Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N₃ Charge-Transfer Complex

Advances in radical-based catalytic reactions have created a demand for understanding their mechanistic underpinnings. Here, we present the isolation, structural elucidation, and theoretical analysis of catalytically relevant charge-transfer species formed between azidyl radical (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). The unusual bond angles pancake bonding these two fragments highlight weak interactions this complex. This X-ray structure validates computational predictions as well proposals TEMPO-mediated azidation reactions.