Mechanistic and Exploratory Photochemistry with Plane-Polarized Light

在化学系化学结构、动力学和机理-B（CSDM-B）项目的支持下，北方伊利诺伊大学的Evgueni Nesterov教授将研究一种通过使用定向介质和平面偏振光来控制光化学反应选择性的新方法。光化学本质上是“绿色化学”，因为它使用光（可能是太阳光）作为能源和反应物。光化学的研究计划旨在建立一个新的范式，用于控制和提高光化学反应的选择性，并可能导致新的环境友好的化学过程。它还将导致更好地了解光化学反应的机制，从而有助于将其开发为实际有用的合成工具。参加该计划的学生将受益于多学科和协作培训。Nesterov小组还将通过参与当地K-12学校的特别实践推广活动为社会做出贡献。这项研究的目标是建立和发展一种与平面偏振光光化学调谐有关的新范式。 这有可能通过光反应性化合物的均匀分子排列和通过使用平面偏振光对特定电子跃迁的空间选择性激发来控制光化学反应的过程和选择性。与以前通过对光反应分子施加某些几何约束来控制光化学反应性的方法相比，所提出的方法将不依赖于拓扑化学“反应腔”。相反，这里采取的方法是选择性地激发特定的电子跃迁，导致所需的光化学转化。如果成功的话，这些研究还将提供一种简单的方法，通过实验将光化学反应的结果与特定的电子跃迁相关联，这是研究光化学反应机制的一个潜在的有价值的工具。该项目的具体目标包括：（1）设计和合成一系列具有增强的液晶取向能力的光化学反应性化合物，使这些系统显示出激发选择性的光化学反应性;（2）使用平面偏振光详细研究这些系统的光化学;（3）研究在没有特别添加的配向基团的情况下在光化学基底上进行类似反应的潜力，和（4）开发用于在不使用液晶溶剂的情况下均匀配向光反应性分子的替代方法。 这将包括检查朗缪尔薄膜的空气-水界面或使用分子“排列增强剂”和研究平面偏振光控制的光化学在这样的系统。这个奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

With support from the Chemical Structure, Dynamics, and Mechanisms-B (CSDM-B) program of the Chemistry Division, Professor Evgueni Nesterov of Northern Illinois University will investigate a novel method to control selectivity of photochemical reactions through the use of aligning media and plane-polarized light. Photochemistry is intrinsically “green chemistry” as it uses light (potentially solar light) as both source of energy and reactant. The proposed research program in photochemistry aims to establish a new paradigm for controlling and enhancing selectivity of photochemical reactions, and can potentially lead to new environmentally benign chemical processes. It will also lead to better understanding of the mechanisms of photochemical reactions, thus helping to develop them as practically useful synthetic tools. Students participating in this program will benefit from multidisciplinary and collaborative training. The Nesterov group will also contribute to society through participation in special hands-on outreach activities to local K-12 schools.The goal of this research is to establish and develop a novel paradigm relating to the tuning of photochemistry with plane-polarized light. This has the potential to control the course and selectivity of photochemical reactions through the uniform molecular alignment of photoreactive compounds and through the use of spatially selective excitation of a particular electronic transition with plane-polarized light. In contrast to previous ways of controlling photochemical reactivity through imposing certain geometric constraints on the photoreactive molecule, the proposed approach will not rely on a topochemical “reaction cavity.” Rather the approach taken here is to selectively excite a particular electronic transition leading to a desired photochemical transformation. If successful, these studies would also deliver a simple method to experimentally correlate the outcome of a photochemical reaction with specific electronic transitions, a potentially valuable tool for the study of photochemical reaction mechanisms. The project involves the following specific aims: (1) design and synthesis of a series of photochemically reactive compounds with enhanced ability to align in liquid crystalline media, allowing these systems to display excitation-selective photochemical reactivity; (2) detailed investigation of the photochemistry of these systems using plane-polarized light; (3) investigation of the potential to carry out similar reactions on photochemical substrates without specially added aligning groups and (4) development of alternative methods for the uniform alignment of photoreactive molecules without using a liquid crystalline solvent. This will include examining Langmuir films on air-water interfaces or using molecular “alignment enhancers” and studying plane-polarized light controlled photochemistry in such systems.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.