取代基对平面环多烯烃中“超共轭”芳香性和反芳香性的影响。

Substituent effects on "hyperconjugative" aromaticity and antiaromaticity in planar cyclopolyenes.

机构信息

Departamento de Química Orgánica I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid , 28040, Madrid, Spain, and Department of Chemistry, Center for Computational Chemistry, University of Georgia , Athens, Georgia 30602, United States.

出版信息

Org Lett. 2013 Jun 21;15(12):2990-3. doi: 10.1021/ol401154r. Epub 2013 May 31.

DOI:10.1021/ol401154r

PMID:23724938

Abstract

Computed aromatic stabilization energies (ASEs) and dissected nucleus independent chemical shifts (NICSπzz) quantify the effect of hyperconjugation on the (anti)aromaticities of the planar conformations of three, five, seven, and nine membered (CnHn)CR2 (R = H, SiH3, F) rings. CH2 and especially C(SiH3)2 groups supply two "pseudo" π electrons hyperconjugatively along with the olefinic π electrons in the ring, whereas a CF2 group acts like a partially vacant p orbital. Following the Hückel rule, compounds with 4n+2 (or 4n) pseudo π electrons are "hyperconjugatively" aromatic (or antiaromatic).

摘要

计算芳香稳定能（ASE）和解析核独立化学位移（NICSπzz）量化了 hyperconjugation 对三个、五个、七个和九个成员（CnHn）CR2（R = H、SiH3、F）环的平面构象的芳香性或反芳香性的影响。CH2 尤其是 C(SiH3)2 基团与环状的烯烃 π 电子一起提供两个“伪”π 电子 hyperconjugatively，而 CF2 基团则类似于部分空的 p 轨道。根据 Hückel 规则，具有 4n+2（或 4n）个“伪”π 电子的化合物是“hyperconjugatively”芳香（或反芳香）的。