偶氮四唑非金属盐的分子结构和热分解参数与其撞击感度间关联关系的研究

采用DFT 方法对偶氮四唑胍盐(GZT)等6 种偶氮四唑非金属盐进行了B3LYP/6-31G 水平的几何结构全优化, 计算了分子的最低空轨道能量(E_LUMO)、最高占有轨道能量(E_HOMO)及原子上的电荷分布等分子结构参数. 研究了偶氮四唑非金属盐的分子结构参数(包括氧平衡)和热分解参数(热分解温度和热分解活化能等)与其撞击感度之间的相关性. 结果表明, 偶氮四唑非金属盐的氧平衡越低, 撞击感度越低; 热分解温度和热分解活化能越低, 撞击感度越高; 取代基团上所带正电荷越大, 撞击感度越低.     

2,6-二(对氨基苯)苯并[1,2-d;5,4-d′]二噁唑的合成和纯化

1 ,2 ,3 三氯苯经过硝化、水解、催化加氢、缩合等四步反应 ,合成了 2 ,6 二 (对氨基苯 )苯并 [1,2 d ;5 ,4 d′]二唑 ,总产率为 70 % .同时 ,研究了一种有效的重结晶 2 ,6 二 (对氨基苯 )苯并 [1,2 d ;5 ,4 d′]二唑的方法 .与其他方法相比 ,该法原料便宜易得 ,产物可作为聚合反应的单体原料 .     

四唑互变异构反应的密度泛函理论(DFT)研究

运用11种密度泛函理论方法对四唑互变异构反应进行了计算研究。结果表明,B3LYP-DFT法与从头算的优化几何和能量最为吻合;在6-31^*基组下B3LYP计算的IR频率与MP2/6-311G^*^*计算结果相差很小;用未经校正的B3LYP计算频率求得的产物(2H-四唑)的热力学性质与实测结果也完全一致;由此推荐B3LYP-DFT法适合于对四唑化合物作系统研究。     

聚苯并双噁唑酰亚胺的热分解动力学研究

采用二步法合成了以2,6-二(对-氨基苯)苯[1,2-d;5,4-d’]二噁唑和1,4-二(3,4-二苯氧基)苯四甲酸二酐(HQDPA)为单体的聚苯并双噁唑酰亚胺.该聚酰亚胺的预聚体聚酰胺酸的黏度为1.70 dL/g,经过热环化后能够生成浅黄色的聚酰亚胺薄膜.通过热重分析法研究了聚苯并双噁唑酰亚胺在N2气氛中的热降解机理.采用Flynn-Wall-Ozawa和Friedman法计算了聚苯并双噁唑酰亚胺热降解表观活化能,分别为356.36kJ/mol和370.54 kJ/mol,平均值为363.45 kJ/mol;反应级数为4.22,指前因子为6.44×1016s-1.采用Coast-Redfern法和Phadnis-Deshpande法研究了聚苯并双噁唑酰亚胺的热降解固相反应机理,认为该聚酰亚胺的热降解机理属于反曲线(A3)机理,是成核和增长模式(Avrami equation 2方程)控制的热降解反应,积分形式为g(X)=[-ln(1-X)]3.     

含肟醚的新型四唑啉酮衍生物的合成及除草活性研究

1-(4-氯苯基)-1,4-二氢-四唑-5-酮(1)与氯丙酮反应生成1-(4-氯苯基)-4-(2-氧代丙基)-1,4-二氢-四唑-5-酮(2). 中间体2、盐酸羟胺和卤化物通过三组分一锅法合成了目标化合物3. 初步生物活性测试结果表明: 目标化合物3具有较好的除草活性.     

5-硝基-2H-四唑的合成、反应性及产物晶体结构的研究

5-氨基四唑(1)经过重氮化反应得到5-硝基四唑(5),5与甲醛反应得到2-羟甲基-5-硝基四唑(6),6与HCl或HBr反应分别得到5-5氯代四唑(7)和5-溴代四唑(8),采用MS,IR,1H NMR,13C NMR等技术对这些化合物进行了表征.用X射线单晶衍射法测定了化合物5-硝基四唑钠(4),5和6的晶体结构.化合物4属于三斜晶系,P-1空间群;化合物5和6均属于单斜晶系,P21空间群,化合物6的晶胞参数a=0.66131(18)nm,b=0.54905(15)nm,c=0.7566(2)nm,Z=2,V=0.27470(13)nm3,Dc=1.754g/cm3,F(000)=128,μ=0.160mm-1.     

