Benzene Triimide Cage as a Selective Container of Azide
Benzene Triimide Cage as a Selective Container of Azide
复制标题
苯三酰亚胺笼作为叠氮化物的选择性容器
DOI：
10.1021/acs.orglett.9b02782
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发表时间：
2019
期刊：
影响因子：
5.2
通讯作者：
Wang De-Xian
中科院分区：
文献类型：
--
作者：
Tuo De-Hui;Ao Yu-Fei;Wang Qi-Qiang;Wang De-Xian
苯三酰亚胺（BTI，或苯三酰亚胺）是一种 C3 对称主链，具有高度缺电子、扩展的 π 表面和三个易于官能化的位点。在这里，我们报告了第一个基于 BTI 的笼子，由两个面对面的 BTI 组成，由三间二甲苯间隔基支撑，并通过阴离子-π 相互作用有效、选择性地结合叠氮化物。该笼很容易由苯三酰亚胺分两步合成。晶体结构表明，两个 BTI 平面可以以约 5-6 Å 分开，并形成明确的缺电子腔。在一系列测试的阴离子中，发现笼能够结合 N3-、SCN- 和 I-。特别是，与 N3– 的结合非常强（Ka= 11098 ± 46 M–1）且具有高度选择性，分别比 SCN– 和 I– 高 150 倍和 250 倍。然而，对照单一 BTI 仅显示出非常弱的结合（Ka<5 M–1）。晶体结构表明，N3-通过多个非常短的阴离子-π相互作用被紧紧地捕获在空腔内。在 NMR 中观察到 N3 从空腔中缓慢进入-释放。还讨论了相互作用的电荷转移和电子转移特征。
Benzene triimide (BTI, or mellitic triimide) is aC3-symmetric backbone with a highly electron-deficient, extended π surface and three easy functionalization sites. Here, we report the first BTI-based cage composed of two face-to-face BTIs pillared by threem-xylylene spacers and efficient and selective binding of azide through cooperative anion−π interactions. The cage was easily synthesized in two steps from benzene triimide. Crystal structures showed that the two BTI planes can be separated at about 5–6 Å and form a well-defined electron-deficient cavity. Among a series of anions tested, the cage was found able to bind N3–, SCN–, and I–. In particular, the binding toward N3–is very strong (Ka= 11098 ± 46 M–1) and highly selective, over 150 and 250 times higher than SCN–and I–, respectively. The control single BTI, however, showed only very weak binding (Ka<5 M–1). The crystal structure showed that N3–is tightly trapped within the cavity through multiple, very short anion−π interactions. The slow enter–release of N3–from the cavity was observed in the NMR. The charge-transfer and electron-transfer character of the interactions was also discussed.