Marcus Relationship Maintained During Ultrafast Electron Transfer Across a Supramolecular Capsular Wall
Marcus Relationship Maintained During Ultrafast Electron Transfer Across a Supramolecular Capsular Wall
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在超分子囊壁超快电子转移过程中保持马库斯关系
DOI：
10.1021/acs.jpca.0c03944
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Ramamurthy, V.
中科院分区：
文献类型：
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作者：
Das, Aritra;Kamatham, Nareshbabu;Mohan Raj, A.;Sen, Pratik;Ramamurthy, V.
通过有机荚膜壁在激发态供体和基态受体之间进行光致电子转移，其速率常数在0.32-4.0 × 1011s-1in水溶液中变化。供体被包裹在阴离子的超分子包膜宿主内，阳离子受体通过库仑引力与供体保持更近的距离。这样的安排导致电子转移过程没有扩散。反应的自由能（ΔG°）和电子转移速率与反转呈马库斯关系。从图中，λ和vele分别为1.918和0.0058 eV。鉴于供体保持在非极性无溶剂的密闭空间内，并且受体周围的环境没有太大变化，观察到的λ被认为是由于“内部”重组而不是“溶剂”重组。本文研究的荚膜组装与低温下介质为刚性的玻璃和晶体之间存在相似之处。估计的电子耦合（Vel）表明通过囊壁存在供体和受体之间的相互作用。1h NMR谱也证实了这种相互作用的存在。这项研究的结果表明，存在于密闭空间内的分子可以从外部被激活。这为探索有机胶囊内自由基离子的反应性和动力学提供了一个机会。
Photoinduced electron transfer across an organic capsular wall between excited donors and ground-state acceptors is established to occur with rate constants varying in the range 0.32–4.0 × 1011s–1in aqueous buffer solution. The donor is encapsulated within an anionic supramolecular capsular host, and the cationic acceptor remains closer to the donor separated by the organic frame through Coulombic attraction. Such an arrangement results in electron transfer proceeding without diffusion. Free energy of the reaction (ΔG°) and the rate of electron transfer show Marcus relation with inversion. From the plot, λ andVelwere estimated to be 1.918 and 0.0058 eV, respectively. Given that the donor remains within the nonpolar solvent-free confined space, and there is not much change in the environment around the acceptor, the observed λ is believed to be because of “internal” reorganization rather than “solvent” reorganization. A similarity exists between the capsular assembly investigated here and glass and crystals at low temperature where the medium is rigid. The estimated electronic coupling (Vel) implies the existence of interaction between the donor and the acceptor through the capsular wall. Existence of such an interaction is also suggested by1H NMR spectra. Results of this study suggest that molecules present within a confined space could be activated from outside. This provides an opportunity to probe the reactivity and dynamics of radical ions within an organic capsule.