Paudel Hari Ram, Karas Lucas José, Wu Judy I-Chia
Department of Chemistry, University of Houston, Houston, TX 77204, USA.
Org Biomol Chem. 2020 Jul 15;18(27):5125-5129. doi: 10.1039/d0ob01076f.
σ-Hole bonding interactions (e.g., tetrel, pnictogen, chalcogen, and halogen bonding) can polarize π-electrons to enhance cyclic [4n] π-electron delocalization (i.e., antiaromaticity gain) or cyclic [4n + 2] π-electron delocalization (i.e., aromaticity gain). Examples based on the ketocyclopolyenes: cyclopentadienone, tropone, and planar cyclononatetraenone are presented. Recognizing this relationship has implications, for example, for tuning the electronic properties of fulvene-based π-conjugated systems such as 9-fluorenone.
σ-空穴键相互作用（例如，碳族、氮族、氧族和卤族元素键）可使π电子极化，以增强环状[4n]π电子离域（即反芳香性增强）或环状[4n + 2]π电子离域（即芳香性增强）。文中给出了基于酮环多烯的示例：环戊二烯酮、卓酮和平面环壬四烯酮。认识到这种关系具有重要意义，例如，对于调节富烯基π共轭体系（如9-芴酮）的电子性质。
