3,6-双(1H-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪的合成、表征及量子化学研究

以三氨基胍硝酸盐、戊二酮为起始原料, 经缩合、氧化、取代等反应合成了3,6-双(1H-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪(BTATz), 并通过元素分析、红外、核磁、差示扫描量热法(DSC)等分析手段对其进行了表征. 采用亚硝酸钠/乙酸代替了二氧化氮/N-甲基吡咯烷酮, 改进了氧化步骤, 降低了成本, 简化了合成工艺. 用B3LYP方法, 在6-31G(d,p)基组水平上对其性能进行了计算, 得到了其稳定的几何构型和键级; 在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质, 并得到了温度对热力学性能影响的关系式; 探讨了其热解机理, 推断出四唑环开环时的过渡态和活化能.     

3,3’-偶氮双(6-氨基-1,2,4,5-四嗪)新法合成、表征与量子化学研究

自行设计了3,3’-偶氮双(6-氨基-1,2,4,5-四嗪)(DAAT)新合成路线、采用3,5-双(3,5-二甲基吡唑-1-基)-1,2,4,5-四嗪(BDT)为原料, 由文献报道的4步反应缩减为2步, 经高压氨解、高锰酸钾氧化合成了DAAT, 总收率大幅提高, 达到58.1%, 并采用元素分析、红外光谱、核磁共振光谱等进行了结构表征. 为了从分子水平探索DAAT的性能, 采用B3LYP法, 在6-31G(d,p)基组水平上对DAAT的结构进行了优化, 计算了其性能, 获得稳定的几何构型、分子轨道及键级; 在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质, 并得温度对热力学性能影响的关系式. 结果表明: DAAT分子结构中偶氮基两侧的四嗪环和氨基基本在同一个平面上, 形成一个大的共轭π键; 红外谱计算频率和强度与实验结果整体吻合较好; 热能( )、热容( )和熵( )均随温度的升高而增大.     

通过红外光谱结合化学计量学方法研究奥克托今的合成机理

通过红外(IR)光谱在线监测醋酐法合成奥克托今(HMX)的反应过程, 采用渐进因子分析(EFA)结合多元曲线分辨-交替最小二乘法(MCR-ALS)以及直观推导式演进特征投影法(HELP)等化学计量学方法对反应过程的光谱数据矩阵进行解析, 获得了各组分浓度变化曲线和对应的IR光谱; 并采用密度泛函理论(DFT)的B3LYP方法, 在6-31G^*基组水平上得到该化合物的全优化结构, 在振动分析的基础上求得体系的振动频率和IR光谱. 通过对比发现, MCR-ALS和HELP法可得出相互验证的一致结论; 将通过量子化学计算的中间体的IR光谱特征吸收峰与2种方法进行比较, 结果吻合, 从而推导出合理的反应机理. 实验结果表明, 化学计量学方法结合在线红外光谱是研究反应机理的有效手段, 对反应路线的选择具有指导意义.     

独立成分分析结合在线红外技术研究3,4-双(4'-氨基呋咱基-3')氧化呋咱的合成反应机理

利用在线红外技术监测3,4-双(4'-氨基呋咱基-3')氧化呋咱(DATF)的合成过程,并结合核独立成分分析算法对反应过程中获得的实时红外光谱数据进行解析,得到了反应物、中间体及产物各组分纯物质的红外光谱图.采用密度泛函理论B3LYP法,在6-31+G(d,p)基组水平上求得中间体的红外振动光谱,验证了所分离红外光谱图的正确性,从而推导出合理的合成反应机理.结果表明,核独立成分分析算法能合理地解析红外光谱在线数据,并有效捕捉合成反应的中间体,对合成反应机理的研究具有重要的指导意义.     

