Photoresponsive Vinyl Azide Crystals

在这个由化学学部化学结构、动力学和机理B项目资助的项目中，辛辛那提大学化学系的Anna D. Gudmundsdottir教授正在研究“光动力”晶体背后的基础科学。这些不寻常的物质在光照下会移动。在光照下，光动力晶体可以扭曲、弯曲、跳跃、爬行或破碎。这种行为为光转化为运动的新设备的开发提供了潜力，例如致动器和传感器。该项目结合了光化学和材料科学的跨学科性质，为学生提供了多样化的教育培训机会。通过这项研究，学生将成为未来的科学家，能够解决社会面临的技术挑战。高中和大学本科生都将从科学界代表性不足的群体中招募，在Gudmundsdottir实验室进行研究。学生也将被提供以专业发展为重点的教育活动。Gudmundsdottir研究小组研究了结晶乙烯基叠氮化物衍生物的光动力学行为，这些衍生物在光照下解离成三态乙烯基亚硝基和分子N2。氮在晶格内的释放模式对每个叠氮化物衍生物都是独特的。有些晶体在破裂之前可以容忍晶格内大量氮气气泡的积聚，而另一些则在光照下立即释放氮气。在本研究中，确定了控制晶体内N2分子释放的结构因素。作为本研究的一部分，通过对纳米晶体进行激光闪光光解，研究了这些化合物的固态光反应性。这些研究的目的是表征晶体内形成的瞬态，并确定这些瞬态的固态动力学。x射线晶体学和光产物鉴定是本研究的关键要素。量子化学计算支持固态反应机制。总的来说，这些数据使阐明详细的固态反应机制成为可能，并解释了晶格如何控制乙烯基叠氮化物衍生物的反应性和光动力学行为。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, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Anna D. Gudmundsdottir of the Department of Chemistry at the University of Cincinnati is studying the fundamental science behind "photodynamic" crystals. These are unusual substances which move as they are exposed to light. When illuminated, photodynamic crystals can twist, bend, leap, crawl or shatter. This behavior holds the potential for development of new devices in which light is converted into motion, such as actuators and sensors. The interdisciplinary nature of this project, which connects photochemistry and materials science, provides diverse educational training opportunities for students. Through this research, students are prepared as future scientists who can address the technical challenges facing society. Both high school and college undergraduate students will be recruited from groups underrepresented in science to carry out research in the Gudmundsdottir laboratory. Students will also be provided with educational activities that focus on their professional development.The Gudmundsdottir research group investigates photodynamic behavior of crystalline vinyl azide derivatives which, upon light exposure, dissociate to triplet vinylnitrenes and molecular N2. The mode of nitrogen release within the crystal lattice is distinctive for each vinyl azide derivative. Some crystals tolerate a build-up of large N2 bubbles within the lattice before cracking, whereas others release N2 immediately with light exposure. In this research, structural factors which control the release of N2 molecules within the crystal are identified. As part of this research, solid-state photoreactivity of these compounds is investigated by performing laser flash photolysis of nanocrystals. These studies are designed to characterize the transients formed within the crystals and determine the solid-state kinetics of these transients. X-ray crystallography and photoproduct identification are critical elements of this study. Solid-state reaction mechanisms are supported by quantum chemical calculations. Collectively, these data make it possible to elucidate detailed solid-state reaction mechanisms and explain how the crystal lattice controls both the reactivity and the photodynamic behavior of vinyl azide derivatives.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.