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运用密度泛函理论, 在B3LYP/6-31G*水平上, 对蒽醌及其羟基取代衍生物进行理论计算. 几何全优化的结果表明, 标题化合物均取平面构型, 分子内氢键对几何构型和电子结构影响很大. 基于简谐振动分析求得IR谱频率和强度, 并作了对称性分类和指认, 计算值与实验值良好相符. 运用含时密度泛函理论方法在相同水平上计算了标题物的电子吸收光谱, 发现蒽醌芳环取代衍生物的最低激发单重态均源自HOMO-LUMO(π→π*)跃迁. 基于振动分析, 由统计热力学求得了标题物的热力学性质. 相似文献
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用量子化学密度泛函理论方法,在B3LYP/6-31G*水平下,对六硝基芪衍生物进行了几何构型全优化和电子结构计算。通过振动分析,求得它们的红外光谱并作归属。将理论计算IR谱与已知实验结果进行比较,表明本文所提供的计算结果是可靠的。对谐振频率以0.96进行标度后基于统计热力学原理求得它们的热力学性质,探讨了热力学性质随硝基数、氨基数、羟基数和温度变化的规律,发现有很好的线性关系,体现了很好的基团加和性。 相似文献
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以1,2,3-三氨基胍盐酸盐和二硝基胍为原料,制备了一种新型含能离子盐1,2,3-三氨基胍二硝基胍盐,并对其结构进行了表征. 运用密度泛函理论(DFT)方法,在B3LYP/6-31+G**水平下计算得到了该盐的几何结构、自然原子电荷分布、前线轨道能量及红外光谱,同时计算了热容、焓及熵等热力学参数,并分析了这些参数和温度之间的函数关系;利用Born-Haber循环求得该化合物的生成热为150.54 kJ/mol;利用Monte-Carlo方法预测了该化合物的理论密度为1.56 g/cm3;基于以上数据进一步计算得到该化合物的爆速为7.81 km/s,爆压为24.74 GPa. 相似文献
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四唑互变异构反应的密度泛函理论(DFT)研究 总被引:8,自引:0,他引:8
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。 相似文献
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双环-HMX结构和性质的理论研究 总被引:7,自引:2,他引:5
在DFT-B3LYP/6-311G*水平上, 计算研究了高能化合物四硝基四氮杂双环辛烷(双环-HMX) α和β两种异构体的结构和性质. 比较分子对称性、分子内氢键和环张力等几何参数以及分子总能量和前线轨道能级等电子结构参数, 发现α比β稳定. 分子中N—N键较长, N—N键集居数较小, 预示该键为热解和起爆的引发键. 基于简谐振动分析求得IR谱频率和强度. 运用统计热力学方法求得200~1000 K温度的热力学性质. 以非限制性半经验PM3方法探讨其热解机理, 求得各反应通道的过渡态和活化能, 发现热解始于侧链N—NO2键的均裂. 还从理论上预测了该化合物的密度、爆速和爆压, 有助于寻求高能量密度材料(HEDM). 相似文献
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Teimouri A Emami M Chermahini AN Dabbagh HA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,71(5):1749-1755
The compound 4-N-bicyclo [2.2.1] hept-2'-en-2'-amino-N-azatricyclo [3.2.1.0(2,4)] octane (2) has been synthesized and characterized by elemental analysis, IR, UV-vis, mass and NMR. Density functional theory (DFT) and Hartree-Fock (HF) calculations have been carried out for the title compound by using the standard 6-31G* basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental IR spectra and they complement each other. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT and ZINDO methods. The (13)C NMR and (1)H NMR of compound (2) have been calculated by means of Becke 3-Lee-Yang-Parr (B3LYP) density functional method with 6-31G* basis set. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting NMR properties. On the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated. 相似文献
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Yu-Xi Sun Qing-Li Hao Zong-Xue Yu Wen-Jun Jiang Lu-De Lu Xin Wang 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,73(5):892-901
This work deals with the IR and Raman spectroscopy of 4-(2-furanylmethyleneamino) antipyrine (FAP), 4-benzylideneaminoantipyrine (BAP) and 4-cinnamilideneaminoantipyrine (CAP) by means of experimental and quantum chemical calculations. The equilibrium geometries, harmonic frequencies, infrared intensities and Raman scattering activities were calculated by density functional B3LYP method with the 6-31G(d) basis set. The comparisons between the calculated and experimental results covering molecular structures, assignments of fundamental vibrational modes and thermodynamic properties were investigated. The optimized molecular geometries have been compared with the experimental data obtained from XRD data, which indicates that the theoretical results agree well with the corresponding experimental values. For the three compounds, comparisons and assignments of the vibrational frequencies indicate that the calculated frequencies are close to the experimental data, and the IR spectra are comparable with some slight differences, whereas the Raman spectra are different clearly and the strongest Raman scattering actives are relative tightly to the molecular conjugative moieties linked through their Schiff base imines. The thermodynamic properties (heat capacities, entropies and enthalpy changes) and their correlations with temperatures were also obtained from the harmonic frequencies of the optimized strucutres. 相似文献
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Hanife Saraçoǧlu Alaaddin Cukurovali 《International journal of quantum chemistry》2012,112(16):2775-2781
The title molecule, N‐[4‐(3‐Methyl‐3‐phenyl‐cyclobutyl)‐thiazol‐2‐yl]‐N′‐pyridin‐3ylmethylene‐ hydrazine (C20 H20 N4 S1), was characterized by 1H‐NMR, 13C‐NMR, IR, UV‐visible, and X‐ray determination. In addition to the molecular geometry from X‐ray experiment, the molecular geometry, vibrational frequencies and gauge including atomic orbital 1H‐ and 13C‐NMR chemical shift values of the title compound in the ground state have been calculated using the Hartree‐Fock and density functional method (B3LYP) with 6‐31G(d, p) basis set. The calculated results show that optimized geometries can well reproduce the crystal structural parameters. By using time‐dependent density functional theory method, electronic absorption spectrum of the title compound has been predicted. © 2011 Wiley Periodicals, Inc. 相似文献