3,6-Bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine–based energetic strontium(II) complexes: synthesis,crystal structure,and thermal properties

Two energetic strontium(II) complexes with nitrogen-rich 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) were synthesized. The metal complexes were characterized by IR, elemental analysis, and single-crystal X-ray diffraction. DSC and TG-DTG were used to study the thermal behavior, non-isothermal decomposition reaction kinetics, self-accelerating decomposition temperature (T _SADT), thermal ignition temperature (T _TIT), critical temperature of thermal explosion (T _b), and the adiabatic time-to-explosion (t _TIad). The data indicate competitive energetic materials.     

1,4-二氨基-3,6-二硝基吡唑[4,3-c]并吡唑的合成、热性能及量子化学研究

以自制的3,5-二甲基-4-氨基吡唑为原料,经重氮化、环化、硝化、氧化、脱羧硝化以及N-胺化等反应合成了1,4-二氨基-3,6-二硝基吡唑[4,3-c]并吡唑(LLM-119),采用红外光谱、核磁共振、质谱及元素分析等手段表征了中间体及目标物的结构;对4-重氮基-3,5-二甲基吡唑内盐的后处理方法进行了改进,采用冷冻结晶法代替萃取法,避免大量使用有机试剂,简化操作过程,收率由77.0%提高到86.1%;初步探讨了N-胺化反应的机理,从理论上分析了收率偏低的原因;利用DSC,TG等热分析手段研究了LLM-119的热性能,其热分解峰温为232.05℃,表明LLM-119具有较好的热稳定性;首次采用B3LYP方法,在6-31G(d,p)基组水平上对LLM-119的结构进行了全参数优化,获得其稳定的几何构型和键级;在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质,并得到了温度对热力学性能影响的关系式;用Monte-Carlo方法从理论上计算LLM-119的密度为1.85 g/cm3,与实验值接近,运用Kamlet公式预测爆速为8733.94 m/s.     

3,3’-二氰基二呋咱基醚(FOF-2)的合成、表征及量子化学研究

以3-氨基-4-酰胺肟基呋咱(AAOF)为原料, 经两次氧化、分子间醚化得到3,3’-二氰基二呋咱基醚(FOF-2), 收率90.9%, 并通过IR, 1H NMR, 13C NMR, MS, 元素分析, DSC等分析手段对其结构进行了表征. 初步探讨了硝基分子间醚化合成FOF-2的反应机理; 确定了Caro’s acid氧化、分子间醚化的最佳条件. 用B3LYP方法, 在6-31G(d,p)基组水平上对其结构进行了计算, 得到了其稳定的几何构型和键级; 在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质, 并得到了温度对热力学性能影响的关系式; 探讨了其热解机理, 计算出醚键断裂时的活化能.     

Vibrational investigation on FT-IR and FT-Raman spectra, IR intensity, Raman activity, peak resemblance, ideal estimation, standard deviation of computed frequencies analyses and electronic structure on 3-methyl-1,2-butadiene using HF and DFT (LSDA/B3LYP/B3PW91) calculations

FT-IR and FT-Raman (4000–100 cm⁻¹) spectral measurements of 3-methyl-1,2-butadiene (3M12B) have been attempted in the present work. Ab-initio HF and DFT (LSDA/B3LYP/B3PW91) calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies, IR intensities and Raman activities. Complete vibrational assignments on the observed spectra are made with vibrational frequencies obtained by HF and DFT (LSDA/B3LYP/B3PW91) at 6-31G(d,p) and 6-311G(d,p) basis sets. The results of the calculations have been used to simulate IR and Raman spectra for the molecule that showed good agreement with the observed spectra. The potential energy distribution (PED) corresponding to each of the observed frequencies are calculated which confirms the reliability and precision of the assignment and analysis of the vibrational fundamentals modes. The oscillation of vibrational frequencies of butadiene due to the couple of methyl group is also discussed. A study on the electronic properties such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The thermodynamic properties of the title compound at different temperatures reveal the correlations between standard heat capacities (C) standard entropies (S), and standard enthalpy changes (H).     

