Thermodynamic characteristics of the adsorption of 1,3,4-oxadiazoles and 1,2,4,5-tetrazines from methanol and water–methanol solutions onto hypercrosslinked polystyrene

Russian Journal of Physical Chemistry A - The thermodynamic characteristics of the adsorption of several 1,3,4-oxadiazoles and 1,2,4,5- tetrazines from methanol and water-methanol solutions onto...     

1,2,4,5-苯四甲酸铒配合物的合成及其晶体结构

合成了NH4^+[ErC6H2(COO)4.3H2O]^-.4H2O晶体,并测定了其晶体结构,发现稀土Er^+^3跟苯四甲酸中的五个氧原子及三个水的氧原子配位,形成八配位的配合物.配位多面体呈二帽畸变三角反棱柱.晶体结构沿着(001)面呈现一个网状结构.这种结构对研究稀土元素的结构化学、配位化学,化学键理论等提供了有用的实验数据.     

1,2,4,5-苯四酚-四乙酸比浊法测定烟草中的钾含量

1　引　　言钾是烟草中最重要的元素之一 ,其含量对烟草质量有重要影响 ,因而烟草中钾含量的测定具有重要意义。烟草中钾含量的测定常用四苯硼钠重量法或火焰光度法 ,利用比浊法测钾也有报道。 1 ,2 ,4,5 苯四酚 四乙酸的合成和用作钾离子沉淀剂已见报道 ,该试剂对钾具有较好的选择性 ,但用于钾的定量分析还未见报道过。我们发现在聚乙烯醇介质中 ,钾离子和 1 ,2 ,4,5 苯四酚 四乙酸形成稳定的胶体沉淀 ,基于此建立了一种在聚乙烯醇介质中光度比浊测定钾的方法 ,方法快速、简便、准确 ,为快速测定烟草及其制品中的钾含量奠定了基础。2　实…     

Alkylation of Sulfur Ligand in Cysteinate－Iron Chelates by a 1,2,4,5－Tetraoxane

Reaction of a 1,2, 4, 5-tetraoxane with cysteinate-iron in the presence of excess methyl cysteinate led to formation of sulfuralkylated methyl cysteinate in 33 % yield, illustrating a possible mechanism for tetraoxanes‘ antimalarial action.     

1,2,4,5-四嗪含氮取代基衍生物结构和性质的理论研究

在B3LYP/aug-cc-pvDZ理论水平上研究了CN,NO2,NH2,N3,N2H,NHNH2,N4H和N4H3含氮取代基取代1,2,4,5-四嗪环上的两个氢原子生成的衍乍物,预测了它们的分f构犁、分解能及含能性质.对衍生物分解能的研究结果表明.CN取代的衍生物的分解能比未取代时更高,而其余基团的取代使分解能降低.生成热的研究显示取代基化合物的生成热越大,取代1,2,4,5-四嗪中的氢原子后生成衍生物的牛成热也越大;CN,N3和N4H取代的1,2,4,5-四嗪衍生物的单位原子生成热在83.1～95.2 kJ,比文献报道的三叠氮基-均三嗪的(70.2 kJ)更高;N4H,N3,N4H3,N2H和CN取代的1,2,4,5-四嗪衍生物,生成热在904.9～1496.6 kJ·mol-1,但N4H和N4H3取代的衍生物分解能较小,稳定性较差.     

