共查询到16条相似文献,搜索用时 93 毫秒
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邻氨基苯甲酰叠氮及其衍生物热分解反应的量子化学研究 总被引:5,自引:1,他引:4
叠氮化合物是良好的炸药和火箭推进剂 ,在国防和工农业生产中有着广泛的应用 [1] .近年来 ,化学工作者对此类化学反应的进展极为关注 [2 ,3 ] .为从理论上阐明此类反应的机理 ,我们对甲酰基和苯甲酰基叠氮的热分解反应进行了研究 [4] .本文报道了用 UHF/AM1方法[5 ] 研究邻氨基苯甲酰叠氮、邻氨基间甲基苯甲酰叠氮和邻氨基间甲醛基苯甲酰叠氮热分解反应的结果 .1 计算方法反应物 ( Re)、中间体 ( )和产物 ( P)的几何构型用能量梯度法全优化计算 ;对于过渡态 ,先用极小能量途径法寻找初始构型 ,然后再用本征矢跟踪 EF( Eigenvector Fo… 相似文献
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水杨醛缩苯胺类席夫碱构象异构体的稳定性及其非线性光学性质的理论研究 总被引:7,自引:0,他引:7
运用量子化学有限场FF/PM3方法,对水杨醛缩苯胺类席夫碱几种异构体稳定构象的能量、结构、非线性光学系数进行了分析,探讨氢键及氢迁移过程对体系稳定性和非线性光学性质的影响.结果表明:水杨醛缩苯胺类席夫碱分子具有较好的二阶非线性光学性质,并可能成为一类良好的光学材料. 相似文献
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扶手椅型单壁碳纳米管生长机理的理论研究 总被引:1,自引:0,他引:1
用Gaussian03程序中的AM1方法对扶手椅型单壁碳纳米管的生长机理进行了研究. 结果表明, 若碳纳米管生长的碳源是C2自由基, 则有一条反应途径可能是:C2自由基首先与碳纳米管的开口端形成一个中间体, 然后该中间体经过一个过渡状态, 形成产物;从(3, 3), (4, 4), (5, 5)到(6, 6), 其生长反应的活化能逐渐降低. 同时 研究发现, 活化能的高低与碳纳米管共轭程度的大小有关, 碳纳米管的共轭程度越大, 活化能越低;在靠近新形成的六元环的两侧, 碳纳米管可能优先继续生长. 相似文献
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Mehmet Kabak 《Journal of Molecular Structure》2003,655(1):135-139
N,N′-bis(3,5-dichlorosalicylidene)-2-hydroxy-1,3-diamino-2-propan (C17H14Cl4N2O3) was synthesized and its crystal structure determined. It crystallizes in the monoclinic space group, C2/c, with a=29.734(8), b=4.541(1), c=14.694(2) Å, β=115.85(2), R(F2)=0.048 for 1704 independent reflections. The title compound has a twofold axis passing through the central C9 atom. The intramolecular hydrogen bond occurs between the pairs of atoms N1 and O1 [2.648(5) Å] and the hydrogen atom is essentially being bonded to the nitrogen atom. There is no intermolecular proximity between molecules. Conformations of the title compound were investigated by semi-empirical quantum mechanical AM1 calculations. The optimized geometry of the molecular structure corresponding to the non-planar conformation is the most stable conformation in the theoretical calculations. The results strongly indicate that the minimum energy conformation is primarily determined by non-bonded steric interactions. 相似文献
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A. Elmali M. Kabak E. Kavlakoglu Y. Elerman T. N. Durlu 《Journal of Molecular Structure》1999,510(1-3):207-214
The crystal structure of N-(2-hydroxy-5-chlorophenyl) salicylaldimine (C13H10NO2Cl) was determined by X-ray analysis. It crystallizes orthorhombic space group P212121 with a=12.967(2) Å, b=14.438(3) Å, c=6.231(3) Å, V=1166.5(6) Å3, Z=4, Dc=1.41 g cm−3 and μ(MoK)=0.315 mm−1. The title compound is thermochromic and the molecule is nearly planar. Both tautomeric forms (keto and enol forms in 68(3) and 32(3)%, respectively) are present in the solid state. The molecules contain strong intramolecular hydrogen bonds, N1–H1O1/O2 (2.515(1) and 2.581(2) Å) for the keto form and O1–H01N1 for the enol one. There is also strong intermolecular O2–HO1 hydrogen bonding (2.599(2) Å) between neighbouring molecules. Minimum energy conformations AM1 were calculated as a function of the three torsion angles, θ1(N1–C7–C6–C5), θ2(C8–N1–C7–C6) and θ3(C9–C8–N1–C7), varied every 10°. Although the molecule is nearly planar, the AM1 optimized geometry of the title compound is not planar. The non-planar conformation of the title compound corresponding to the optimized X-ray structure is the most stable conformation in all calculations. 相似文献
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N-(2-hydroxyphenyl)-4-amino-3-penten-2-on (C11H13NO2) has been studied by X-ray analysis. It crystallizes the orthorhombic space group P212121 with a=8.834(1), b=10.508(2), c=11.212(2) Å, V=1040.8(3) Å3, Z=4, Dc=1.22 g cm−3 and μ(MoK)=0.084 mm−1. The structure was solved by direct methods and refined to R=0.038 for 1373 reflections (I>2σ(I)). The title compound is photochromic and the molecule is not planar. Intramolecular hydrogen bonds occur between the pairs of atoms N(1) and O(1) [2.631(2) Å], and N(1) and O(2) [2.641(2) Å], the H atom essentially being bonded to the N atom. There is also a strong intermolecular O–HO hydrogen bonding [2.647(2) Å] between neighbouring molecules. Tautomeric properties and conformations of the title compound were investigated by semi-empirical quantum mechanical AM1 calculations and the results are compared with the X-ray results. 相似文献