Allyl Radical Nature of a Phenylcyclopentadienyl Radical Annelated with Two Homoadamantene Frameworks

1-Phenylcyclopentadiene fused with two homoadamantene units at the 2,3- and 4,5-positions (4) was deprotonated with KH to lead to the quantitative formation of the corresponding cyclopentadienyl (Cp) anion 3–. This anion was oxidized by AgCl to afford an orange crystalline solid consisting of Cp radical 3• and cyclopentadiene 4. The ESR spectrum in hexane exhibited approximately 15 lines, demonstrating that the two homoadamantene frameworks were equivalent and that the C1–C2(Ph)–C3 moiety of the five-membered ring formed a symmetrical allyl-like radical in agreement with the prediction by DFT calculation. The reaction of the Cp radical 3• with an oxygen molecule in the presence of Ag+SbF6– afforded the SbF6– salt of a phenylpyrylium ion annelated with two homoadamantene frameworks (8+SbF6–).

在2,3位与4,5位分别稠合两个同金刚烯（homoadamantene）单元的1-苯基环戊二烯（化合物4）经氢化钾（KH）去质子化后，可定量生成对应的环戊二烯基（Cyclopentadienyl, Cp）阴离子3–。该阴离子被氯化银（AgCl）氧化，得到由Cp自由基3•与环戊二烯4组成的橙色结晶固体。在己烷溶剂中测得的电子顺磁共振（Electron Spin Resonance, ESR）光谱显示约15条谱线，证明两个同金刚烯骨架等价，且五元环的C1–C2(Ph)–C3片段形成了对称的烯丙基型自由基，这与密度泛函理论（Density Functional Theory, DFT）计算的预测结果一致。Cp自由基3•在六氟锑酸银（Ag+SbF6–）存在下与氧分子发生反应，得到了带有两个同金刚烯骨架稠合的苯基吡喃鎓离子的六氟锑酸盐（8+SbF6–）。