UV-Triggered Photodynamic Behavior of Azidostilbenes

Abstract

By Margaret Milbrandt, Biochemistry

Advisor: Anna Gudmundsdottir

Awards: Capstone Competition: Competitor

Presentation ID: 9

Abstract: There is a significant need for smart materials able to transduce light into mechanical motions because they can be used in applications such as biomedicine and soft robotics. Research in our group is focused on photodynamic crystals that acquire momentum by releasing gas, a mechanism that is similar to jet engines. The following will report the photodynamic behavior of azidostilbene derivatives that release nitrogen gas upon exposure to UV light. Different azidostilbene derivatives display different dynamic behavior. Some crack fiercely upon exposure to light, whereas others undergo only surface clouding reactions that are less dynamic. The solution and solid-state photoreaction mechanisms for these azido compounds were determined by carrying out product studies and obtaining laser flash photolysis of them in solution and solid nanocrystals. The mechanism was further supported by ESR spectroscopy and DFT calculations. To elucidate how the crystal lattice controls the photodynamic behavior, X-ray structures of the starting materials were obtained, and lattice energy calculations were carried out. The proposed reaction mechanism and the reasoning for how the nitrogen gas release controls the photodynamic behavior of the crystals will be discussed in detail.