Design of a LED Rapid Injection NMR System for Structure Elucidation and Kinetic Analyses

The design of an LED rapid-injection NMR (LED-RI-NMR) apparatus is described and showcased in kinetic studies for three photochemical reactions. The simple design of the LED- RI-NMR system allows for the introduction of both light and reagents into NMR samples for in situ reaction monitoring of reactive intermediates. The distinguishing features of the LED-RI- NMR system described herein includes (1) the ability to explore and intercept photogenerated intermediates via RI-NMR and (2) explore the photochemical properties of fleeting intermediates generated by RI-NMR. We have demonstrated the versatility of this new experimental tool for the kinetic study of organophotoredox cycloadditions, Wolff rearrangements, and azobenzene isomerization reactions.