Long-range dynamics in the photoexcited states of rigidly linked composite molecular systems

阐明远程动力学机制不仅对理解自然系统中的能量和电子转移是必不可少的，而且对于设计有效地收集光和产生长寿命的电荷分离物质的系统也是必不可少的。虽然超交换机制在远距离相互作用中的作用受到了广泛的关注，但大多数研究都是在线性连接的分子系统上进行的。在这项工作中，我们研究了，i)一系列铜（II）通过芳香间隔剂连接的无卟啉基卟啉二聚体的系统间交叉过程；II)锌（II）线性或非线性桥连接的无卟啉基卟啉二聚体的远程单重线-单重线能量传递。讨论了刚性连接给体-桥体-受体分子体系中超交换介导的激发动力学的间隔依赖，发现桥体部分的分子轨道起着重要作用。

Elucidation of the mechanisms for long-range dynamics is indispensable not only in understanding energy and electron transfer occurs in natural systems but also in designing systems that efficiently harvest light and generate long-lived charge-separated species. While much attention has been paid to the role of the superexchange mechanism in long-range interaction, most of studies have been carried out on linearly-linked molecular systems. In this work, we have studied, i) enhanced intersystem crossing process in a series of copper(II) porphyrin - free base porphyrin dimers linked via an aromatic spacer and ii) long-range singlet-singlet energy transfer of zinc(II) porphyrin - free base porphyrin dimers, which are linked linear or non-linear bridges. Spacer dependence of superexchange mediated excited-dynamics was discussed in rigidly linked donor-bridge-acceptor molecular systems, and it was found that molecular orbitals in the bridge part take an important role.