新型高能量密度化合物3,6-双(3,5-二硝基-1,2,4-三唑-1)-1,2,4,5-四嗪-1,4-二氧化物的性能预估及合成路线设计

采用C++自编译程序及组合原理,设计并筛选出一种未见报道的新型富氮类高能量密度化合物-3,6-双(3,5.二硝基.1,2,4-三唑.1)-1,2,4,5-四嗪-1,4-二氧化物,用B3LYP法,在6-31G**基组水平上得到该化合物全优化构型;在振动分析的基础上求得体系的振动频率、IR谱;通过键级分析得到热解引发键的键离解能(BDE);采用Monte-Carlo 方法预估了密度;设计等键等电子反应计算了生成焓;运用Kamlet-Jacobs公式预测爆速、爆压和爆热;运用Keshavarz 等推导的预估撞击感度H50的公式预测了撞击感度性能;并利用逆合成分析法设计其合成路线.结果表明:该化合物存在8个强吸收峰,校正后的热解引发键的BDE为264KJ·mol-1,稳定性较优;密度1.955 g·cm-3、生成焓901.72 kJ·mol-1、爆速9191.48 m·s-1、爆压39.32 GPa、爆热6705.15 j·g-1;撞击感度H50为55.85cm,低于黑索金(RDX)和奥克托今(HMx);以上性能均达到了高能量密度化合物的标准,且该化合物设计合成路线步骤较少、原料易得,有望得到广泛应用.     

Copper(II) oxalate obtained through the reaction of 1,2-ethanediol with Cu(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>·3H<Subscript>2</Subscript>O

The paper presents the experimental results of the structural investigations and thermal analysis of copper(II) oxalate, a polynuclear coordination compound, obtained by a new method, through the reaction of 1,2-ethanediol with Cu(NO₃)₂·3H₂O. The reaction between 1,2-ethanediol and Cu(NO₃)₂·3H₂O occurs, under some working conditions, with the oxidation of 1,2-ethanediol to the oxalate anion (L). The synthesized polynuclear coordination compound, [CuL·0.3H₂O]_n, was characterized by chemical analysis, electronic and vibrational spectra and thermal analysis. The thermal properties of the polynuclear coordination compound have been investigated by TG, DTG and DSC. The obtained decomposition product is CuO. Powder XRD (X-ray diffraction), IR spectroscopy and TEM (transmission electron microscopy) were used to characterize the composition, the crystalline structure and the surface morphology of the copper oxide obtained through thermolysis. The thermal conversion product, copper(II) oxide, has a microporous structure with a large specific area.     

Synthesis and Thermodynamic Properties of M2L[M=Li,Na; L=3,6-Bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine]

Two novel energetic alkalic metal salts of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz), Li₂(BTATz)·6H₂O(compound 1) and Na₂(BTATz)·2H₂O(compound 2), have been synthesized by the reaction of BTATz with lithium hydroxide or sodium hydroxide in dimethylsulfoxide(DMSO) solution, respectively, and their structures were characterized by means of elemental analysis and Fourier transform infrared spectrometry(FTIR). Moreover, the single-crystal structure of compound 1 was determined by single crystal X-ray diffraction. It crystallizes in the monoclinic space group P1/c. Furthermore, their thermal decomposition behaviors were investigated by means of differential scanning calorimetry(DSC) and thermogravimetry-differential thermal gravimetry(TG-DTG). The results show that the exothermic decomposition peak temperatures for compounds 1 and 2 were 642.65 and 644.46 K, respectively, and the kinetic equations of the main exothermic decomposition were also derived from non-isothermal method. Additionally, the thermal safety of the two compounds was evaluated by calculating self-accelerating decomposition temperature(T_SADT) and critical temperature of thermal explosion(T_b). The results(the T_SADT and T_b values are 605.43 and 635.69 K for compound 1; 607.38 and 638.96 K for compound 2) reveal that the two compounds exhibit better thermal safety than BTATz.     

