全金属团簇Mg_3^(2-)芳香性的理论研究

Theoretical Study on the π-aromaticity of All-metallic Dianion Mg_3^(2-)

我们将芳香性概念扩展到全金属团簇Mg32-,运用密度泛函理论(B3LYP,B3PW91)对全金属团簇Mg32-,NaMg3-和Na2Mg3的稳定结构、振动频率与电子总能量(考虑了零点能ZPE)进行理论计算。计算的结果显示,NaMg3-和Na2Mg3团簇中包含一个正三角形的阴离子Mg32-。对芳香性的平面电子结构、核独立化位移(NICS)以及分子轨道的几个标准模式进行分析,分析的结果指出,2个离域化的π电子遵循4n+2电子计算规则,并且呈现出π芳香性。

We extended the aromaticity concept to all-metallic anion Mg32- The electronic structure of the Mg32- , NaMg3 ^- and Na2Mg^3 clusters is investigated at the B3LYP/6 -311 ＋ G（d） and B3PW91/6 -311 ＋ G（d）level of theory. The computed results indicate that NaMg^3 - and Na2B3^2- clusters contain an equilateral trigonal dianion interacting with Na atom. The aromatic character of these clusters has Mgen analyzed based on planarity, electronic stability, Nuclear Independent Chemical Shift （NICS） Values and their molecular orbitals pictures. The detailed Mos analysis further reveals that there are two delocalized π electrons which adhere to the 4n ＋ 2 electron counting rule respectively and play an important role in rendering these species the aromaticity.