Ultrafast Electron Transfer in Supramolecular Mixed Valence Complexes

该奖项授予加州大学圣地亚哥分校的Kubiak教授，由化学系的大分子，超分子和纳米化学项目资助，重点是超快化学反应;那些在万亿分之一秒（1皮秒）内发生的大型超分子结构。 这些反应涉及电子在合理的长距离上的转移，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较弱的相互作用的强度;以及（2）观察到混合价纳米团簇。后者是由钌簇组成的复杂分子结构，其通过附着的金属和半导体纳米颗粒转移电荷。该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响应不同类型的途径。 由于能够轻松地综合操纵这些复杂系统的化学成分，Kubiak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，研究人员首先通过增加弱相互作用（如氢键）的强度来稳定复合物，然后通过为此目的设计的光谱方法分析这些新稳定的复合物中的超快电子转移特性。 这项研究与科学和工程界都有关，他们寻求开发新一代的分子电子器件。 这种器件的未来取决于具有两种或更多种稳定状态的分子复合物的发展，这些分子复合物可以在这些状态之间以极快的反应时间切换。

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.