Elucidating the ring inversion mechanism(s) for biscalixarenes.
Elucidating the ring inversion mechanism(s) for biscalixarenes.
复制标题
阐明双杯芳烃的环反转机制。
DOI：
10.1021/jp5070616
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Paterson
中科院分区：
文献类型：
--
作者：
Paul Murphy;S. Dalgarno;M. Paterson
双杯[4]芳烃可以由杯[4]芳烃通过用另一个等价部分取代亚甲基桥氢来构建。利用双杯[4]芳烃（biscal）作为前体来产生新的多金属团簇，例如单分子磁体，在数据存储和其他应用领域具有潜力。涉及biscal的多金属簇预计将优先涉及与两个金属中心（每个四酚口袋一个金属中心）的八齿结合，需要完全反转的一个环形环。在这项工作中，我们使用密度泛函理论来建立这一过程背后的机制，考虑各种能量途径，并深入了解完全和部分反转的首选途径。14个可能的途径完全反转，包括所有的过渡态（最多7个途径）。随后，最低的能量途径完全反转被发现有一个势垒高度为19.31千卡摩尔（-1）。使用PCM（有和没有SMD）和CPCM溶剂模型的溶剂优化表明，在转化过程中，长程溶剂效应可能相对不重要。本研究首次利用密度泛函理论对双杯芳烃的环反转过程进行了包括势垒高度在内的整个势能面的研究。
Biscalix[4]arene can be constructed from a calix[4]arene by substitution of a methylene bridge hydrogen by another equivalent moiety. The use of biscalix[4]arenes (biscal) as precursors for the creation of new polymetallic clusters such as single-molecule magnets has potential in the fields of data storage and other applications. Polymetallic clusters involving biscal are expected to preferentially involve octadentate binding to two metal centers (one metal center per tetraphenolic pocket), requiring full inversion of one of the annular rings. In this work, we use density functional theory to establish the mechanism behind this process, considering the various energy pathways and providing insight into the preferred route to full and partial inversion. Fourteen possible pathways to full inversion are presented, including all transition states (up to seven per pathway). Subsequently, the lowest energy pathway to full inversion was found to have a barrier height of 19.31 kcal mol(-1). Solvent optimizations using PCM (with and without SMD) and CPCM solvent models suggest long-range solvent effects may be relatively unimportant in the inversion process. This study represents the first use of density functional theory to elucidate the entire potential energy surface, including barrier heights, of the ring inversion process of biscalix[4]arenes.