Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain.
Chem Soc Rev. 2015 Sep 21;44(18):6434-51. doi: 10.1039/c5cs00066a. Epub 2015 Apr 10.
Aromaticity cannot be measured directly by any physical or chemical experiment because it is not a well-defined magnitude. Its quantification is done indirectly from the measure of different properties that are usually found in aromatic compounds such as bond length equalisation, energetic stabilisation, and particular magnetic behaviour associated with induced ring currents. These properties have been used to set up the myriad of structural-, energetic-, and magnetic-based indices of aromaticity known to date. The cyclic delocalisation of mobile electrons in two or three dimensions is probably one of the key aspects that characterise aromatic compounds. However, it has not been until the last decade that electron delocalisation measures have been widely employed to quantify aromaticity. Some of these new indicators of aromaticity such as the PDI, FLU, ING, and INB were defined in our group. In this paper, we review the different existing descriptors of aromaticity that are based on electron delocalisation properties, we compare their performance with indices based on other properties, and we summarise a number of applications of electronic-based indices for the analysis of aromaticity in interesting chemical problems.
芳香性不能通过任何物理或化学实验直接测量，因为它不是一个明确定义的量。它的量化是通过测量通常在芳香化合物中发现的不同性质来间接完成的，例如键长均等化、能量稳定化和与诱导环电流相关的特殊磁行为。这些性质已被用于建立迄今为止已知的众多基于结构、能量和磁性的芳香性指数。在二维或三维空间中，可移动电子的环状离域可能是芳香化合物的特征之一。然而，直到最近十年，电子离域测量才被广泛用于量化芳香性。我们小组定义了一些新的芳香性指标，如 PDI、FLU、ING 和 INB。在本文中，我们回顾了基于电子离域性质的不同现有芳香性描述符，比较了它们与基于其他性质的指数的性能，并总结了基于电子的指数在分析有趣化学问题中的芳香性方面的一些应用。
