Extended hypervalent E′⋯E–E⋯E′ 4c–6e (E, E′ = Se, S) interactions: structure, stability and reactivity of 1-(8-PhE′C10H6)EE(C10H6E′Ph-8′)-1′
作者:Waro Nakanishi、Satoko Hayashi、Sayuri Morinaka、Takahiro Sasamori、Norihiro Tokitoh
DOI:10.1039/b805678a
日期:——
The structure, stability and reactivity of Eâ²â¯EâEâ¯Eâ² (E2Eâ²2) 4câ6e are examined employing naphthalene 1,8-positions in 1-(8-PhEâ²C10H6)EE(C10H6Eâ²Ph-8â²)-1â² [1 (E = Se, Eâ² = S), 2 (E = S, Eâ² = Se), 3 (E = Eâ² = Se) and 4 (E = Eâ² = S)], together with 1-C10H7EEC10H7-1â² [5 (E = Se) and 6 (E = S)]. Linear alignments of four Se2S2 atoms in 1 and 2 are confirmed by the X-ray analysis. 1 was not reduced by sodium borohydride, whereas 2 was, contrary to the expectation. Similarly, EâE in 3, 5 and 6 were cleaved, whereas that in 4 was not, when allowed to react with NaBH4 in aqueous THF. The reactivity of the EâE bonds in E2Eâ²2 in 1â4 is not controlled by the central E atoms but by the outside Eâ² atoms. Quantum chemical (QC) calculations are performed on 1-(8-MeEâ²C10H6)EE(C10H6Eâ²Me-8â²)-1â² (13â16: models of 1â4, respectively), 5 and 6, together with the related species. Conformers having E2Eâ²2 4câ6e (abbreviated by BA) are the global minima for 13, 15 and 16, which reproduces the observed structures: BA must be stabilized by the formation of E2Eâ²2 4câ6e. 14 (AB) with double n(S)â¯Ï*(SeâC) 3câ4e interactions is the global minimum, which shows that Ï*(SeâC) plays a crucial role to stabilize the 3câ4e in AB. The novel reactivity of EâE is considered based on the QC calculations.
利用 1-(8-PhEâ²C10H6)EE(C10H6Eâ²Ph-8â²)-1â² [1 (E = Se. Eâ² = S)、2 (E = S, Eâ² = Se)、3 (E = Eâ² = Se)和 4 (E = Eâ² = S)中的萘 1,8 位,研究了 Eâ²â¯EâEâ¯Eâ² (E2Eâ²2) 4câ6e 的结构、稳定性和反应性、Eâ²=S)、2(E=S,Eâ²=Se)、3(E=Eâ²=Se)和 4(E=Eâ²=S)],以及 1-C10H7EEC10H7-1â² [5(E=Se)和 6(E=S)]。X 射线分析证实了 1 和 2 中四个 Se2S2 原子的线性排列。1 没有被硼氢化钠还原,而 2 则被还原,这与预期相反。同样,3、5 和 6 中的 EâE 与 NaBH4 在四氢呋喃水溶液中发生反应时会裂解,而 4 中的 EâE 不会裂解。1â4 中 E2Eâ²2 中 EâE 键的反应性不是由中心 E 原子控制的,而是由外部 Eâ² 原子控制的。我们对 1-(8-MeEâ²C10H6)EE(C10H6Eâ²Me-8â²)-1â²(13â16:分别为 1â4 的模型)、5 和 6 以及相关物质进行了量子化学(QC)计算。具有 E2Eâ²2 4câ6e(简称 BA)的构型是 13、15 和 16 的全局最小值,这再现了观察到的结构:BA 必须通过形成 E2Eâ²2 4câ6e 来稳定。具有双 n(S)â¯Ï*(SeâC) 3câ4e 相互作用的 14(AB)是全局最小值,这表明Ï*(SeâC) 在稳定 AB 中的 3câ4e 方面起着至关重要的作用。基于 QC 计算,考虑了 EâE 的新型反应性。