Supramolecular control during triplet sensitized geometric isomerization of stilbenes encapsulated in a water soluble organic capsule
Supramolecular control during triplet sensitized geometric isomerization of stilbenes encapsulated in a water soluble organic capsule
复制标题
水溶性有机胶囊中二苯乙烯三重态敏化几何异构化过程中的超分子控制
DOI：
10.1039/c2pp25115a
复制
发表时间：
2012
影响因子：
3.1
通讯作者：
Vaidhyanathan Ramamurthy
中科院分区：
文献类型：
--
作者：
Shampa R. Samanta;Anand Parthasarathy;Vaidhyanathan Ramamurthy
研究了水溶性有机胶囊中几种二苯乙烯类化合物的三重态敏化光致异构化反应。在这项研究中，辛酸在疏水客体分子存在下自组装形成主客体络合物，用于在水中增溶疏水二苯乙烯和三重态增敏剂，并在所含烯烃的几何异构化过程中提供限制。通过监测4，4‘-二甲基苯在二苯乙烯及其氮类似物(二苯乙烯和双吡啶)存在下的稳态和时间分辨的室温磷光，我们已经能够确定包封的供体和包封的(或游离的)受体之间发生了三重-三重能量转移。能量传递过程的机制尚未完全了解，尽管在早期的文献中也曾报道过类似的现象，其中Cram的半碳酸酯是宿主。油酸胶囊内顺式和反式异构体的光稳定状态组成取决于两种异构体与油酸胶囊的相对结合强度。需要进一步的研究，以充分利用这里所做的有趣的观察，将光异构化转向单一的异构体。
Triplet sensitized photoisomerization of several stilbenes included within a water-soluble organic capsule has been investigated. In this study octa acid that self assembles in the presence of hydrophobic guest molecules to form a host-guest complex is utilized to solubilize hydrophobic stilbenes and triplet sensitizers in water, and to provide confinement during the geometric isomerization of included olefins. By monitoring the steady state and time resolved room temperature phosphorescence from 4,4′-dimethylbenzil in the presence of acceptor stilbenes and their nitrogen analogues (stilbazole and bispyridyl ethylene) we have been able to establish that triplet-triplet energy transfer occurs between encapsulated donors and encapsulated (or free) acceptors. The mechanism of the energy transfer process is yet to be fully understood although a similar phenomenon has been reported earlier in the literature with Cram’s hemicarcerand as the host. The photostationary state composition of cis and trans isomers within the OA capsule is dependent on the relative binding strength of the two isomers with the OA capsule. Further investigation is needed to fully exploit the interesting observations made here to steer the photoisomerization towards a single isomer.