EAGER: Controlling Photochemistry via Spatially Selective Excitation

在这个由化学部化学结构、动力学和机理-B（CSDM-B）项目资助的项目中，北方伊利诺伊大学的Evgueni Nesterov教授研究了一种新的一般原理，通过使用液晶介质和平面偏振光来控制光化学反应。液晶（LC）具有介于常规液体（因为它们可以流动）和固体晶体（因为它们以非常特定的方式取向）之间的特性。液晶显示器被广泛使用-一个例子是在数字表盘。 这项研究试图利用液晶来捕获光，并将光的能量均匀地重新定向到特定的化学反应中。该项目的风险很高，因为这一概念尚未在实践中得到证明。 如果成功的话，这项研究可能会建立一个新的模式，控制光化学反应，使非常具体的化学产品。这可能会导致新的环境友好的化学过程，依赖于光作为能源的化学转化。 参加该计划的学生受益于多学科和协作培训，使他们在技术就业市场上具有高度竞争力。他们还通过参与针对当地K-12教育的特别实践活动来为社会做出贡献。这个早期探索计划的最终目标是开发和实验确认一种新的范例，通过液晶（LC）中光反应化合物的均匀分子排列来控制光化学反应的过程和选择性介质和空间选择性激发特定的电子跃迁与平面偏振光。与通过对光反应性分子施加几何限制来控制光化学选择性的常规方式相反，这种方法依赖于特定电子跃迁的选择性激发，从而导致期望的光化学转化。该研究旨在设计和合成一系列具有增强的在CDLC介质中排列能力的光化学反应性化合物，其可以显示激发选择性光化学反应性。 该研究小组提供了详细的实验分析和表征，他们的LC强加的对齐和过渡偶极矩取向使用紫外/维斯偏振光谱。本研究为控制和提高光化学反应的选择性提供了一种新的思路。这可能会导致新的环境友好的化学过程，依赖于光作为能源的化学转化。除了这些实际利益，这项工作的更广泛的影响包括对STEM学科学生的多学科培训对社会的好处，无论是通过学生参与先进的研究，还是通过参加旨在提高公众对现代科学和技术的认识和欣赏的特别外联活动，该奖项反映了NSF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, Dynamics, and Mechanisms-B (CSDM-B) Program of the Chemistry Division, Professor Evgueni Nesterov of Northern Illinois University investigates a new general principle to control photochemical reactions through the use of liquid crystalline media and plane polarized light. Liquid crystals (LCs) have properties between those of conventional liquids (in that they can flow) and those of solid crystals (in that they are oriented in a very specific way). Liquid crystal displays are widely used - one example is in digital watch faces. This research seeks to use liquid crystals in capturing light and specifically and uniformly redirecting the light's energy into specific chemical reactions. The project is high risk as such a concept has not yet been demonstrated in practice. If successful, this research may establish a new paradigm for controlling photochemical reactions so that very specific chemical products are made. This can potentially lead to new environmentally benign chemical processes which rely on light as a source of energy for chemical transformations. Students participating in this program benefit from multidisciplinary and collaborative training, which allows them to become highly competitive in the technical job market. They also contribute to society through participation in special hands-on activities targeting local K-12 education.The ultimate goal of this early-stage exploratory program is to develop and experimentally confirm a novel paradigm for controlling the course and selectivity of photochemical reactions through the uniform molecular alignment of photoreactive compounds in liquid crystalline (LC) media and spatially selective excitation of specific electronic transitions with plane-polarized light. In contrast to the conventional ways of controlling photochemical selectivity by imposing geometrical restrictions on the photoreactive molecule, this approach relies on selective excitation of the particular electronic transitions leading to a desired photochemical transformation. The research seeks to design and synthesize a series of photochemically reactive compounds with enhanced ability to align in nematic LC media, which can display excitation-selective photochemical reactivity. The research group provides detailed experimental analysis and characterization of their LC-imposed alignment and transition dipole moment orientation using UV/vis polarization spectroscopy. This research program may establish a new paradigm for controlling and enhancing selectivity of photochemical reactions. This can potentially lead to new environmentally benign chemical processes which rely on light as a source of energy for chemical transformations. In addition to these practical benefits, the broader impacts of this work include benefits to the society from multidisciplinary training of students in STEM disciplines, both through student involvement in advanced research and participation in special outreach activities developed with the goal of improving public awareness and appreciation of modern science and technology, particularly among younger generations.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.