School of Science, Beijing Institute of Technology, Beijing 100081, China.
J Org Chem. 2010 Dec 3;75(23):8252-7. doi: 10.1021/jo1020097. Epub 2010 Nov 3.
Quantitative evaluations of the aromaticity (antiaromaticity) of neutral exocyclic substituted cyclopropenes (HC)(2)C=X (X = BH to InH (group 13), CH(2) to SnH(2) (group 14), NH to SbH (group 15), O to Te (group 16)) by their computed extra cyclic resonance energies (ECRE, via the block-localized wave function method) and by their aromatic stabilization energies (ASEs, via energy decomposition analyses) correlate satisfactorily (R(2) = 0.974). Electronegative X-based substituents increase the aromaticity of the cyclopropene rings, whereas electropositive substituents have the opposite effect. For example, (HC)(2)C=O is the most aromatic (ECRE = 10.3 kcal/mol), and (HC)(2)C=InH is the most antiaromatic (ECRE = -15.0 kcal/mol). The most refined dissected nucleus-independent chemical shift magnetic aromaticity index, NICS(0)(πzz), also agrees with both energetic indexes (R(2) = 0.968, for ECRE; R(2) = 0.974, for ASE), as do anisotropy of the induced current density plots.
用计算得到的外环共振能 (ECRE，通过块局域波函数方法) 和芳香稳定能 (ASE，通过能量分解分析) 对中性外取代环丙烯 (HC)(2)C=X (X = BH 到 InH (第 13 族)、CH(2) 到 SnH(2) (第 14 族)、NH 到 SbH (第 15 族)、O 到 Te (第 16 族)) 的芳香性 (反芳香性) 进行定量评估，结果令人满意 (R(2) = 0.974)。基于电负性的取代基 X 增加了环丙烯环的芳香性，而正电性取代基则有相反的效果。例如，(HC)(2)C=O 是最具芳香性的 (ECRE = 10.3 kcal/mol)，而 (HC)(2)C=InH 是最反芳香性的 (ECRE = -15.0 kcal/mol)。最精细的剖分核独立化学位移磁芳香性指数，NICS(0)(πzz)，也与这两个能量指数一致 (RECR 的 R(2) = 0.968；ASE 的 R(2) = 0.974)，诱导电流密度图的各向异性也是如此。