3,6-双(1-氢-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪银盐的热分解反应动力学及热安全性

利用两步合成法,得到标题化合物3,6-双(1-氢-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪(BTATz)银盐（Ag2(BTATz)·2H2O）,并用元素分析、X荧光和红外光谱分析对其进行了结构表征。 采用DSC和TG-DTG技术对化合物进行热分解行为及非等温热分解动力学研究。 结果表明,其热分解过程是由1个吸热阶段和2个放热阶段组成,主放热阶段的非等温热分解反应动力学方程为:dα/dt=1014.29×{3(1-α)[-ln(1-α)]1/4/4}exp(-2.10×104/T)。 计算得到化合物的自加速分解温度(TSADT)、热爆炸临界温度(Tb)、热点火温度(TTIT)和绝热至爆时间（tTIAD）分别为517.10 K、580.12 K、531.00 K和90.32 s ,以此来评价其热安全性。     

Energetic calcium(II) complexes of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)1,2,4,5-tetrazine: synthesis,crystal structure,and thermal properties

We synthesized two calcium salts of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz): [Ca₂(BTATz)₂(H₂O)₈·6H₂O] (1) and Ca(BTATz)(phen)(H₂O)₅·4H₂O (2). Complexes 1 and 2 were characterized by elemental analysis, Fourier transform infrared spectrometry, and single-crystal X-ray diffraction. Structural analysis revealed that Ca(II) was present in different coordination structures in the two complexes. Complex 1 exhibited a symmetric octahedral coordination that included three nitrogens and five water molecules. Complex 2 formed an asymmetric seven-coordinate structure with calcium connected to nitrogen in BTATz and to oxygens. The thermal behaviors of 1 and 2 were characterized via differential scanning calorimetry and thermogravimetry–differential thermal gravimetry. The peak thermal decomposition temperatures of 1 and 2 was 557.39 and 573.86 K, respectively. The kinetic equations of the main exothermic decomposition reaction were also derived. Moreover, the thermal safety of the complexes was evaluated by calculating some important thermodynamic parameters, such as self-accelerated decomposition temperature, thermal ignition temperature, and critical temperature of thermal explosion. Results indicated that both complexes exhibit good potential as a propellant component.     

Synthesis,spectral, DFT calculations and antibacterial studies of Fe(III) complexes of new fluorescent Schiff bases derived from imidazo[4',5':3,4]benzo[1,2‐c]isoxazole

New fluorescent heterocyclic ligands were synthesized by the reaction of 8‐(4‐chlorophenyl)‐3‐alkyl‐3H‐imidazo[4',5':3,4]benzo [1,2‐c]isoxazol‐5‐amine with p‐hydroxybenzaldehyde and p‐chlorobenzaldehyde in good yields. The coordination ability of the ligands with Fe³⁺ ion was examined in an aqueous metanolic solution. Schiff base ligands and their metal complexes were characterized by elemental analyses, IR, UV–vis, mass, and NMR spectra. The optical properties of the compounds were investigated and the results showed that the fluorescence of all compounds is intense and their obtained emission quantum yields are around 0.15 – 0.53. Optimized geometries and assignment of the IR bands and NMR chemical shifts of the new complexes were also computed by using density functional theory (DFT) methods. The DFT‐calculated vibrational wavenumbers and NMR chemical shifts are in good agreement with the experimental values, confirming suitability of the optimized geometries for Fe(III) complexes. Also, the 3D‐distribution map for HOMO and LUMO of the compounds were obtained. The new compounds showed potent antibacterial activity and their antibacterial activity (MIC) against Gram‐positive and Gram‐negative bacterial species were also determined. Results of antibacterial test revealed that coordination of ligands to Fe(III) leads to improvement in the antibacterial activity.     

