Extremely Stable Perylene Bisimide‐Bridged Regioisomeric Diradicals and Their Redox Properties

Abstract

AbstractExcellent stability is an essential premise for organic diradicals to be used in organic electronic and spintronic devices. We have attached two tris(2,4,6‐trichlorophenyl)methyl (TTM) radical building blocks to the two sides of perylene bisimide (PBI) bridges and obtained two regioisomeric diradicals (1,6‐TTM‐PBI and 1,7‐TTM‐PBI). Both of the isomers show super stability rather than the monomeric TTM under ambient conditions, due to the increased conjugation and the electron‐withdrawing effects of the PBI bridges. The diradicals show distinct and reversible multistep redox processes, and a spectro‐electrochemistry investigation revealed the generation of organic mixed‐valence (MV) species during reduction processes. The two diradicals have singlet ground states, very small singlet–triplet energy gaps (ΔES‐T) and a pure open‐shell character (with diradical character y0=0.966 for 1,6‐TTM‐PBI and 0.967 for 1,7‐TTM‐PBI). This work opens a window to developing very stable diradicals and offers the opportunity of their further application in optical, electronic and magnetic devices.