提高光还原水反应产H2效率的研究——添加物1,2,4,5-四甲基-3,6-二吡啶基-六氢-1,2,4,5-四嗪的研究

本实验总结了文献中提高电荷转移反应效率的理论分析和经验,结合光还原水特点,提出了使用具特殊结构的有机化合物及金属有机络合物添加剂提高产H₂效率的广泛可能性。所用添加物若能起到下列作用之一,即可望增进催化体系活性,提高产H₂反应效率。     

3,6-二肼基-1,2,4,5-四嗪的晶体结构及理论研究

通过缓慢蒸发溶剂法培养得到3, 6-二肼基-1, 2, 4, 5-四嗪(DHT)的单晶, 用X-射线单晶衍射仪进行了结构测定. 该晶体属于单斜晶系, P2(1)/c空间群, a=4.032 (4) ?, b=5.649 (6) ?, c=12.074 (14) ?. β=99.32°, Z=2, V=271.4(5) ?3. DHT分子中肼基N原子与四嗪环基本位于同一平面呈现轴对称结构, 分子中的大量氢键使之形成箭尾形排列的三维网络结构. 通过实验测得DHT的燃烧热为1787kJ?mol-1, 5s爆发点为454 K. 在DFT-B3LYP/6-311G*水平下对DHT的电子结构和自然键轨道进行了分析. 通过原子化能的方法计算得到DHT的标准生成热为1075 kJ?mol-1, 与实验值接近. 爆轰性能计算表明, DHT在密度为1.64 g?cm-3时, 爆速和爆压分别为9.27 km?s-1和36.02 GPa, 高于TNT和HMX.     

3,6-二叠氮基-1,2,4,5-四嗪的合成及理论研究

以3,6-双(3,5-二甲基吡唑基)-1,2,4,5-四嗪为原料, 经过肼解反应和重氮化反应, 制得了3,6-二叠氮基-1,2,4,5-四嗪(DAT). 在DFT-B3LYP/6-31G*水平下求得了DAT的分子几何、IR光谱和热力学性质. 计算模拟IR光谱和实测IR光谱的对比表明DAT在固态下不发生叠氮-四唑互变异构反应. 根据IR光谱计算了DAT的热容、焓、熵等热力学参数, 也给出了这些参数和温度T之间的函数关系. 在不破坏四嗪环和叠氮基的原则下通过构建等键反应求得了DAT的精确生成热为1088 kJ•mol^—1. 爆轰性能计算表明DAT爆速D＝8.45 km•s^－1, 爆压P＝31.3 GPa, 高于TNT和HMX.     

Über die Synthese und die Eigenschaften von 1,2,4,5-Tetrazinen, 2. Mitt.

Zusammenfassung Die Behandlung von Thiazol-2- und 6-Acetamino-pyridin-3-nitril mit Hydrazinhydrat führt zu den entsprechenden 3,6-disubstituierten 1,2-Dihydro-1,2,4,5-tetrazinen. Versuche, unter den gleichen Bedingungen die Synthese des 1,2-Dihydrotetrazins aus p-Methoxy-benzylcyanid zu verwirklichen, lieferten ausschließlich das 3,5-disubstituierte 4-Amino-1,2,4-triazol.1. Mitt.:F. Dallacker, Mh. Chem.91, 294 (1960).     

Thermal transformations of 7-aryl-1,6-diazabicyclo[4.10]heptanes and 6,13-diarylperhydrodipyridazino-[1,2-<Emphasis Type="Italic">a</Emphasis>: 1′,2′-<Emphasis Type="Italic">d</Emphasis>]-1,2,4,5-tetrazines

The thermolysis of 7-aryl-1,6-diazabicyclo[4.1.0]heptanes in the absence of 1,3-dipolarophiles leads to dimers of the initially formed azomethineimines, namely, 6,13-diaryloctahydrodipyridazino[1,2-a:1′,2′ Dedicated to the memory of A. A. Potekhin. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1062–1070, July, 2008.     

