Physical and Photophysical Properties of Spin-Polarized Molecules

化学结构、动力学和机理 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，可以在多大程度上利用这种联系来操纵分子系统的化学反应性。模型的成功开发首次实现了偶极能量转移自旋控制的实验演示，在此基础上，正在开展的具体项目包括：(1) 详细阐述该模型，以确定其在福斯特理论方面的适用性限制；(2) 扩展该模型以交换能量转移（即 Dexter）；(3) 零场自旋极化对自旋耦合过渡金属团簇中光致电子转移过程的影响；(4) 合成和表征自旋耦合金属-半醌络合物分子，其中合成设计和理论的结合用于操纵分子内自旋极化。在所有这些项目中，研究都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）以及包括密度泛函理论计算在内的理论工作来进行，以探索将自旋和自旋极化纳入现有理论以描述电子和能量转移动力学。支持这项研究的概念代表了有关光致特性的新研究领域。分子的结构：该项目将为一类巨大化合物的电子结构的一个方面提供重要的见解，而目前这些化合物的实验信息很少。具有独特自旋（电子角动量）和/或磁特性的化合物，特别是那些可以以可预测的方式合成操纵特性的化合物，有望成为基于分子的电子材料的基础。通过这项工作获得的知识可以为用于信息存储、能量转换和催化的下一代电子和光电器件的分子系统的合理设计提供基础。参与这项工作的个人，包括本科生和研究生水平的男性和女性，正在接受合成化学、最先进的光谱方法、分子系统磁性研究以及先进理论方法方面的广泛培训。

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.