School of Science, Beijing Institute of Technology, Beijing 100081, China.
Org Lett. 2010 Mar 19;12(6):1320-3. doi: 10.1021/ol1002187.
The representative isodesmic reactions shown in the Abstract graphic for (CH)(4)X(6) hexaheteroadamantane derivatives reveal energetic nonadditivity to remarkably different extents: while the electropositive element stabilizations are exceptionally large and the pnictide and hexaoxaadamantane stabilizations are more modest, the sulfur and selenium analogues are destabilized. Similar behavior is exhibited by (CH(2))(6)X(4) tetraheteroadamantanes. Analysis shows that aromaticity is not involved; the sign and magnitude of the nonadditivity depends on the interplay of hyperconjugation, electrostatic, and steric (lone pair repulsion) effects.
摘要图形中所示的代表性等电子反应表明，（CH）（4）X（6）六杂并六环笼烷衍生物的能量非加和性程度显著不同：尽管正电性元素的稳定性非常大，磷化物和六氧杂六环笼烷的稳定性适中，但硫和硒类似物则被削弱。（CH（2））（6）X（4）四杂并六环笼烷也表现出类似的行为。分析表明，芳香性不参与其中；非加和性的符号和大小取决于超共轭、静电和空间位阻（孤对排斥）效应的相互作用。
