Torres-Vega Juan J, Vásquez-Espinal Alejandro, Caballero Julio, Valenzuela María L, Alvarez-Thon Luis, Osorio Edison, Tiznado William
Departamento de Ciencias Químicas, Facultad de Ciencias Exactas Universidad Andres Bello , República 275, Santiago, Chile.
Inorg Chem. 2014 Apr 7;53(7):3579-85. doi: 10.1021/ic4030684. Epub 2014 Mar 17.
Although aromaticity is a concept in chemistry, in the last years, special efforts have been carried out in order to propose theoretical strategies to quantify it as a property of molecular rings. Among them, perhaps the computation of nucleus independent chemical shifts (NICSs) is the most commonly used, since it is possible to calculate it in an easy and fast way with most used quantum chemistry software. However, contradicting assignments of aromaticity by NICS and other methods have been reported in the literature, especially in studies concerning inorganic chemistry. In this Article is proposed a new and simple strategy to use the NICS information to assess aromaticity, identifying the point along the axis perpendicular to the molecular plane where the in-plane component of NICS becomes zero; it is called free of in-plane component NICS (FiPC-NICS). This spatial point is proposed as secure to consider NICS as an aromaticity descriptor; this simple proposal is evaluated in borazine and cyclotriphosphazenes. The results are compared with carefully examined aromatic stabilization energies and magnetically induced current-density analysis.
尽管芳香性是化学中的一个概念，但在过去几年里，人们为提出将其量化为分子环性质的理论策略付出了特别的努力。其中，核独立化学位移（NICS）的计算可能是最常用的，因为使用大多数常用的量子化学软件就可以轻松快速地计算它。然而，文献中报道了NICS和其他方法对芳香性的矛盾归属，特别是在涉及无机化学的研究中。在本文中，提出了一种新的简单策略，利用NICS信息评估芳香性，确定沿垂直于分子平面的轴上NICS的面内分量变为零的点；它被称为无面内分量NICS（FiPC-NICS）。这个空间点被提议作为将NICS视为芳香性描述符的可靠依据；这个简单的提议在硼嗪和环三磷腈中进行了评估。结果与经过仔细检验的芳香稳定能和磁诱导电流密度分析进行了比较。