New samarium(III) complex of 5‐aminoorotic acid with antioxidant activity

A samarium(III) complex (SmAOA) of 5‐aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt and ligand in a molar ratio of 1:3. The structure of the complex was determined by means of elemental analysis and UV–visible, NMR, Fourier transform infrared (FT‐IR) and FT Raman spectroscopies. Significant differences in the FT‐IR and FT Raman spectra of the complex were observed as compared to the spectra of the free ligand. Detailed vibrational analysis of HAOA and Sm(III)–AOA systems revealed that the binding mode in the complex was bidentate through the carboxylic oxygen atoms. The newly synthesized SmAOA showed antioxidant properties. The antioxidant activities of both HAOA and SmAOA were related to their electron donor properties. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,spectroscopy, X-ray crystal structure,and DFT studies on a platinum(II) Schiff-base complex

[PtCl₂(SMe₂)₂] reacts with (N,N′-bis(salicylidene)-1,2-cyclohexanediamine) to give (N,N′-bis(salicylidene)cyclohexane-1,2-diamine)platinum(II). The complex has been characterized by elemental analysis, infrared (IR), UV-Vis, and single-crystal X-ray diffraction. Pt(II) is in a square-planar environment, coordinated by a chelating N₂O₂ donor. Density functional theory (DFT) calculations such as geometry optimization, vibrational frequency, electronic properties, and natural bond orbital (NBO) have been performed for the platinum compound using the OLYP method at TZP(6-311G*) basis set. The optimization calculation shows that the geometry parameters can be reproduced with the OLYP/TZP basis set. Experimental IR frequencies and calculated vibrational frequencies support each other. Time-dependent DFT has been used for absorption wavelengths and results were compared with experimental data. Moreover, NBO analysis has been performed.     

Density Functional Study of the Structure and Infrared Spectrum of Ethyl Chlorophyllide (A)

A DFT/B3LYP calculation using the 6-31G(d) basis set was performed to obtain the structure, normal vibration frequencies, and absolute IR intensities of ethyl chlorophyllide (A). The calculated structural parameters agree well with the experimental X-ray diffraction data. The role of saturated substituents in stabilization of radical ion states of chlorophyll is discussed. The effective force field of ethyl chlorophyllide (A) was obtained in independent and dependent internal coordinates. The IR vibrational spectrum is modeled. The experimental IR spectrum of chlorophyll (A) is interpreted on the basis of the calculation.     

Substituent effects on benzdiyne: a density functional theory study

Density functional theory (DFT) studies were performed to investigate the effect of substituents on the properties of benzdiyne derivatives. Twelve substituted benzdiynes-C(6)X(2), where X = F, Cl, Br, Me, CF(3), CN, OH, NO(2), NH(2), OMe, NMe(2), and Ph-were considered along with the unsubstituted 1,4-benzdiyne. The structures, vibrational frequencies, and IR intensities of these benzdiynes were studied with a popular three-parameter hybrid density functional (B3LYP) combined with the split-valence 6-31G(d) basis set and Dunning's correlation-consistent polarized triple-zeta (cc-pVTZ) basis set. The relative stabilities of the substituted benzdiynes were studied with the help of reaction energies of isodesmic reactions, which showed that the electron-withdrawing groups destabilized the benzdiynes more than they did the corresponding benzenes, whereas the electron-donating groups stabilized the benzdiynes more than they did their benzene counterparts. Correlation analyses revealed that field/inductive effects played a more important role than did resonance effects. The changes in atomic charges and spin populations due to the substituents were also studied. The asymmetric nu(Ctbd1;C) stretching modes obtained were close to the 1500-cm(-)(1) mark. Reinvestigation of the experimental results supported these results; a weak IR band at 1486 cm(-)(1) was assigned to this asymmetric stretching mode in C(6)(CF(3))(2) F. Some other benzdiynes also had large IR intensity values for their asymmetric nu(Ctbd1;C) vibrational modes due to the coupling with other vibrational modes. Heats of formation for the substituted benzdiynes were obtained from the reaction energies calculated at the B3LYP/cc-pVTZ level of theory.     

