Mechanistic Studies of Dipole Effects on Electronic Coupling in Charge Transfer Implemented as Photoinduced Dynamics of Intramolecular Hole Hopping

在这个由化学部化学结构、动态和机制B项目资助的项目中，加州大学河滨分校的Valentine Vullev教授正在开发新型合成体系，以研究偶极子对电荷转移的影响。电荷转移是最基本的过程之一，对管理能量流和维持地球上的生命至关重要。呼吸作用、光合作用、电池、电子设备和许多其他复杂的生命组成部分都严重依赖于有效的电荷转移过程。同时，电偶极子到处都是，它们周围的局部场对电荷的运动有深远的影响。因此，了解偶极子如何影响电荷转移是很重要的，以便在抑制不需要的过程的同时增强所需的正向电子转导。Vullev教授的团队有能力为学生提供最高水平的教育和培训，包括那些在科学领域代表性不足的学生。计划开展包括K-12学生在内的推广活动。将为高中生提供包括撰写科学论文和制作科学视频在内的暑期研究训练。更具体地说，这个项目的目标是探索偶极子如何影响生物激发分子驻极体中电荷转移系统中的电子耦合，这是具有有序电偶极矩的系统。这项研究是基于Vullev教授的发现，即分子驻极体的偶极子可以调节前沿轨道的离域和改变供体-受体电子耦合，导致电荷转移速率的数量级变化。它有三个具体目标：(1)确定控制偶极子调制电子耦合的参数；(2)确定通过空穴跳跃和隧道机制发生的电荷转移中的偶极子效应；(3)确定自由基离域对跳空穴动力学的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Valentine Vullev at the University of California, Riverside is developing new classes of synthetic systems to study the influence of dipoles on charge transfer. Charge transfer is among the most fundamental processes, essential for managing energy flow and sustaining life on Earth. Respiration, photosynthesis, batteries, electronic devices and many other intricate components of lives heavily rely on efficient charge-transfer processes. Concurrently, electric dipoles are everywhere, and the localized fields around them can have a profound effect on how charges move. Therefore, it is important to understand how dipoles affect charge transfer, in order to enhance desired forward electron transduction while suppressing undesired processes. Professor Vullev's group is well positioned to provide the highest level of education and training for students, including those underrepresented in science. Outreach activities involving K-12 students are planned. Summer research training, which includes writing scientific papers and producing scientific videos, will be provided for high school students. More specifically, the goal of this project is to explore how dipoles affect electronic coupling in charge-transfer systems in bioinspired molecular electrets, which are systems with ordered electric dipole moments. The research is based on Professor Vullev's discovery that the dipoles of molecular electrets can modulate the delocalization of frontier orbitals and alter donor-acceptor electronic coupling, leading to orders of magnitude changes in the charge-transfer rates. It has three specific aims: (1) determining parameters that govern dipole-modulated electronic coupling; (2) determining the dipole effects on charge transfer occurring via hole-hopping vs. tunneling mechanisms; and (3) determining the effect of radical delocalization on the dynamics of hole hopping.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.