聚(乙烯基四唑-co-丙烯酸)的合成与表征

以聚丙烯腈为原料,首先通过部分腈基的[3+2]合环反应转化为聚(乙烯基四唑-co-丙烯腈)[Poly(VT-co-AN)],再通过碱性水解反应将剩余的腈基转化为羧基,合成出聚(乙烯基四唑-co-丙烯酸)[Poly(VT-co-AA)]。 采用傅里叶红外变换光谱仪(FT-IR)、核磁共振碳谱仪(¹³C NMR)、酸碱滴定等方法对Poly(VT-co-AN)和[Poly(VT-co-AA)的结构进行了表征,结果表明,Poly(VT-co-AN)的分子链中含有腈基、四唑基团和部分羧基,四唑基团的含量为68.6%,与酸碱滴定法测定的四唑基团的含量相近,[Poly(VT-co-AA)中含有四唑基团和羧基,不含有腈基,酸值高于Poly(VT-co-AN),四唑基团的含量为67.6%,与叠氮化钠与聚丙烯腈的摩尔比相近。 热失重分析结果显示[Poly(VT-co-AA)的热分解速率加快,在270~285 ℃的温度区间内分解完全。     

一种新型高氮含能化合物5-((5-硝基-2H-四唑-2-基)甲基)-1H-四唑-1-醇的合成与表征

以5-氨基四唑为起始原料,经重氮化-硝化、烷基化、肟化、重氮化-氯化、叠氮化和环合等单元反应以19%的总产率合成了一种新型含能化合物5-[(5-硝基-2H-四唑-2-基)甲基]-1H-四唑-1-醇.利用NMR,IR,MS及元素分析等进行了结构表征;利用X射线单晶衍射法测试了该化合物的晶型结构,该化合物属于单斜晶系,空间群P2(1)/c,晶胞参数:a=3.3619(11),b=9.3910(19),c=8.2060(16),β=101.44(3)°,Z=2,Dc=1.748 g·cm-3,μ=0.153 mm-1,F(000)=216;利用差示扫描量热法(DSC)和热重(TG)分析研究了该化合物的热性能,分解温度为202.25℃,热重变化范围130~320℃,总失重78.6%;利用Kamlet-Jacobs公式估算了该化合物的爆轰性能,理论爆速和爆压分别为8500 m·s-1和31.53 GPa.     

2-芳基-5-(5-苯基-2H-四唑-2-亚甲基-1,3,4- 二唑类化合物的研究

本文研究了用N-(5-苯基-2H-四唑-2-乙酰基)-N'-芳酰肼制备分子中既有四唑, 1,3,4- 二唑环的2-芳基-5-(5-苯基-2H-四唑-2-亚甲基)-1,3,4- 二唑。并对化合物进行了质谱研究。     

新型5位与6位取代的吲唑类衍生物的合成及抗肿瘤活性研究

为了寻找高效低毒的新型抗肿瘤药物,设计并合成了新型的5位与6位取代的吲唑类化合物.采用噻唑蓝(MTT)法对目标化合物在PC-3(人前列腺癌细胞)、MCF-7(人乳腺癌细胞)、Hep G-2(人肝癌细胞)和MGC-803(人胃癌细胞)四种人类癌细胞的抗增殖活性进行评价.结果显示大部分化合物对PC-3具有特异性的抗增殖活性.其中,N-(1-苄基-1H-1,2,3-三唑-4-基)甲基)-1-异丙基-1H-吲哚唑-5-羧酰胺(8a)和N-[(1-苄基-1H-1,2,3-三唑-4-基)甲基]-1-异丙基-1H-吲唑-6-甲酰胺(14a)对PC-3细胞的抗增殖活性较好, IC₅₀值分别为6.21和6.43μmol/L,为前列腺癌抗肿瘤药物的研究提供了思路.     

Ab initio and DFT studies of the vibrational spectra of benzofuran and some of its derivatives

The vibrational spectra of benzofuran and some of its derivatives have been systematically investigated by ab initio and density functional B3LYP methods. The harmonic vibrational wavenumbers and intensity of vibrational bands were calculated at ab initio and DFT levels invoking different basis sets up to 6-311++g**. Vibrational assignments have been made and it has been found that the calculated DFT frequencies agree well in most cases with the observed frequencies for each molecule. Conformational studies have also been carried out and it is evident from ab initio calculations that 2(3H) benzofuranone is more stable than 3(2H) benzofuranone in support to our earlier semiempirical results.     

Conformational Analysis of 2,2′-bifuran: Correlated High-level Ab initio and DFT Results

The torsional potential for inter-ring rotation in 2,2′-bifuran has been systematically tackled using highly accurate ab initio calculations as well as cost-effective DFT methods. The successful convergence of the ab initio results allowed to confirm the presence of a shallow gauche minimum in the torsional potential curve. The standard DFT methods failed to capture such a tiny energy barrier but, interestingly, the results could be remarkably improved by a mixture of wavefunction and DFT energies in a multi-coefficient fashion; thus, accurate DFT-based and ab initio reference data also become available. Since the experimental evaluation of torsional potentials faces quantitative problems, the outcome of high-level theoretical calculations is expected to be reliably used in further investigation on structure and conformational distribution of this system.     

