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

在这项由化学系化学结构、动态和机理B计划资助的项目中，加州大学河滨分校的瓦伦丁·武列夫教授正在开发新的合成系统，以研究偶极对电荷转移的影响。电荷转移是最基本的过程之一，对于管理能量流动和维持地球上的生命至关重要。呼吸作用、光合作用、电池、电子设备和生命的许多其他复杂组成部分在很大程度上依赖于有效的电荷转移过程。同时，电偶极子无处不在，它们周围的局域场可以对电荷的运动产生深远的影响。因此，重要的是要了解偶极如何影响电荷转移，以便在增强期望的正向电子传递的同时抑制不期望的过程。Vullev教授的团队处于有利地位，可以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。计划了有K-12学生参加的外联活动。将为高中生提供暑期研究培训，包括撰写科学论文和制作科学视频。更具体地说，这个项目的目标是探索偶极如何影响生物激发的分子驻极体中电荷转移系统中的电子耦合，分子驻极体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可以调制前线轨道的离域，改变施主-受主的电子耦合，导致电荷转移速率发生数量级的变化。它有三个具体目标：(1)确定管理偶极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的偶极效应；以及(3)确定径向离域对空穴跳跃动力学的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.