Ultrafast Electron Transfer in Supramolecular Mixed Valence Complexes

这一奖项授予加州大学圣地亚哥分校的库比亚克教授，由化学系的高分子、超分子和纳米化学项目资助，重点是超快化学反应；那些在大型超分子结构上发生的万亿分之一秒(1皮秒)的化学反应。这些反应涉及电子在相当长的距离上的转移，从1到4纳米。该项目建立在(1)观察到通过氢键交换电子可以增加通常弱相互作用的强度的基础上；(2)观察到混合价纳米团簇。后者是由Ru团簇组成的复杂分子结构，通过附着的金属和半导体纳米粒子传递电荷。这项研究将扩展到更复杂的系统，以阐明电子和电子转移速率如何通过新的超分子材料对不同类型的路径做出响应。鉴于能够轻松地综合操纵这些复杂系统的化学成分，库比亚克教授和他的团队能够为各种应用定制设计这些组件。为了探索这些复杂的结构，研究人员首先旨在通过增加它们的弱相互作用(如氢键)的强度来稳定这些化合物，然后通过为此目的设计的光谱方法分析这些新稳定的化合物中的超快电子转移性质。这项研究与科学界和工程界开发新一代分子电子设备的努力有关。这类器件的未来取决于具有两个或更多稳定状态的分子络合物的发展，这些分子络合物可以在这些状态之间切换，反应时间非常快。

This award to Professor Kubiak of the University of California, San Diego funded by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry focuses on ultrafast chemical reactions; those that occur in one-trillionth of a second (1 picosecond) over large supramolecular structures. These reactions involve the transfer of electrons over reasonably long distances, from 1 to 4 nanometers. The project builds on (1) the observation that exchanging electrons across hydrogen bonds can increase the strength of typically weak interactions; and (2) the observation of mixed valence nanoclusters. The latter are complex molecular structures composed of ruthenium clusters which transfer charge through attached metallic and semiconducting nanoparticles. The research will be extended to more complex systems in order to elucidate how electrons and electron transfer rates respond to different types of pathways through new supramolecular materials. Given the ability to easily manipulate the chemical compositions of these complex systems synthetically, Professor Kubiak and his team are able to custom design these assemblies for a variety of applications. In order to explore these intricate structures, the researchers first aim to stabilize the complexes by increasing the strength of their weak interactions (such as hydrogen bonds) and to then analyze the ultrafast electron transfer properties in these newly stabilized complexes via spectroscopic methods designed for this purpose. The research is relevant to both the scientific and engineering communities in their quest to develop new generations of molecular electronic devices. The future of such devices is dependent on the development of molecular complexes with two or more stable states, which can be switched between these states with extremely fast reaction times.