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首页> 外文期刊>International Journal of Quantum Chemistry >A study of the molecular structure and spectroscopic properties of polycyclic polyaza-compounds with diamond-lattice conformations
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A study of the molecular structure and spectroscopic properties of polycyclic polyaza-compounds with diamond-lattice conformations

机译：具有金刚石-晶格构象的多环多氮杂化合物的分子结构和光谱性质的研究

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摘要

The equilibrium structures of a selection of polycyclic polyaza-compounds, characterized by diamond-lattice arrangements and conformational flexibility, were investigated with the density functional method B3LYP/6-31G(d,p). The 10- or 12-membered central ring in two tricyclic tetraaza-compounds, formally derived from tricyclo-hexadecane and tricyclo-octadecane, respectively, prefers a "square" geometry. The 16- or 24-membered central ring in nonacyclic octaaza-compounds, related to pentacyclo-octacosane, and in nonacyclic dodecaaza- and hexadecaaza-compounds, both related to nonacyclo-tetratetracontane, can instead adopt two or three alternative conformations with "square" or "rectangular" geometry. The theoretical structural models are consistent with evidence from NMR and X-ray spectroscopy. In addition, they provide a satisfactory account of the C-13 NMR chemical shifts, which were predicted with a continuous set of gauge transformation calculations performed with the B3LYP/6-311+G(2d,p) formalism. The electronic structure was also studied by means of ab initio outer valence Green function calculations, which give a consistent, overall description of the different manifolds of photoionizations, associated with the nitrogen lone pair orbitals. Electron transmission spectroscopy was employed to detect the low-lying temporary anion states of some representative compounds. (C) 2001 John Wiley & Sons, Inc. [References: 32]
机译：用密度泛函方法B3LYP / 6-31G（d，p）研究了以金刚石晶格排列和构象柔韧性为特征的多环多氮杂化合物的平衡结构。分别分别正式衍生自三环十六烷和三环十八烷的两个三环四氮杂化合物中的10元或12元中心环更喜欢“正方形”几何形状。与五环-十八碳烷有关的非环状八氮杂化合物中的16或24元中心环，与非环-四十四烷均涉及的非环十二碳杂基和十六碳杂氮杂化合物中的16元或24元环可改为采用两个或三个带“正方形”的构象或“矩形”几何。理论结构模型与NMR和X射线光谱学的证据一致。此外，它们提供了C-13 NMR化学位移的令人满意的解释，这些位移通过使用B3LYP / 6-311 + G（2d，p）形式进行的连续量规转换计算来预测。还通过从头算价格林函数计算研究了电子结构，该函数对与氮孤对轨道有关的不同光电离流形给出了一致的整体描述。电子透射光谱法用于检测某些代表性化合物的低价临时阴离子状态。 （C）2001 John Wiley＆Sons，Inc. [参考：32]

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