3,6-二氨基-1,2,4,5-四嗪二聚体分子间相互作用的理论研究

在DFT-B3LYP/6-31G(d)水平下,求得3,6-二氨基-1,2,4,5-四嗪二聚体势能面上3种优化几何构型和电子结构。经基组叠加误差(BSSE)和零点能(ZPE)校正,求得分子间最大相互作用能为-38.88kJ/mol。电荷分布与转移分析表明,二子体系间的电荷转移很少,但接触点上氮原子和氢原子电荷变化比较大。由自然键轨道(NBO)分析揭示了分子间相互作用的本质。对优化构型进行振动分析,并基于统计热力学求得200.0~800.0 K温度范围从单体形成二聚体的热力学性质变化,发现二聚主要由强氢键所贡献,二聚过程在较低温度或常温下能自发进行。     

Synthesis and Crystal Structure of a Novel Cobalt（Ⅱ） Coordination Polymer with 1,2,4,5-Benzenetetracarboxylate

A novel cobalt（II） coordination polymer,[Co（BTEC）1/2]n 1,has been synthesized with Co（NO3）2·6H2O and 1,2,4,5-benzenetetracarboxylic acid （H4BTEC） by the hydrothermal method,and characterized by elemental analysis,IR and single-crystal X-ray diffraction. Crystallographic data for 1： C5HO4Co,Mr = 183.99,monoclinic,space group C2/c,a = 16.619（6）,b = 7.416（3）,c = 8.040（3）A,β = 90.612（4）°,V = 990.8（6） A^3,Z = 8,Dc = 2.467 g/cm^3,μ = 3.390 mm^-1,F（000） = 720,R = 0.0307 and wR = 0.0847 for 912 observed reflections （I 〉 2σ（I））. X-ray crystal structural analysis revealed that each Co（II） adopts a tetrahedral coordination mode to link four separate BTEC ligands via uniform monodentate carboxylate groups and each BTEC ligand possesses an 8-connected geometry to connect eight Co（II） ions. Complex 1 exhibits a rare （4,8）-connected net with （45.6）2（410.614.84） topology.     

高能量密度材料3,3′-偶氮-1,2,4,5-四嗪衍生物的分子设计

运用密度泛函理论(DFT)方法,计算系列3,3′-偶氮-1,2,4,5-四嗪衍生物的生成热.结果显示:—N3取代基在增加3,3′-偶氮-1,2,4,5-四嗪衍生物的生成热方面起了非常重要的作用.通过分析标题化合物的最弱键离解能发现:—NH2或—N3取代基非常有利于增加衍生物的热稳定性.计算的爆速(D)和爆压(p)数值表明:—NO2或—NF2取代基有利于提高3,3′-偶氮-1,2,4,5-四嗪衍生物的爆轰性能.综合爆轰性能和热稳定性的计算结果,3种3,3′-偶氮-1,2,4,5-四嗪衍生物可以作为潜在的品优高能量密度材料(HEDM)候选物.     

Synthesis and structures of methyl-substituted 1,2,4,5-tetrahydro-3H-spiro(benz-2-azepine-3,4′-piperidines)

Methyl-substituted 1,2,4,5-tetrahydro-3H-spiro(benz-2-azepine-3,4-piperidines) were obtained by the intramolecular cyclization of 4-allyl-4-N-benzyl(-phenylethyl)aminopiperidines in an acidic medium. The individual isomers of 1-benzyl-2,5,5-trimethyl-1,2,4,5-tetrahydro-3H-spiro(benz-2-azepine-3,4-piperidine) were isolated, and their structures were established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1528–1532, November, 1991.     

Synthesis and Crystal Structure of a New Zn(Ⅱ) Coordination Polymer Constructed by 1,2,4,5-Benzenetetracarboxylate

A new Zn(Ⅱ) coordination polymer [Zn3(btec)(OH)2(H2O)2]n (1, btec = 1,2,4,5- benzenetetracarboxylate) has been synthesized by hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in mono- clinic, space group C2/c, with a = 19.580(3), b = 5.0137(8), c = 15.975(3), β = 121.629(2)°, V = 1335.3(4)3, C10H8O12Zn3, Mr = 516.27, Z = 4, Dc = 2.568g/cm3, μ = 5.419 mm-1, F(000) = 1016, R = 0.0590 and Rw = 0.1279 for 1110 observed reflections (I > 2σ(I)). X-ray analysis shows that the asymmetric unit of the title compound contains two crystallographically unique Zn(Ⅱ) atoms which are connected through the bridging carboxylate oxygen atoms of the btec ligands and μ2-bridging oxygen atoms of water molecules to generate an infinite one-dimensional chain. The adjacent chains are linked together through the benzene rings of the btec ligands to form a two-dimensional polymeric network. The adjacent two-dimensional layers are further connected together by the benzene rings of btec ligands to give the final three-dimensional structure. The benzene rings act as pillars between two layers.     

