Physical and Photophysical Properties of Spin-Polarized Molecules

化学结构、动力学和机制B项目支持密歇根州立大学化学系的James K. McCusker教授设计和开发化学系统，旨在确定分子的物理和/或光物理性质与其固有自旋性质之间是否存在因果关系，如果存在，为了操纵分子系统的化学反应性，这种联系可以被利用到什么程度。在成功开发了一个模型的基础上，该模型导致了对偶极能量转移的自旋控制的首次实验演示，目前正在进行的具体项目是(1)详细阐述该模型，以确定其在Förster理论中的适用性限制，(2)将该模型扩展到交换能量转移（即Dexter），(3)零场自旋极化对自旋耦合过渡金属团簇中光诱导电子转移过程的影响，(4)自旋耦合金属-半醌配合物分子的合成和表征，其中利用合成设计和理论相结合的方法来控制分子内的自旋极化。在所有这些项目中，研究是通过有机和无机合成化学、稳态和时间分辨光谱测量（包括但不限于）发射、超快时间分辨吸收和电子顺磁共振的融合来进行的。以及理论方面的努力，包括密度泛函理论计算，探索将自旋和自旋极化纳入现有理论，以描述电子和能量传递动力学。支撑这项研究的概念代表了一个关于分子光诱导特性研究的新领域：该项目将为目前几乎没有实验信息的大量化合物的电子结构的一个方面提供重要见解。具有独特自旋（电子角动量）和/或磁性质的化合物，特别是那些可以以可预测的方式合成操纵的化合物，有望成为分子基电子材料的基础。通过这项工作获得的知识可以为下一代电子和光电子设备的分子系统的合理设计提供基础，用于信息存储，能量转换和催化。参与这项工作的个人，包括男女本科生和研究生，正在接受合成化学、最先进的光谱学方法、分子系统磁性研究以及先进理论方法方面的广泛训练。

The Chemical Structure, Dynamics and Mechanisms B Program supports Professor James K. McCusker of the Department of Chemistry at Michigan State University for the design and development of chemical systems geared toward determining whether there exists a cause-and-effect relationship between the physical and/or photophysical properties of molecules and their innate spin properties, and if so, to what extent that connection can be exploited in order to manipulate the chemical reactivity of molecular systems. Building on the successful development of a model that led to the first experimental demonstration of spin control of dipolar energy transfer, specific projects being pursued are (1) elaboration of this model to determine the limits of its applicability with regard to Förster theory, (2) extension of this model to exchange energy transfer (i.e., Dexter), (3) the influence of zero-field spin polarization on photo-induced electron transfer processes in spin-coupled transition metal clusters, and (4) the synthesis and characterization of spin-coupled metal-semiquinone complexes molecules in which a combination of synthetic design and theory is being used to manipulate intramolecular spin polarization. In all of these projects, the research is being carried out through a confluence of organic and inorganic synthetic chemistries, steady-state and time-resolved spectroscopic measurements including (but not limited to) emission, ultrafast time-resolved absorption, and electron paramagnetic resonance, as well as theoretical efforts that include density functional theory calculations to explore the incorporation of spin and spin polarization into existing theories to describe electron and energy transfer dynamics.The concepts underpinning this research represent a new area of study concerning the light-induced properties of molecules: this project will provide important insights into an aspect of the electronic structure of an enormous class of compounds for which there is little experimental information presently available. Compounds possessing unique spin (angular momentum of electrons) and/or magnetic properties, particularly those whose properties can be manipulated synthetically in a predictable manner, hold promise as the basis for molecular-based electronic materials. The knowledge gained through this work can provide a foundation for the rational design of molecular systems for next-generation electronic and photo-electronic devices for information storage, energy conversion, and catalysis. The individuals involved in this work, which include men and women at both the undergraduate and graduate level, are receiving broad-based training in synthetic chemistry, state-of-the-art spectroscopic methodology, the study of the magnetic properties of molecular systems, as well as advanced theoretical methods.