Stimulus-Responsive Supramolecular pKa Tuning of Cucurbit[7]uril Encapsulated Coumarin 6 Dye
Stimulus-Responsive Supramolecular pKa Tuning of Cucurbit[7]uril Encapsulated Coumarin 6 Dye
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DOI：
10.1021/jp212459r
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发表时间：
2012-03-29
影响因子：
3.3
通讯作者：
Bhasikuttan, Achikanath C.
中科院分区：
文献类型：
--
作者：
Barooah, Nilotpal;Mohanty, Jyotirmayee;Bhasikuttan, Achikanath C.
本文报道了香豆素6 （C6）染料与葫芦bbb_uril （CB7）大环相互作用后，宿主辅助客体质子化的有效机制。C6以1:1和2:1 （CB7/C6）的化学计量量吸收CB7大环，导致pK(a)大幅上升（从类似于0.8到6），并促进C6在正常pH条件下的质子化，具有重要的光化学意义。通过对温度变化或金属离子等刺激的反应，实现了组件的受控解离。通过这种方法，可以激活特定形式的客体，并为受控药物/染料的递送提供简单的刺激。此外，宿主辅助客体质子化提高了C6的稳定性和水溶性，是水基超分子染料激光系统的一个有前途的候选材料。这种简单的方案导致具有水溶性和生物相容性的光开关系统，原则上可以演变为在各种触发控制下递送和操作潜在功能分子组分的一般策略。
This article reports an efficient host-assisted guest protonation mechanism in coumarin 6 (C6) dye, upon its interaction with cucurbit[7]uril (CB7) macrocycle. C6 uptakes the CB7 macrocycle both in 1:1 and 2:1 (CB7/C6) stoichiometries, which brings out a large upward pK(a) shift (from similar to 0.8 to 6), and facilitates the protonation of C6 at normal pH conditions, having significant photochemical implications. Controlled dissociation of the assemblies has been achieved through their response to stimuli like temperature change or metal ions. By this approach, a specific form of the guest can be activated and could provide a simple stimulus for the controlled drug/dye delivery. Furthermore, the host-assisted guest protonation improves the stability and aqueous solubility of C6 and is a promising candidate for aqueous-based supramolecular dye laser system. Such simple protocol leading to photoswitchable systems having aqueous solubility and biocompatibility can in principle be evolved into a general strategy to deliver and operate potential functional molecular components under various trigger control.