Nonequilibrium Dynamics of Proton-Coupled Electron Transfer in Proton Wires: Concerted but Asynchronous Mechanisms.
Nonequilibrium Dynamics of Proton-Coupled Electron Transfer in Proton Wires: Concerted but Asynchronous Mechanisms.
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DOI：
10.1021/acscentsci.0c00756
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发表时间：
2020-09-23
影响因子：
18.2
通讯作者：
Hammes-Schiffer S
中科院分区：
文献类型：
--
作者：
Goings JJ;Hammes-Schiffer S
电子和质子之间的耦合以及质子的长距离传输在整个生物学中起着重要的作用。衍生自苯并咪唑-苯酚（BIP）构建体的仿生系统已被设计为在电化学或光化学氧化后进行质子耦合电子转移（PCET）。此外，这些系统可以通过多质子PCET沿着氢键网络或质子线传输质子。本文采用第一性原理分子动力学方法研究了BIP分子中单质子和双质子氧化转移的非平衡动力学过程。虽然这些过程是协调一致的，没有观察到稳定的中间体，模拟预测，他们主要是异步的超快时间尺度。对于这两个系统，第一质子转移通常发生在电子转移后100 fs。对于双质子转移系统，通常第二质子转移发生在初始质子转移之后数百飞秒。使用机器学习算法来识别质子转移所必需的关键分子振动模式：主导整体内球重组的缓慢面内弯曲模式，导致振动相干性的质子供体-受体运动，以及更快的供体-氢拉伸模式。异步双质子转移机制可以理解为对应于两个质子相关的质子供体-受体运动的显著模式，通常一次仅减少一个供体-受体距离。虽然这些PCET过程出现协调的时间尺度上的典型的电化学实验，连接这些BIP结构的光敏剂，可以使检测的电子和多个质子转移的双极性与超快二维光谱。了解基本的PCET机制在这一水平将指导PCET系统的催化和能量转换过程的设计。神经网络有助于预测生物启发分子的重要运动，当它们经历质子耦合电子转移时，包括沿着质子线的一个或两个质子转移。
The coupling between electrons and protons and the long-range transport of protons play important roles throughout biology. Biomimetic systems derived from benzimidazole-phenol (BIP) constructs have been designed to undergo proton-coupled electron transfer (PCET) upon electrochemical or photochemical oxidation. Moreover, these systems can transport protons along hydrogen-bonded networks or proton wires through multiproton PCET. Herein, the nonequilibrium dynamics of both single and double proton transfer in BIP molecules initiated by oxidation are investigated with first-principles molecular dynamics simulations. Although these processes are concerted in that no thermodynamically stable intermediate is observed, the simulations predict that they are predominantly asynchronous on the ultrafast time scale. For both systems, the first proton transfer typically occurs ∼100 fs after electron transfer. For the double proton transfer system, typically the second proton transfer occurs hundreds of femtoseconds after the initial proton transfer. A machine learning algorithm was used to identify the key molecular vibrational modes essential for proton transfer: a slow, in-plane bending mode that dominates the overall inner-sphere reorganization, the proton donor–acceptor motion that leads to vibrational coherence, and the faster donor–hydrogen stretching mode. The asynchronous double proton transfer mechanism can be understood in terms of a significant mode corresponding to the two anticorrelated proton donor–acceptor motions, typically decreasing only one donor–acceptor distance at a time. Although these PCET processes appear concerted on the time scale of typical electrochemical experiments, attaching these BIP constructs to photosensitizers may enable the detection of the asynchronicity of the electron and multiple proton transfers with ultrafast two-dimensional spectroscopy. Understanding the fundamental PCET mechanisms at this level will guide the design of PCET systems for catalysis and energy conversion processes. Neural networks help predict important motions in bioinspired molecules when they undergo proton-coupled electron transfer comprising one or two proton transfers along a proton wire.
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影响因子：
62.1
作者：
Dempsey, Jillian L.;Winkler, Jay R.;Gray, Harry B.
通讯作者：
Gray, Harry B.
DOI：
10.1073/pnas.0708967105
发表时间：
2008-06-17
影响因子：
11.1
作者：
Markle, Todd F.;Rhile, Ian J.;Mayer, James M.
通讯作者：
Mayer, James M.
影响因子：
4.4
作者：
BECKE, AD
通讯作者：
BECKE, AD
影响因子：
3.3
作者：
Ghosh, Ipsita;Khan, Sahr;BrudviG, Gary W.
通讯作者：
BrudviG, Gary W.
DOI：
10.1073/pnas.84.20.7099
发表时间：
1987-10-01
影响因子：
11.1
作者：
BARRY, BA;BABCOCK, GT
通讯作者：
BABCOCK, GT