Gigantic Magnetic Field Effect on the Long-Lived Intermolecular Charge-Separated State Created at the Nonionic Bilayer Membrane
Gigantic Magnetic Field Effect on the Long-Lived Intermolecular Charge-Separated State Created at the Nonionic Bilayer Membrane
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巨大磁场对非离子双层膜上产生的长寿命分子间电荷分离状态的影响
DOI：
10.1021/acs.jpcb.8b08389
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Ikoma Tadaaki
中科院分区：
文献类型：
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作者：
Miura Tomoaki;Maeda Kiminori;Oka Yoshimi;Ikoma Tadaaki
为了实现低成本的有机光子-能量转换，超分子方法作为精确合成共价连接的供体（D）-受体（A）分子的相反方法已经成为关注的焦点。本文报道了金属卟啉（D）和烷基紫精（A）在非离子表面活性剂和胆固醇分子自组装形成的囊泡膜界面上的长寿命（~ 3 μs）分子间电荷分离（CS）态的光生反应。逃逸自由基的产率低得可以忽略不计，如在共价连接的D-A系统中的CS状态的情况下。此外，在室温下施加250 mT的磁场后，CS态的瞬态浓度急剧增加了100%。对CS态自旋动力学的模拟表明，快速（~ 107 s-1）的自旋选择性复合和缓慢（105- 106 s-1）的解离-再相遇动力学是CS态长寿命和巨磁场效应的关键过程.事实证明，这种动力学是急剧依赖于温度和烷基链长度的紫精。目前的结果将导致未来材料的发展，用于光能转换，药物输送和微观生物探针。
For realization of low-cost organic photon-energy conversion, the supramolecular approach has been a focus of attention as a counter approach to precise synthesis of covalently linked donor (D)–acceptor (A) molecules. Here we report photogeneration of a long-lived (∼3 μs) intermolecular charge-separated (CS) state of metal porphyrins (D) and an alkyl viologen (A) at an interface of a vesicle membrane formed by self-assembly of nonionic surfactant and cholesterol molecules. The yield of escaped free radicals is negligibly low as in the case of CS states in covalently linked D–A systems. Furthermore, the transient concentration of the CS state dramatically increases by ∼100% upon application of a magnetic field of 250 mT at room temperature. The simulation of the spin dynamics of the CS state indicates that fast (∼107s–1) spin-selective recombination and slow (105–106s–1) dissociation–re-encounter dynamics are the key processes for the long CS-state lifetime and the gigantic magnetic field effect. It has turned out that such dynamics are sharply dependent on temperature and alkyl chain length of the viologen. The present results would lead to the development of future materials for light energy conversion, drug delivery, and microscopic bioprobes.