Tracking Photoinduced Charge Separation in DNA: from Start to Finish,Accounts of Chemical Research

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Tracking Photoinduced Charge Separation in DNA: from Start to Finish
Accounts of Chemical Research ( IF 16.4 ) Pub Date : 2018-08-02 00:00:00 , DOI: 10.1021/acs.accounts.8b00090
Frederick D. Lewis ₁ , Ryan M. Young ₁ , Michael R. Wasielewski ₁

Affiliation

The initial studies of the dynamics of photoinduced charge separation conducted in our laboratories 20 years ago found strongly distance-dependent rate constants over short distances but failed to detect intermediates in the transport of positive charge (holes). These observations were consistent with the single-step superexchange or tunneling mechanism that had been observed for numerous donor–bridge–acceptor systems at that time. Subsequent studies found weak distance dependence for hole transport over longer distances in DNA, characteristic of incoherent hopping of either localized or delocalized holes. The introduction of synthetic DNA capped hairpin constructs possessing hole donor and acceptor chromophores (or purine bases) at opposite ends of a base-pair domain made it possible to determine the time required for transit of charge from one chromophore to the other and, in some cases, to distinguish between the transit time and the much faster initial charge injection time. These studies eliminated conventional tunneling as a viable mechanism for charge transport in DNA except at very short donor–acceptor separations; however, they did not establish the presence or nature of intermediates in the charge separation process.

中文翻译：

跟踪DNA中的光诱导电荷分离：从开始到完成

20年前在我们的实验室中进行的光诱导电荷分离动力学的初步研究发现，短距离内强烈依赖于距离的速率常数，但未能检测到正电荷（空穴）传输中的中间物。这些观察结果与当时在众多供体-桥-受体系统中观察到的单步超交换或隧穿机制是一致的。随后的研究发现，DNA中较长距离的空穴传输具有较弱的距离依赖性，这是局部或非局部空穴不相干跳跃的特征。在碱基对结构域的相对末端引入具有空穴供体和受体生色团（或嘌呤碱基）的合成DNA封盖的发夹构建体，可以确定电荷从一种生色团转移到另一种生色团所需的时间，并且在某些情况下在这种情况下，要区分渡越时间和更快的初始电荷注入时间。这些研究消除了传统的隧穿作为在DNA中进行电荷传输的可行机制，除非供体与受体的间隔很短。但是，他们没有确定电荷分离过程中中间体的存在或性质。这些研究消除了传统的隧穿作为在DNA中进行电荷传输的可行机制，除非供体与受体的间隔很短。但是，他们没有确定电荷分离过程中中间体的存在或性质。这些研究消除了传统的隧穿作为DNA中电荷传输的可行机制，除非供体与受体的间隔很短。但是，他们没有确定电荷分离过程中中间体的存在或性质。

更新日期：2018-08-02

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