Furer V L, Vandyukova I I, Majoral J P, Caminade A M, Kovalenko V I
Kazan State Architect and Civil Engineering University, Zelenaya, 1, Kazan 420043, Russia.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Oct;65(2):358-65. doi: 10.1016/j.saa.2005.11.011. Epub 2006 Mar 23.
FT-IR spectra of the phosphorus-containing dendron G'(0v) generation with terminal aldehyde groups have been recorded. The structural optimization and normal mode analysis are performed for the G'(0v) on the basis of the ab initio density functional theory. This calculations gave vibrational frequencies and infrared intensities for the t,g,g- and t,-g,g-conformers of the G'(0v). The t,-g,g-conformer is 0.71 kcal/mol less stable compared to t,g,g-conformer. Relying on DFT calculations a complete vibrational assignment is proposed for different parts of the dendron. The influence of encirclement on band frequencies and intensity is studied and the information usually inaccessible is obtained. The global and local reactivity descriptors have been used to characterize the reactivity pattern of the core function and terminal groups. Our study reveals that the most reactive site in the dendron is the core function and the CH(2) side of the vinyl group is preferred for nucleophilic attack. In the dendrimer the most reactive are the terminal groups.
已记录了带有末端醛基的含磷树枝状分子G'(0v) 代的傅里叶变换红外光谱。基于从头算密度泛函理论对G'(0v) 进行了结构优化和正则模式分析。这些计算给出了G'(0v) 的t,g,g-和t,-g,g-构象异构体的振动频率和红外强度。与t,g,g-构象异构体相比,t,-g,g-构象异构体的稳定性低0.71千卡/摩尔。依靠密度泛函理论计算,为树枝状分子的不同部分提出了完整的振动归属。研究了包围对谱带频率和强度的影响,并获得了通常难以获得的信息。使用全局和局部反应性描述符来表征核心官能团和末端基团的反应模式。我们的研究表明,树枝状分子中反应性最强的位点是核心官能团,亲核攻击优先选择乙烯基的CH(2) 侧。在树枝状大分子中,反应性最强的是末端基团。