等温DSC曲线对十二种镧系元素异硫氰酸盐与苄胺形成的配合物Ln(NCS)_2.4C_6H_5CH_2NH_2(Ln=La、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb)进行了非等温动力学研究,并运用积分法和微分法进行了分析,推断了它们的热分解反应机理函数,当Ln=La、Pr、Nd、Sm、Eu、Gd时,配合物的热分解动力学方程式da/dt=A·e~(-E/RT·3)(1-α)~(2/3);当Ln=Tb、Dy、Ho、Er、Tm、Yb时,则为dα/dt=A·e~(-E/RT·)(1-α),呈现“钆断”现象.此外还得到了该系列配合物的热分解反应动力学补偿效应表达式.     

双硫脲金(Ⅰ)配合物(Cl-)的红外光谱及热分解机理的研究

测定了双硫脲金(Ⅰ)配合物(Cl^-)的红外光谱、差热曲线(DTA)、热重曲线(TG);测定在21个不同温度下配合物发生分解反应后产物的红外谱图;提出了配合物热分解机理的一些论断;估算了热分解反应的活化能和指前因子;查明了双硫脲金(Ⅰ)配合物在升温速度为10℃/min条件下在230-260℃温度范围内配位体中硫脲能发生同分异构转变,硫脲转变为异硫氰酸铵;分解反应从～240℃开始,～322℃结束,650℃以上Au₂S分解为金属金。     

固相配位化学反应研究 ⅩⅩⅣ.一取代基五氰合铁(Ⅱ)类配合物热分解的质谱研究

以四极质谱法为主要手段研究了一取代基五氰合铁(Ⅱ)类配合物在真空中的热分解,结合穆斯堡尔谱结果研究了固相物的化学组成,阐明了配合物的热分解机制,并发现配合物的热稳定性顺序与取代基团的光谱化学序列一致.对该类配合物的热分解动力学研究表明,分解活化能与分解峰值温度之间存在线性关系.     

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.