Calculated NMR as a tool for structural elucidation of jungianol and mutisianthol

Theoretical methods were used for the correct structure assignments of the natural products jungianol and mutisianthol. A three stage protocol for the calculation was used: a conformational search using molecular mechanics (MM3), a DFT (B3LYP) structure optimization and ab initio (HF/GIAO) or DFT (B3LYP/GIAO) calculation of magnetic properties.     

Ab initio studies on the polarizability of lithium clusters: Some unusual results

The polarizability of lithium clusters was studied using ab initio as well as Density Functional Theory (DFT)‐based methods. The electron correlation was found not to play any major role in the evaluation of polarizability of the lithium clusters, contrary to the case of sodium and other types of clusters. The theoretical methods used in the present study are not able to reproduce the unusual features in the size evolution of the polarizability observed experimentally. An interesting feature is that the polarizability of lithium clusters calculated by various methods at 0K temperature is found to be higher than the experimental results measured at higher temperature, which is quite unusual. The significance of these issues is highlighted and the need of highly accurate DFT exchange‐correlation functionals and ab initio methods in the study of the electronic properties of lithium clusters is emphasized. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Conformations and energetics of sulfur and selenium diimides

The geometries and energetics of different conformations of sulfur and selenium diimides E(NR)(2) (E = S, Se; R = H, Me, (t)Bu, C(6)H(3)Me(2)-2,6, SiMe(3)) have been studied by using various ab initio and DFT molecular orbital techniques. The syn,syn conformation is found to be most stable for parent E(NH)(2), but in general, the preferred molecular conformation for substituted chalcogen diimides is syn,anti. In the case of E(NH)(2) the present calculations further confirm that syn,syn and syn,anti conformations lie energetically close to each other. From the three different theoretical methods used, B3PW91/6-31G proved to be the most suitable method for predicting the geometries of chalcogen diimides. The optimized geometrical parameters are in a good agreement with all available experimental data. While qualitative energy ordering of the different conformations is independent of the level of theory, the quantitative energy differences are dependent on the method used. The performance and reliability of higher level ab initio calculations and DFT methods using large basis sets were tested and compared with experimental information where available. All of the higher level ab inito methods give very similar results, but the use of large basis sets with the B3PW91 method does not increase the reliability of the results. The combination of CCSD(T)/cc-pVDZ with the B3PW91/6-31G-optimized geometries is found to be the method of choice to study energetic properties of chalcogen diimides.     

荧光素及其衍生物电子结构与光谱性质的理论研究

用ZINDO、从头算和密度泛函理论方法研究荧光素及其衍生物的电子结构和光谱性质.计算结果表明母体双阴离子荧光素分子(1)与单(2)、双(3)取代形成的单阴离子荧光素分子的基态电子结构不同,而且1与2和3的基态和激发态的电子转移方向相反.体系1~3的最大吸收波长依次发生红移,与实验结果相符合.     

3-和4-苯基香豆素化合物的电子结构及光谱性质的理论研究

采用从头算、密度泛函和单激发组态相互作用理论方法研究3-和4-苯基香豆素化合物的电子结构和光谱性质,并用极化连续模型考虑了溶剂对光谱性质的影响.结果发现,在3-苯基香豆素的7-位引入给电子基团甲氧基或吸电子基团氰基均使它们的吸收光谱和荧光光谱产生红移,4-苯基香豆素的衍生物的吸收光谱和荧光光谱均产生蓝移.3-苯基香豆素衍生物与4-苯基香豆素的衍生物的基态和激发态的电子转移方向相反.计算的结果与实验结果吻合的很好.     

Infrared and Raman spectra, ab initio calculations of structure and vibrational assignment of 1-fluoro-2-butyne.

The infrared spectra (3500-50 cm(-1)) of the gas and solid and the Raman spectra (3500-50 cm(-1)) of the liquid and solid have been recorded for 1-fluoro-2-butyne, CH3-C-triple bond-C-CH2F. Equilibrium geometries and energies have been determined by ab initio and hybrid DFT methods using a number of basis sets. A vibrational assignment is proposed based on the force constants, relative intensities, depolarization ratios from the ab initio and DFT calculations and on vibrational-rotational band contours obtained using the calculated equilibrium geometries. From calculated energies it is shown that the CH3 group exhibits almost completely free rotation which is in agreement with the observation of Coriolis sub-band structure in two of the degenerate methyl vibrations. The results are compared to the corresponding quantities for some similar molecules.     

High level of ab initio and density functional theory computational study of structural and energetic properties of tetrafluorhydrazine rotamers

The HF, MP2, MP3, MP4, and QCISD ab initio methods were compared with local, hybrid, and gradient-corrected density functional theory (DFT) methods for computing structures and energies of N2F4 rotamers. In all DFT calculations 6-311 + G(2d) basis set was used. The generated structures energies of trans- and gauche-N₂F₄ rotamers, and their dissociation energies to nitrogen difluoride were compared with experimental data. Suitable hybrid and gradient-corrected DFT methods for determining structures and energies for these and similar molecular systems were discussed.