Engineering Air-Stable Triarylmethyl Radicals with One Pyrrole Ring

Herein, seven air-stable triarylmethyl radicals (3b-3h), each featuring a pyrrole ring, were successfully synthesized. A comprehensive investigation into the linkages at the α-, β-, and N-positions of the pyrrole ring, along with various substituents, revealed that the p-π conjugation between the central radical carbon and the pyrrole ring plays a crucial role in the distribution of spin density and overall stability. Notably, radicals 3c to 3h displayed excellent electrochemical and photostability.