Vibrationally quantum-state-specific dynamics of the reactions of CN radicals with organic molecules in solution

The dynamics of reactions of CN radicals with cyclohexane, d(12)-cyclohexane, and tetramethylsilane have been studied in solutions of chloroform, dichloromethane, and the deuterated variants of these solvents using ultraviolet photolysis of ICN to initiate a reaction. The H(D)-atom abstraction reactions produce HCN (DCN) that is probed in absorption with sub-picosecond time resolution using ～500 cm(-1) bandwidth infrared (IR) pulses in the spectral regions corresponding to C-H (or C-D) and C≡N stretching mode fundamental and hot bands. Equivalent IR spectra were obtained for the reactions of CN radicals with the pure solvents. In all cases, the reaction products are formed at early times with a strong propensity for vibrational excitation of the C-H (or C-D) stretching (v(3)) and H-C-N (D-C-N) bending (v(2)) modes, and for DCN products there is also evidence of vibrational excitation of the v(1) mode, which involves stretching of the C≡N bond. The vibrationally excited products relax to the ground vibrational level of HCN (DCN) with time constants of ～130-270 ps (depending on molecule and solvent), and the majority of the HCN (DCN) in this ground level is formed by vibrational relaxation, instead of directly from the chemical reaction. The time-dependence of reactive production of HCN (DCN) and vibrational relaxation is analysed using a vibrationally quantum-state specific kinetic model. The experimental outcomes are indicative of dynamics of exothermic reactions over an energy surface with an early transition state. Although the presence of the chlorinated solvent may reduce the extent of vibrational excitation of the nascent products, the early-time chemical reaction dynamics in these liquid solvents are deduced to be very similar to those for isolated collisions in the gas phase. The transient IR spectra show additional spectroscopic absorption features centered at 2037 cm(-1) and 2065 cm(-1) (in CHCl(3)) that are assigned, respectively, to CN-solvent complexes and recombination of I atoms with CN radicals to form INC molecules. These products build up rapidly, with respective time constants of 8-26 and 11-22 ps. A further, slower rise in the INC absorption signal (with time constant >500 ps) is attributed to diffusive recombination after escape from the initial solvent cage and accounts for more than 2/3 of the observed INC.     

一种新型含能材料s-四嗪钴盐的合成、热分解动力学及热安全性

四嗪类含能化合物因其高能、钝感、高燃速、低压力指数、良好的热安定性等特点被广泛应用于含能材料领域。然而却存在低密度、低热稳定性的问题,为提高四嗪类化合物的这一性能,制备的一系列金属衍生物得到了广泛关注。3,6-双(1-氢-1,2,3,4-四唑-5-氨基)-1,2,4,5-四嗪(BTATz)作为四嗪类高氮含能化合物一种,具有良好的催化性能及应用前景。本文以BTATz钾与硝酸钴在水溶液中反应合成了1,2,4,5-四嗪(s-四嗪)的钴盐。采用元素分析(EA)、傅里叶变换红外光谱分析(FTIR)及电感耦合等离子体质谱(ICP-MS)对其进行了结构表征,推测其化学式为Co(C_4H_2N_(14))·4H_2O。采用差示扫描量热仪(DSC)和热重分析仪(TG/DTG)研究了其热分解行为及主放热反应的动力学方程。计算了自加速分解温度(T_(SADT))、热爆炸临界温度(T_b)、热点火温度(T_(TIT))和绝热至爆时间(t_(TIAD)),其值分别为509.69 K、556.31 K、524.93 K和88.40 s,并以此来评价化合物的热安全性。该金属盐的绝热至爆时间大于相应的Ca盐、Mg盐和Sr盐,放热量高于配体BTATz,有望成为良好的燃烧催化剂。