Low-temperature m atrix isolation method is the most popular one to generate and store reactive molecules and characterize them by in situ IR spectroscopy. Recognizing the need for a simpler method to trap and store such molecules and characterize by NMR spectroscopy at room temperature in solution, we have performed experiments exploring the value of water-soluble octa acid (OA) capsule as a storage vessel. The molecule we have chosen to illustrate the feasibility is the highly hindered 7-cis-β-ionone, which has been established to exist in equilibrium with its cyclic form with the later favored at room temperature. In this study, we have shown that confined space can be an alternative to temperature to tilt an equilibrium toward higher energy isomer. During the course of the study, we were surprised to note that 7-trans-β-ionone aggregates in water and has distinct ¹H NMR spectra. Ability to assemble characterizable organic aggregates in water reveals the value of water as a reaction medium that is yet to be fully explored by photochemists. Finally, we have clarified the likely mechanism of secondary photoreaction of α-pyran to the final photoproduct that involves 1,5-hydrogen migration.

中文翻译：

---

有机胶囊作为基质，可在室温下在水溶液中捕获和储存反应性分子：7-cis-β-Ionone†

低温基质分离方法是最流行的一种生成和存储反应性分子并通过原位红外光谱对其进行表征的方法。认识到需要一种更简单的方法来捕获和储存这些分子，并在室温下通过 NMR 光谱在溶液中进行表征，我们进行了实验，探索水溶性八酸 (OA) 胶囊作为储存容器的价值。我们选择用来说明可行性的分子是高度受阻的 7-顺式-β-紫罗兰酮，已确定与其环状形式平衡存在，后者在室温下更受青睐。在这项研究中，我们已经表明，密闭空间可以替代温度，以使平衡向更高能量的异构体倾斜。在研究过程中，我们惊讶地发现 7-反式-β-紫罗兰酮在水中聚集并具有不同的¹ H NMR 光谱。在水中组装可表征的有机聚集体的能力揭示了水作为反应介质的价值，光化学家尚未充分探索。最后，我们阐明了 α-吡喃二次光反应生成最终光产物的可能机制，其中涉及 1,5-氢迁移。