树枝形分子1,2,4,5-四芳基苯的合成、荧光性质和电存储效应

采用钯催化条件下多位点Heck偶联反应,以芳香八碘代物1,2,4,5-四{4-[N,N-二(4-碘苯基)氨基]苯乙烯基}苯(TPAB-I)和4-(N,N-二苯基)氨基苯乙烯为反应物,合成了一种新型荧光树枝分子1,2,4,5-四{4-{N,N-二{4-[4-(N,N-二苯基氨基)苯乙烯基]苯基}氨基}苯乙烯基}苯(TPAB-TPA).目标化合物的结构经过红外光谱、核磁共振谱、高分辨质谱确认.树枝分子TPAB-TPA在甲苯、乙酸乙酯、四氢呋喃、二氯甲烷和N,N-二甲基甲酰胺(DMF)溶液中的最大荧光发射峰分别位于483,457,497,531,505 nm.量子产率分别为0.48,0.28,0.23,0.49,0.18,在二氯甲烷和四氢呋喃(THF)中的荧光寿命分别为1.48和1.53 ns.用循环伏安法测定TPAB-TPA的HOMO能级和LUMO能级分别为-5.16和-2.64 eV.制备了ITO/TPAB-TPA/Al三明治型电存储器件,ON/OFF电流比大于104,在1 V的读取电压下,持续时间达到1000 s.     

Molecular structure and electron density distribution in the crystals of 3,6-dimethoxy-1,2,4,5-tetrazine and 3-phenyl-1,2,4,5-tetrazine based on X-ray diffraction data at 120 and 150 K. “Bent” bonds in the six-membered heterocycle

Characteristic features of the molecular geometry and electron density distribution in the crystals of 3,6-dimethoxy-1,2,4,5-tetrazine and 3-phenyl-1,2,4,5-tetrazine have been studied by X-ray structural analysis and quantum-chemical (RHF and MP2) and molecular mechanics (MM3) calculations. An unusual shift of the maxima of the deformation electron density from the N-N bonds toward the center of the heterocycles was found, which may be interpreted as a bending of the corresponding bonds. This bending was confirmed by calculations of characteristics of the electron density distribution within the multipole model.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2443–2450, December, 1995.The work was supported by the International Science Foundation (Grant No. M1F 000) and the Russian Foundation for Basic Research (Project No. 94-03-08338). We thank Dr. P. Mallinson (Chemistry Department, University of Glasgow, Scotland) for help in performance of multipole calculations.     

The experimental and calculational thermochemistry of 1,2,4,5-benzenetetracarboxylic dianhydride: is this 10 pi multiring species aromatic?

The standard (p degrees = 0.1 MPa) molar enthalpy of formation of 1,2,4,5-benzenetetracarboxylic dianhydride in the gaseous phase, -826.8 +/- 3.1 kJ mol-1, was derived from the standard molar enthalpy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry and the standard molar enthalpy of sublimation, at T = 298.15 K, measured by Calvet microcalorimetry. In addition, density functional theory calculations have been performed with the B3LYP, MPW1B95, and B3PW91 density functionals and the cc-pVTZ basis set for 1,2,4,5-benzenetetracarboxylic dianhydride and 1,2,4,5-benzenetetracarboxylic diimide. Nucleus-independent chemical shifts calculations show that the aromaticity is restricted to the benzenic ring in both compounds even though they are formally 10 pi polynuclear species.