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Based on the optimized molecular geometries at the DFT‐B3LYP/6‐31G?? level, IR spectra, thermodynamic functions, as well as 13C and 1H NMR chemical shifts, were obtained and discussed for polynitro‐1,3‐bishomo‐pentaprismanes (PNBPP). The comparison of the calculated IR frequencies and NMR chemical shifts showed considerable agreements with the available experimental results. IR regions, 13C and 1H NMR chemical shifts of PNBPP were assigned. The relationships of the thermodynamic functions with temperature and the number of nitro groups were discussed, and it was found that the latter showed a good group additivity rule. These calculated data and discussions would be helpful for the further study of PNBPP. 相似文献
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Zhang X Liu Z Kobayashi N Jiang J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(3-4):1135-1138
Chemical shifts of some reduced symmetry peripheral fused-ring-substituted phthalocyanines, namely Zn3B1N, Zncis2B2N, Zntrans2B2N, Zn1B3N and Zn3B0N, have been calculated at density functional B3LYP level using the gauge-independent atomic orbital (GIAO) method. The geometries were optimized using the 6-31G(d) basis set and the following NMR calculations were performed using 6-31G(d) and 6-311G(d,p) basis sets, respectively. The calculated NMR shielding tensors and chemical shifts are compared with previous experimental results. The chemical shifts are assigned according to the calculated data and satisfying results are obtained. The NMR shielding tensor simulation of Zn3B0N has been raised as a significant theoretical topic. 相似文献
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9-(4,5-二硫甲基-1,3-二硫杂环戊烯-2甲叉基)蒽-10(9H)-酮的合成及量子化学计算 总被引:3,自引:0,他引:3
设计合成了一种新的具有D-π-A结构的有机分子,9-(4,5-二硫甲基-1,3- 二硫杂环戊烯-2-甲叉基)蒽-10(9H)-酮(C_(19)H_(14)OS_4)。以~1H NMR, FTIR,元素分析和UV-vis进行了表征。运用Gaussian 98量子化学程序包,采用 B3LYP密度泛函(DFT)的方法,在6-31G(d)水平上对分子的几何构型进行了优化 ,在优化的基础上用TDDFT的方法计算了化合物的电了防染印花谱,计算值与实验 值基本吻合,用TDHF的方法计算了它的二阶非线性光学系数,与蒽醌相比,其第一 超给化率β较大,为12.03 * 10~(-30)esu。 相似文献
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Theoretical investigation of nitro derivatives of tetrazole with density functional theory (DFT) 总被引:3,自引:0,他引:3
The B3LYP of density function theory (DFT) method was employed to calculate seven nitrotetrazoles. The optimized geometries, IR spectra and thermodynamic properties at 6-31G* level are obtained. Their heats of formation were computed accurately using the designed isodemic and isogyric reactions. The calculated total energies and heats of formation consistently show that C-nitrotetrazoles are more stable than the N-isomers. 相似文献
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利用红外光谱研究不同温度下CaCl2/甲醇溶液体系的溶剂化作用,结果表明在溶液中CaCl2以离子形式与甲醇发生溶剂化作用,且溶剂化数随温度升高而降低.通过密度泛函理论(DFT)在B3LYP/6-31G**水平下对CaCl2/甲醇溶液中可能存在的配位构型进行结构优化及热力学性质的计算,说明了在CaCl2/甲醇溶液中各种配位构型存在的可能性,得出温度升高热力学数据的变化规律,解释了溶剂化数随温度升高而降低的趋势.进一步对各种可能配位构型的红外吸收频率进行计算并与实验结果进行比较,推断在CaCl2/甲醇溶液中主要存在的配位构型为[CaCl(CH3OH)n]+和[Cl(CH3OH)n]-. 相似文献
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Morkan IA Morkan AU 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1715-1721
The optimized molecular structure, atomic charges, vibrational frequencies, thermodynamic properties, nuclear magnetic resonance (NMR) and ultraviolet-visible (UV-Vis) spectral data of pentacarbonyl(4-methylpyridine)chromium(0) complex have been investigated by performing ab initio Hartree-Fock (HF) and density functional theory, B3LYP, B3PW91 and BE1PBE methods with 6-311G, 6-311+G(3d,3p) and 6-31G(d,p) basis set. The calculated NMR data at 6-311G basis set, vibrational frequencies at 6-311+G(3d,3p) basis set and the optimized geometric bond lengths and bond angles at 6-31G(d,p) basis set are in good agreement with the corresponding experimental values. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) have been simulated. In addition, the transition state and energy band gap and infrared intensities have also been reported. 相似文献
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设计合成了一种新的具有D-π-A体系的有机分子:3-(4,5-二苄硫基-1,3-二硫杂环戊烯-2-亚基)萘吡喃酮,通过UV-vis,1H NMR,13C NMR,TOFMS和IR确定了其结构.初步研究了该化合物的电子光谱、荧光光谱和热稳定性.运用Gaussian 03量子化学程序包,采用密度泛函(DFT)B3PW91的方法优化了其基态几何结构,得到的几何参数与实验结果吻合得很好.研究结果表明,体系中存在着分子内的电荷转移,有较好的荧光性质,为寻找新的发光材料具有一定的实际意义. 相似文献