氮苄叉基苯胺分子的平面扭曲驱动力的DFT研究  

DFT Study of Driving Force for Distorting Benzylideneaniline Molecule Away from Planar Geometry

作　　者：马艳平[1] 包鹏[1] 虞忠衡[1] 

机构地区：[1]中国科学院化学研究所分子动态稳态国家重点实验室,北京100080

出　　处：《化学学报》2006年第13期1304-1308,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20472088;20272063)资助项目.

摘　　要：为了探索DFT方法中氮苄叉基苯胺分子的扭曲驱动力,通过把非平面氮苄叉基苯胺(NBA)分子的DFT能量分成π和σ的方法,分析了垂直离域能?EV(θ)及σ-π轨道作用能?Eσπ(θ)的失稳定性,并讨论了在扭曲过程中它们所起的作用.在B3LYP/6-31G*,6-311G*,6-31G(2d),6-311G(2d)水平下的计算结果显示:与经典观点不同,π电子的离域是失稳定的,且平面时失稳定性最强,是分子扭曲的动力;但σ-π轨道作用也是失稳定的,随着扭角的增大其失稳定性增强,是分子扭曲的阻力.NBA分子的大扭角构象,是包含π-π,σ-π轨道作用在内的各种电子相互作用共同作用的结果.In order to understand the nature of the driving force for distorting the non-planar molecule benzylideneaniline （NBA） away from its planar geometry, two energy effects, the vertical resonance energy △E^V（θ） and the δ-π orbital interaction energy AE^δπ（0）, were calculated with the DFT method, and then partitioned into their π and δ parts, denoted as △E^V-π（θ） and △E^V-δ（θ）, △E^（δπ）-π（θ） and △E^（δπ）-π（θ） respectively. △E^V（θ） is always destabilizing, and has a tendency to distort NBA molecule away from its planar geometry as far as possible. Similarly, △E^δπ（θ） is also destabilizing, however, it is most destabilizing at the θ=90° geometry. NBA molecule would prefer the θ=90° geometry if there were no interaction between the δ and π systems. The fact dE^T（θ）/dθ=0 （total energy） around θ=40° geometry, is a compromise between the various orbital interactions including π-π, δ-πinteractions.

关 键 词：能量分解 密度泛函理论 垂直离域能 δ-π轨道作用能 氮苄又基苯胺 

分 类 号：O621.25[理学—有机化学]