Comparative Static and Dynamic Study of a Prototype SN2 Reaction

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• 作者：Laurent Joubert ; Michele Pavone ; Vincenzo Barone ; Carlo Adamo
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2006
• 出版时间：September 2006
• 年：2006
• 卷：2
• 期：5
• 页码：1220 - 1227
• 全文大小：110K
• 年卷期：v.2,no.5(September 2006)
• ISSN：1549-9626

文摘

Ab initio molecular-dynamic simulations, using density functional theory (DFT) andthe recent atom-centered density-matrix propagation method (ADMP), were used to study thebond formation process in a prototypical S_N2 reaction, namely the Walden inversion. Using thereal space partition schemes of both electronic density and electron localization function gradientfields, we analyzed different quantum chemical topology (QCT) properties along the ADMPtrajectory. In particular, atomic charges derived from the Bader's atoms-in-molecules (AIM) theorywere used to analyze intra- and intermolecular charge transfers between atoms, while theelectronic population of the forming bonding basin obtained from the electron localization function(ELF) gradient field was employed to describe the bond formation process. These results werecompared to the corresponding QCT properties issuing from a static approach based on theintrinsic reaction path (IRP). Although similar features are found for both static and dynamicapproaches, the dynamic QCT analysis provides some explanation of the differences observedduring the formation of the ion-molecule complex. In particular, it suggests a stronger electronexchange leading to an effective maximization of both covalent and noncovalent interactions.